Commit graph

289 commits

Author SHA1 Message Date
Arnd Bergmann
e7701557bf kasan: avoid -Wmaybe-uninitialized warning
gcc-7 produces this warning:

  mm/kasan/report.c: In function 'kasan_report':
  mm/kasan/report.c:351:3: error: 'info.first_bad_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     print_shadow_for_address(info->first_bad_addr);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  mm/kasan/report.c:360:27: note: 'info.first_bad_addr' was declared here

The code seems fine as we only print info.first_bad_addr when there is a
shadow, and we always initialize it in that case, but this is relatively
hard for gcc to figure out after the latest rework.

Adding an intialization to the most likely value together with the other
struct members shuts up that warning.

Fixes: b235b9808664 ("kasan: unify report headers")
Link: https://patchwork.kernel.org/patch/9641417/
Link: http://lkml.kernel.org/r/20170725152739.4176967-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Alexander Potapenko <glider@google.com>
Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-02 16:34:46 -07:00
Dmitry Vyukov
f06e8c584f kasan: Allow kasan_check_read/write() to accept pointers to volatiles
Currently kasan_check_read/write() accept 'const void*', make them
accept 'const volatile void*'. This is required for instrumentation
of atomic operations and there is just no reason to not allow that.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/33e5ec275c1ee89299245b2ebbccd63709c6021f.1498140838.git.dvyukov@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-26 13:08:54 +02:00
Colin Ian King
822d5ec258 kasan: make get_wild_bug_type() static
The helper function get_wild_bug_type() does not need to be in global
scope, so make it static.

Cleans up sparse warning:

  "symbol 'get_wild_bug_type' was not declared. Should it be static?"

Link: http://lkml.kernel.org/r/20170622090049.10658-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
Joonsoo Kim
f5bd62cd44 mm/kasan/kasan.c: rename XXX_is_zero to XXX_is_nonzero
They return positive value, that is, true, if non-zero value is found.
Rename them to reduce confusion.

Link: http://lkml.kernel.org/r/20170516012350.GA16015@js1304-desktop
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
Andrey Ryabinin
fa69b5989b mm/kasan: add support for memory hotplug
KASAN doesn't happen work with memory hotplug because hotplugged memory
doesn't have any shadow memory.  So any access to hotplugged memory
would cause a crash on shadow check.

Use memory hotplug notifier to allocate and map shadow memory when the
hotplugged memory is going online and free shadow after the memory
offlined.

Link: http://lkml.kernel.org/r/20170601162338.23540-4-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
Andrey Ryabinin
c634d807d9 mm/kasan: get rid of speculative shadow checks
For some unaligned memory accesses we have to check additional byte of
the shadow memory.  Currently we load that byte speculatively to have
only single load + branch on the optimistic fast path.

However, this approach has some downsides:

 - It's unaligned access, so this prevents porting KASAN on
   architectures which doesn't support unaligned accesses.

 - We have to map additional shadow page to prevent crash if speculative
   load happens near the end of the mapped memory. This would
   significantly complicate upcoming memory hotplug support.

I wasn't able to notice any performance degradation with this patch.  So
these speculative loads is just a pain with no gain, let's remove them.

Link: http://lkml.kernel.org/r/20170601162338.23540-1-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
Joonsoo Kim
458f7920f9 mm/kasan/kasan_init.c: use kasan_zero_pud for p4d table
There is missing optimization in zero_p4d_populate() that can save some
memory when mapping zero shadow.  Implement it like as others.

Link: http://lkml.kernel.org/r/1494829255-23946-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:33 -07:00
Linus Torvalds
de4d195308 Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
 "The main changes are:

   - Debloat RCU headers

   - Parallelize SRCU callback handling (plus overlapping patches)

   - Improve the performance of Tree SRCU on a CPU-hotplug stress test

   - Documentation updates

   - Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
  rcu: Open-code the rcu_cblist_n_lazy_cbs() function
  rcu: Open-code the rcu_cblist_n_cbs() function
  rcu: Open-code the rcu_cblist_empty() function
  rcu: Separately compile large rcu_segcblist functions
  srcu: Debloat the <linux/rcu_segcblist.h> header
  srcu: Adjust default auto-expediting holdoff
  srcu: Specify auto-expedite holdoff time
  srcu: Expedite first synchronize_srcu() when idle
  srcu: Expedited grace periods with reduced memory contention
  srcu: Make rcutorture writer stalls print SRCU GP state
  srcu: Exact tracking of srcu_data structures containing callbacks
  srcu: Make SRCU be built by default
  srcu: Fix Kconfig botch when SRCU not selected
  rcu: Make non-preemptive schedule be Tasks RCU quiescent state
  srcu: Expedite srcu_schedule_cbs_snp() callback invocation
  srcu: Parallelize callback handling
  kvm: Move srcu_struct fields to end of struct kvm
  rcu: Fix typo in PER_RCU_NODE_PERIOD header comment
  rcu: Use true/false in assignment to bool
  rcu: Use bool value directly
  ...
2017-05-10 10:30:46 -07:00
Michal Hocko
19809c2da2 mm, vmalloc: use __GFP_HIGHMEM implicitly
__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:13 -07:00
Andrey Konovalov
b193859936 kasan: separate report parts by empty lines
Makes the report easier to read.

Link: http://lkml.kernel.org/r/20170302134851.101218-10-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
5ab6d91ac9 kasan: improve double-free report format
Changes double-free report header from

  BUG: Double free or freeing an invalid pointer
  Unexpected shadow byte: 0xFB

to

  BUG: KASAN: double-free or invalid-free in kmalloc_oob_left+0xe5/0xef

This makes a bug uniquely identifiable by the first report line.  To
account for removing of the unexpected shadow value, print shadow bytes
at the end of the report as in reports for other kinds of bugs.

Link: http://lkml.kernel.org/r/20170302134851.101218-9-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
430a05f91d kasan: print page description after stacks
Moves page description after the stacks since it's less important.

Link: http://lkml.kernel.org/r/20170302134851.101218-8-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
0c06f1f86c kasan: improve slab object description
Changes slab object description from:

  Object at ffff880068388540, in cache kmalloc-128 size: 128

to:

  The buggy address belongs to the object at ffff880068388540
   which belongs to the cache kmalloc-128 of size 128
  The buggy address is located 123 bytes inside of
   128-byte region [ffff880068388540, ffff8800683885c0)

Makes it more explanatory and adds information about relative offset of
the accessed address to the start of the object.

Link: http://lkml.kernel.org/r/20170302134851.101218-7-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
7f0a84c23b kasan: change report header
Change report header format from:

  BUG: KASAN: use-after-free in unwind_get_return_address+0x28a/0x2c0 at addr ffff880069437950
  Read of size 8 by task insmod/3925

to:

  BUG: KASAN: use-after-free in unwind_get_return_address+0x28a/0x2c0
  Read of size 8 at addr ffff880069437950 by task insmod/3925

The exact access address is not usually important, so move it to the
second line.  This also makes the header look visually balanced.

Link: http://lkml.kernel.org/r/20170302134851.101218-6-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
db429f16e0 kasan: simplify address description logic
Simplify logic for describing a memory address.  Add addr_to_page()
helper function.

Makes the code easier to follow.

Link: http://lkml.kernel.org/r/20170302134851.101218-5-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
b6b72f4919 kasan: change allocation and freeing stack traces headers
Change stack traces headers from:

  Allocated:
  PID = 42

to:

  Allocated by task 42:

Makes the report one line shorter and look better.

Link: http://lkml.kernel.org/r/20170302134851.101218-4-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
7d418f7b0d kasan: unify report headers
Unify KASAN report header format for different kinds of bad memory
accesses.  Makes the code simpler.

Link: http://lkml.kernel.org/r/20170302134851.101218-3-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Andrey Konovalov
5e82cd1203 kasan: introduce helper functions for determining bug type
Patch series "kasan: improve error reports", v2.

This patchset improves KASAN reports by making them easier to read and a
little more detailed.  Also improves mm/kasan/report.c readability.

Effectively changes a use-after-free report to:

  ==================================================================
  BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan]
  Write of size 1 at addr ffff88006aa59da8 by task insmod/3951

  CPU: 1 PID: 3951 Comm: insmod Tainted: G    B           4.10.0+ #84
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
   dump_stack+0x292/0x398
   print_address_description+0x73/0x280
   kasan_report.part.2+0x207/0x2f0
   __asan_report_store1_noabort+0x2c/0x30
   kmalloc_uaf+0xaa/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc2
  RIP: 0033:0x7f22cfd0b9da
  RSP: 002b:00007ffe69118a78 EFLAGS: 00000206 ORIG_RAX: 00000000000000af
  RAX: ffffffffffffffda RBX: 0000555671242090 RCX: 00007f22cfd0b9da
  RDX: 00007f22cffcaf88 RSI: 000000000004df7e RDI: 00007f22d0399000
  RBP: 00007f22cffcaf88 R08: 0000000000000003 R09: 0000000000000000
  R10: 00007f22cfd07d0a R11: 0000000000000206 R12: 0000555671243190
  R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004

  Allocated by task 3951:
   save_stack_trace+0x16/0x20
   save_stack+0x43/0xd0
   kasan_kmalloc+0xad/0xe0
   kmem_cache_alloc_trace+0x82/0x270
   kmalloc_uaf+0x56/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc2

  Freed by task 3951:
   save_stack_trace+0x16/0x20
   save_stack+0x43/0xd0
   kasan_slab_free+0x72/0xc0
   kfree+0xe8/0x2b0
   kmalloc_uaf+0x85/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc

  The buggy address belongs to the object at ffff88006aa59da0
   which belongs to the cache kmalloc-16 of size 16
  The buggy address is located 8 bytes inside of
   16-byte region [ffff88006aa59da0, ffff88006aa59db0)
  The buggy address belongs to the page:
  page:ffffea0001aa9640 count:1 mapcount:0 mapping:          (null) index:0x0
  flags: 0x100000000000100(slab)
  raw: 0100000000000100 0000000000000000 0000000000000000 0000000180800080
  raw: ffffea0001abe380 0000000700000007 ffff88006c401b40 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff88006aa59c80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
   ffff88006aa59d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
  >ffff88006aa59d80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
                                    ^
   ffff88006aa59e00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
   ffff88006aa59e80: fb fb fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
  ==================================================================

from:

  ==================================================================
  BUG: KASAN: use-after-free in kmalloc_uaf+0xaa/0xb6 [test_kasan] at addr ffff88006c4dcb28
  Write of size 1 by task insmod/3984
  CPU: 1 PID: 3984 Comm: insmod Tainted: G    B           4.10.0+ #83
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
   dump_stack+0x292/0x398
   kasan_object_err+0x1c/0x70
   kasan_report.part.1+0x20e/0x4e0
   __asan_report_store1_noabort+0x2c/0x30
   kmalloc_uaf+0xaa/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc2
  RIP: 0033:0x7feca0f779da
  RSP: 002b:00007ffdfeae5218 EFLAGS: 00000206 ORIG_RAX: 00000000000000af
  RAX: ffffffffffffffda RBX: 000055a064c13090 RCX: 00007feca0f779da
  RDX: 00007feca1236f88 RSI: 000000000004df7e RDI: 00007feca1605000
  RBP: 00007feca1236f88 R08: 0000000000000003 R09: 0000000000000000
  R10: 00007feca0f73d0a R11: 0000000000000206 R12: 000055a064c14190
  R13: 000000000001fe81 R14: 0000000000000000 R15: 0000000000000004
  Object at ffff88006c4dcb20, in cache kmalloc-16 size: 16
  Allocated:
  PID = 3984
   save_stack_trace+0x16/0x20
   save_stack+0x43/0xd0
   kasan_kmalloc+0xad/0xe0
   kmem_cache_alloc_trace+0x82/0x270
   kmalloc_uaf+0x56/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc2
  Freed:
  PID = 3984
   save_stack_trace+0x16/0x20
   save_stack+0x43/0xd0
   kasan_slab_free+0x73/0xc0
   kfree+0xe8/0x2b0
   kmalloc_uaf+0x85/0xb6 [test_kasan]
   kmalloc_tests_init+0x4f/0xa48 [test_kasan]
   do_one_initcall+0xf3/0x390
   do_init_module+0x215/0x5d0
   load_module+0x54de/0x82b0
   SYSC_init_module+0x3be/0x430
   SyS_init_module+0x9/0x10
   entry_SYSCALL_64_fastpath+0x1f/0xc2
  Memory state around the buggy address:
   ffff88006c4dca00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
   ffff88006c4dca80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
  >ffff88006c4dcb00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
                                    ^
   ffff88006c4dcb80: fb fb fc fc 00 00 fc fc fb fb fc fc fb fb fc fc
   ffff88006c4dcc00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
  ==================================================================

This patch (of 9):

Introduce get_shadow_bug_type() function, which determines bug type
based on the shadow value for a particular kernel address.  Introduce
get_wild_bug_type() function, which determines bug type for addresses
which don't have a corresponding shadow value.

Link: http://lkml.kernel.org/r/20170302134851.101218-2-andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Ingo Molnar
58d30c36d4 Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:

 - Documentation updates.

 - Miscellaneous fixes.

 - Parallelize SRCU callback handling (plus overlapping patches).

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-23 11:12:44 +02:00
Paul E. McKenney
5f0d5a3ae7 mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
A group of Linux kernel hackers reported chasing a bug that resulted
from their assumption that SLAB_DESTROY_BY_RCU provided an existence
guarantee, that is, that no block from such a slab would be reallocated
during an RCU read-side critical section.  Of course, that is not the
case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
slab of blocks.

However, there is a phrase for this, namely "type safety".  This commit
therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
to avoid future instances of this sort of confusion.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
[ paulmck: Add comments mentioning the old name, as requested by Eric
  Dumazet, in order to help people familiar with the old name find
  the new one. ]
Acked-by: David Rientjes <rientjes@google.com>
2017-04-18 11:42:36 -07:00
Mark Rutland
b0845ce583 kasan: report only the first error by default
Disable kasan after the first report.  There are several reasons for
this:

 - Single bug quite often has multiple invalid memory accesses causing
   storm in the dmesg.

 - Write OOB access might corrupt metadata so the next report will print
   bogus alloc/free stacktraces.

 - Reports after the first easily could be not bugs by itself but just
   side effects of the first one.

Given that multiple reports usually only do harm, it makes sense to
disable kasan after the first one.  If user wants to see all the
reports, the boot-time parameter kasan_multi_shot must be used.

[aryabinin@virtuozzo.com: wrote changelog and doc, added missing include]
Link: http://lkml.kernel.org/r/20170323154416.30257-1-aryabinin@virtuozzo.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31 17:13:30 -07:00
Linus Torvalds
baeedc7158 Merge branch 'prep-for-5level'
Merge 5-level page table prep from Kirill Shutemov:
 "Here's relatively low-risk part of 5-level paging patchset. Merging it
  now will make x86 5-level paging enabling in v4.12 easier.

  The first patch is actually x86-specific: detect 5-level paging
  support. It boils down to single define.

  The rest of patchset converts Linux MMU abstraction from 4- to 5-level
  paging.

  Enabling of new abstraction in most cases requires adding single line
  of code in arch-specific code. The rest is taken care by asm-generic/.

  Changes to mm/ code are mostly mechanical: add support for new page
  table level -- p4d_t -- where we deal with pud_t now.

  v2:
   - fix build on microblaze (Michal);
   - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow();
   - acks from Michal"

* emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>:
  mm: introduce __p4d_alloc()
  mm: convert generic code to 5-level paging
  asm-generic: introduce <asm-generic/pgtable-nop4d.h>
  arch, mm: convert all architectures to use 5level-fixup.h
  asm-generic: introduce __ARCH_USE_5LEVEL_HACK
  asm-generic: introduce 5level-fixup.h
  x86/cpufeature: Add 5-level paging detection
2017-03-10 08:59:07 -08:00
Dmitry Vyukov
ce5bec54bb kasan: fix races in quarantine_remove_cache()
quarantine_remove_cache() frees all pending objects that belong to the
cache, before we destroy the cache itself.  However there are currently
two possibilities how it can fail to do so.

First, another thread can hold some of the objects from the cache in
temp list in quarantine_put().  quarantine_put() has a windows of
enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can
finish right in that window.  These objects will be later freed into the
destroyed cache.

Then, quarantine_reduce() has the same problem.  It grabs a batch of
objects from the global quarantine, then unlocks quarantine_lock and
then frees the batch.  quarantine_remove_cache() can finish while some
objects from the cache are still in the local to_free list in
quarantine_reduce().

Fix the race with quarantine_put() by disabling interrupts for the whole
duration of quarantine_put().  In combination with on_each_cpu() in
quarantine_remove_cache() it ensures that quarantine_remove_cache()
either sees the objects in the per-cpu list or in the global list.

Fix the race with quarantine_reduce() by protecting quarantine_reduce()
with srcu critical section and then doing synchronize_srcu() at the end
of quarantine_remove_cache().

I've done some assessment of how good synchronize_srcu() works in this
case.  And on a 4 CPU VM I see that it blocks waiting for pending read
critical sections in about 2-3% of cases.  Which looks good to me.

I suspect that these races are the root cause of some GPFs that I
episodically hit.  Previously I did not have any explanation for them.

  BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8
  IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
  PGD 6aeea067
  PUD 60ed7067
  PMD 0
  Oops: 0000 [#1] SMP KASAN
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  task: ffff88005f948040 task.stack: ffff880069818000
  RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
  RSP: 0018:ffff88006981f298 EFLAGS: 00010246
  RAX: ffffea0000ffff00 RBX: 0000000000000000 RCX: ffffea0000ffff1f
  RDX: 0000000000000000 RSI: ffff88003fffc3e0 RDI: 0000000000000000
  RBP: ffff88006981f2c0 R08: ffff88002fed7bd8 R09: 00000001001f000d
  R10: 00000000001f000d R11: ffff88006981f000 R12: ffff88003fffc3e0
  R13: ffff88006981f2d0 R14: ffffffff81877fae R15: 0000000080000000
  FS:  00007fb911a2d700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000000000c8 CR3: 0000000060ed6000 CR4: 00000000000006f0
  Call Trace:
   quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239
   kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590
   kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
   slab_post_alloc_hook mm/slab.h:456 [inline]
   slab_alloc_node mm/slub.c:2718 [inline]
   kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754
   __alloc_skb+0x10f/0x770 net/core/skbuff.c:219
   alloc_skb include/linux/skbuff.h:932 [inline]
   _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388
   sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline]
   sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746
   sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266
   sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962
   inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
   sock_sendmsg_nosec net/socket.c:633 [inline]
   sock_sendmsg+0xca/0x110 net/socket.c:643
   SYSC_sendto+0x660/0x810 net/socket.c:1685
   SyS_sendto+0x40/0x50 net/socket.c:1653

I am not sure about backporting.  The bug is quite hard to trigger, I've
seen it few times during our massive continuous testing (however, it
could be cause of some other episodic stray crashes as it leads to
memory corruption...).  If it is triggered, the consequences are very
bad -- almost definite bad memory corruption.  The fix is non trivial
and has chances of introducing new bugs.  I am also not sure how
actively people use KASAN on older releases.

[dvyukov@google.com: - sorted includes[
  Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com
Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Dmitry Vyukov
68fd814a33 kasan: resched in quarantine_remove_cache()
We see reported stalls/lockups in quarantine_remove_cache() on machines
with large amounts of RAM.  quarantine_remove_cache() needs to scan
whole quarantine in order to take out all objects belonging to the
cache.  Quarantine is currently 1/32-th of RAM, e.g.  on a machine with
256GB of memory that will be 8GB.  Moreover quarantine scanning is a
walk over uncached linked list, which is slow.

Add cond_resched() after scanning of each non-empty batch of objects.
Batches are specifically kept of reasonable size for quarantine_put().
On a machine with 256GB of RAM we should have ~512 non-empty batches,
each with 16MB of objects.

Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Kirill A. Shutemov
c2febafc67 mm: convert generic code to 5-level paging
Convert all non-architecture-specific code to 5-level paging.

It's mostly mechanical adding handling one more page table level in
places where we deal with pud_t.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 11:48:47 -08:00
Ingo Molnar
68db0cf106 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:36 +01:00
Ingo Molnar
af8601ad42 kasan, sched/headers: Uninline kasan_enable/disable_current()
<linux/kasan.h> is a low level header that is included early
in affected kernel headers. But it includes <linux/sched.h>
which complicates the cleanup of sched.h dependencies.

But kasan.h has almost no need for sched.h: its only use of
scheduler functionality is in two inline functions which are
not used very frequently - so uninline kasan_enable_current()
and kasan_disable_current().

Also add a <linux/sched.h> dependency to a .c file that depended
on kasan.h including it.

This paves the way to remove the <linux/sched.h> include from kasan.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:25 +01:00
Greg Thelen
f9fa1d919c kasan: drain quarantine of memcg slab objects
Per memcg slab accounting and kasan have a problem with kmem_cache
destruction.
 - kmem_cache_create() allocates a kmem_cache, which is used for
   allocations from processes running in root (top) memcg.
 - Processes running in non root memcg and allocating with either
   __GFP_ACCOUNT or from a SLAB_ACCOUNT cache use a per memcg
   kmem_cache.
 - Kasan catches use-after-free by having kfree() and kmem_cache_free()
   defer freeing of objects. Objects are placed in a quarantine.
 - kmem_cache_destroy() destroys root and non root kmem_caches. It takes
   care to drain the quarantine of objects from the root memcg's
   kmem_cache, but ignores objects associated with non root memcg. This
   causes leaks because quarantined per memcg objects refer to per memcg
   kmem cache being destroyed.

To see the problem:

 1) create a slab cache with kmem_cache_create(,,,SLAB_ACCOUNT,)
 2) from non root memcg, allocate and free a few objects from cache
 3) dispose of the cache with kmem_cache_destroy() kmem_cache_destroy()
    will trigger a "Slab cache still has objects" warning indicating
    that the per memcg kmem_cache structure was leaked.

Fix the leak by draining kasan quarantined objects allocated from non
root memcg.

Racing memcg deletion is tricky, but handled.  kmem_cache_destroy() =>
shutdown_memcg_caches() => __shutdown_memcg_cache() => shutdown_cache()
flushes per memcg quarantined objects, even if that memcg has been
rmdir'd and gone through memcg_deactivate_kmem_caches().

This leak only affects destroyed SLAB_ACCOUNT kmem caches when kasan is
enabled.  So I don't think it's worth patching stable kernels.

Link: http://lkml.kernel.org/r/1482257462-36948-1-git-send-email-gthelen@google.com
Signed-off-by: Greg Thelen <gthelen@google.com>
Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Linus Torvalds
ca78d3173c arm64 updates for 4.11:
- Errata workarounds for Qualcomm's Falkor CPU
 - Qualcomm L2 Cache PMU driver
 - Qualcomm SMCCC firmware quirk
 - Support for DEBUG_VIRTUAL
 - CPU feature detection for userspace via MRS emulation
 - Preliminary work for the Statistical Profiling Extension
 - Misc cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 - Errata workarounds for Qualcomm's Falkor CPU
 - Qualcomm L2 Cache PMU driver
 - Qualcomm SMCCC firmware quirk
 - Support for DEBUG_VIRTUAL
 - CPU feature detection for userspace via MRS emulation
 - Preliminary work for the Statistical Profiling Extension
 - Misc cleanups and non-critical fixes

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (74 commits)
  arm64/kprobes: consistently handle MRS/MSR with XZR
  arm64: cpufeature: correctly handle MRS to XZR
  arm64: traps: correctly handle MRS/MSR with XZR
  arm64: ptrace: add XZR-safe regs accessors
  arm64: include asm/assembler.h in entry-ftrace.S
  arm64: fix warning about swapper_pg_dir overflow
  arm64: Work around Falkor erratum 1003
  arm64: head.S: Enable EL1 (host) access to SPE when entered at EL2
  arm64: arch_timer: document Hisilicon erratum 161010101
  arm64: use is_vmalloc_addr
  arm64: use linux/sizes.h for constants
  arm64: uaccess: consistently check object sizes
  perf: add qcom l2 cache perf events driver
  arm64: remove wrong CONFIG_PROC_SYSCTL ifdef
  ARM: smccc: Update HVC comment to describe new quirk parameter
  arm64: do not trace atomic operations
  ACPI/IORT: Fix the error return code in iort_add_smmu_platform_device()
  ACPI/IORT: Fix iort_node_get_id() mapping entries indexing
  arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA
  perf: xgene: Include module.h
  ...
2017-02-22 10:46:44 -08:00
Peter Zijlstra
4f40c6e562 kasan: respect /proc/sys/kernel/traceoff_on_warning
After much waiting I finally reproduced a KASAN issue, only to find my
trace-buffer empty of useful information because it got spooled out :/

Make kasan_report honour the /proc/sys/kernel/traceoff_on_warning
interface.

Link: http://lkml.kernel.org/r/20170125164106.3514-1-aryabinin@virtuozzo.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 14:13:19 -08:00
Laura Abbott
5c6a84a3f4 mm/kasan: Switch to using __pa_symbol and lm_alias
__pa_symbol is the correct API to find the physical address of symbols.
Switch to it to allow for debugging APIs to work correctly. Other
functions such as p*d_populate may call __pa internally. Ensure that the
address passed is in the linear region by calling lm_alias.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-01-11 13:56:50 +00:00
Linus Torvalds
7b9dc3f75f Power management material for v4.10-rc1
- New cpufreq driver for Broadcom STB SoCs and a Device Tree binding
    for it (Markus Mayer).
 
  - Support for ARM Integrator/AP and Integrator/CP in the generic
    DT cpufreq driver and elimination of the old Integrator cpufreq
    driver (Linus Walleij).
 
  - Support for the zx296718, r8a7743 and r8a7745, Socionext UniPhier,
    and PXA SoCs in the the generic DT cpufreq driver (Baoyou Xie,
    Geert Uytterhoeven, Masahiro Yamada, Robert Jarzmik).
 
  - cpufreq core fix to eliminate races that may lead to using
    inactive policy objects and related cleanups (Rafael Wysocki).
 
  - cpufreq schedutil governor update to make it use SCHED_FIFO
    kernel threads (instead of regular workqueues) for doing delayed
    work (to reduce the response latency in some cases) and related
    cleanups (Viresh Kumar).
 
  - New cpufreq sysfs attribute for resetting statistics (Markus
    Mayer).
 
  - cpufreq governors fixes and cleanups (Chen Yu, Stratos Karafotis,
    Viresh Kumar).
 
  - Support for using generic cpufreq governors in the intel_pstate
    driver (Rafael Wysocki).
 
  - Support for per-logical-CPU P-state limits and the EPP/EPB
    (Energy Performance Preference/Energy Performance Bias) knobs
    in the intel_pstate driver (Srinivas Pandruvada).
 
  - New CPU ID for Knights Mill in intel_pstate (Piotr Luc).
 
  - intel_pstate driver modification to use the P-state selection
    algorithm based on CPU load on platforms with the system profile
    in the ACPI tables set to "mobile" (Srinivas Pandruvada).
 
  - intel_pstate driver cleanups (Arnd Bergmann, Rafael Wysocki,
    Srinivas Pandruvada).
 
  - cpufreq powernv driver updates including fast switching support
    (for the schedutil governor), fixes and cleanus (Akshay Adiga,
    Andrew Donnellan, Denis Kirjanov).
 
  - acpi-cpufreq driver rework to switch it over to the new CPU
    offline/online state machine (Sebastian Andrzej Siewior).
 
  - Assorted cleanups in cpufreq drivers (Wei Yongjun, Prashanth
    Prakash).
 
  - Idle injection rework (to make it use the regular idle path
    instead of a home-grown custom one) and related powerclamp
    thermal driver updates (Peter Zijlstra, Jacob Pan, Petr Mladek,
    Sebastian Andrzej Siewior).
 
  - New CPU IDs for Atom Z34xx and Knights Mill in intel_idle (Andy
    Shevchenko, Piotr Luc).
 
  - intel_idle driver cleanups and switch over to using the new CPU
    offline/online state machine (Anna-Maria Gleixner, Sebastian
    Andrzej Siewior).
 
  - cpuidle DT driver update to support suspend-to-idle properly
    (Sudeep Holla).
 
  - cpuidle core cleanups and misc updates (Daniel Lezcano, Pan Bian,
    Rafael Wysocki).
 
  - Preliminary support for power domains including CPUs in the
    generic power domains (genpd) framework and related DT bindings
    (Lina Iyer).
 
  - Assorted fixes and cleanups in the generic power domains (genpd)
    framework (Colin Ian King, Dan Carpenter, Geert Uytterhoeven).
 
  - Preliminary support for devices with multiple voltage regulators
    and related fixes and cleanups in the Operating Performance Points
    (OPP) library (Viresh Kumar, Masahiro Yamada, Stephen Boyd).
 
  - System sleep state selection interface rework to make it easier
    to support suspend-to-idle as the default system suspend method
    (Rafael Wysocki).
 
  - PM core fixes and cleanups, mostly related to the interactions
    between the system suspend and runtime PM frameworks (Ulf Hansson,
    Sahitya Tummala, Tony Lindgren).
 
  - Latency tolerance PM QoS framework imorovements (Andrew
    Lutomirski).
 
  - New Knights Mill CPU ID for the Intel RAPL power capping driver
    (Piotr Luc).
 
  - Intel RAPL power capping driver fixes, cleanups and switch over
    to using the new CPU offline/online state machine (Jacob Pan,
    Thomas Gleixner, Sebastian Andrzej Siewior).
 
  - Fixes and cleanups in the exynos-ppmu, exynos-nocp, rk3399_dmc,
    rockchip-dfi devfreq drivers and the devfreq core (Axel Lin,
    Chanwoo Choi, Javier Martinez Canillas, MyungJoo Ham, Viresh
    Kumar).
 
  - Fix for false-positive KASAN warnings during resume from ACPI S3
    (suspend-to-RAM) on x86 (Josh Poimboeuf).
 
  - Memory map verification during resume from hibernation on x86 to
    ensure a consistent address space layout (Chen Yu).
 
  - Wakeup sources debugging enhancement (Xing Wei).
 
  - rockchip-io AVS driver cleanup (Shawn Lin).
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Merge tag 'pm-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "Again, cpufreq gets more changes than the other parts this time (one
  new driver, one old driver less, a bunch of enhancements of the
  existing code, new CPU IDs, fixes, cleanups)

  There also are some changes in cpuidle (idle injection rework, a
  couple of new CPU IDs, online/offline rework in intel_idle, fixes and
  cleanups), in the generic power domains framework (mostly related to
  supporting power domains containing CPUs), and in the Operating
  Performance Points (OPP) library (mostly related to supporting devices
  with multiple voltage regulators)

  In addition to that, the system sleep state selection interface is
  modified to make it easier for distributions with unchanged user space
  to support suspend-to-idle as the default system suspend method, some
  issues are fixed in the PM core, the latency tolerance PM QoS
  framework is improved a bit, the Intel RAPL power capping driver is
  cleaned up and there are some fixes and cleanups in the devfreq
  subsystem

  Specifics:

   - New cpufreq driver for Broadcom STB SoCs and a Device Tree binding
     for it (Markus Mayer)

   - Support for ARM Integrator/AP and Integrator/CP in the generic DT
     cpufreq driver and elimination of the old Integrator cpufreq driver
     (Linus Walleij)

   - Support for the zx296718, r8a7743 and r8a7745, Socionext UniPhier,
     and PXA SoCs in the the generic DT cpufreq driver (Baoyou Xie,
     Geert Uytterhoeven, Masahiro Yamada, Robert Jarzmik)

   - cpufreq core fix to eliminate races that may lead to using inactive
     policy objects and related cleanups (Rafael Wysocki)

   - cpufreq schedutil governor update to make it use SCHED_FIFO kernel
     threads (instead of regular workqueues) for doing delayed work (to
     reduce the response latency in some cases) and related cleanups
     (Viresh Kumar)

   - New cpufreq sysfs attribute for resetting statistics (Markus Mayer)

   - cpufreq governors fixes and cleanups (Chen Yu, Stratos Karafotis,
     Viresh Kumar)

   - Support for using generic cpufreq governors in the intel_pstate
     driver (Rafael Wysocki)

   - Support for per-logical-CPU P-state limits and the EPP/EPB (Energy
     Performance Preference/Energy Performance Bias) knobs in the
     intel_pstate driver (Srinivas Pandruvada)

   - New CPU ID for Knights Mill in intel_pstate (Piotr Luc)

   - intel_pstate driver modification to use the P-state selection
     algorithm based on CPU load on platforms with the system profile in
     the ACPI tables set to "mobile" (Srinivas Pandruvada)

   - intel_pstate driver cleanups (Arnd Bergmann, Rafael Wysocki,
     Srinivas Pandruvada)

   - cpufreq powernv driver updates including fast switching support
     (for the schedutil governor), fixes and cleanus (Akshay Adiga,
     Andrew Donnellan, Denis Kirjanov)

   - acpi-cpufreq driver rework to switch it over to the new CPU
     offline/online state machine (Sebastian Andrzej Siewior)

   - Assorted cleanups in cpufreq drivers (Wei Yongjun, Prashanth
     Prakash)

   - Idle injection rework (to make it use the regular idle path instead
     of a home-grown custom one) and related powerclamp thermal driver
     updates (Peter Zijlstra, Jacob Pan, Petr Mladek, Sebastian Andrzej
     Siewior)

   - New CPU IDs for Atom Z34xx and Knights Mill in intel_idle (Andy
     Shevchenko, Piotr Luc)

   - intel_idle driver cleanups and switch over to using the new CPU
     offline/online state machine (Anna-Maria Gleixner, Sebastian
     Andrzej Siewior)

   - cpuidle DT driver update to support suspend-to-idle properly
     (Sudeep Holla)

   - cpuidle core cleanups and misc updates (Daniel Lezcano, Pan Bian,
     Rafael Wysocki)

   - Preliminary support for power domains including CPUs in the generic
     power domains (genpd) framework and related DT bindings (Lina Iyer)

   - Assorted fixes and cleanups in the generic power domains (genpd)
     framework (Colin Ian King, Dan Carpenter, Geert Uytterhoeven)

   - Preliminary support for devices with multiple voltage regulators
     and related fixes and cleanups in the Operating Performance Points
     (OPP) library (Viresh Kumar, Masahiro Yamada, Stephen Boyd)

   - System sleep state selection interface rework to make it easier to
     support suspend-to-idle as the default system suspend method
     (Rafael Wysocki)

   - PM core fixes and cleanups, mostly related to the interactions
     between the system suspend and runtime PM frameworks (Ulf Hansson,
     Sahitya Tummala, Tony Lindgren)

   - Latency tolerance PM QoS framework imorovements (Andrew Lutomirski)

   - New Knights Mill CPU ID for the Intel RAPL power capping driver
     (Piotr Luc)

   - Intel RAPL power capping driver fixes, cleanups and switch over to
     using the new CPU offline/online state machine (Jacob Pan, Thomas
     Gleixner, Sebastian Andrzej Siewior)

   - Fixes and cleanups in the exynos-ppmu, exynos-nocp, rk3399_dmc,
     rockchip-dfi devfreq drivers and the devfreq core (Axel Lin,
     Chanwoo Choi, Javier Martinez Canillas, MyungJoo Ham, Viresh Kumar)

   - Fix for false-positive KASAN warnings during resume from ACPI S3
     (suspend-to-RAM) on x86 (Josh Poimboeuf)

   - Memory map verification during resume from hibernation on x86 to
     ensure a consistent address space layout (Chen Yu)

   - Wakeup sources debugging enhancement (Xing Wei)

   - rockchip-io AVS driver cleanup (Shawn Lin)"

* tag 'pm-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (127 commits)
  devfreq: rk3399_dmc: Don't use OPP structures outside of RCU locks
  devfreq: rk3399_dmc: Remove dangling rcu_read_unlock()
  devfreq: exynos: Don't use OPP structures outside of RCU locks
  Documentation: intel_pstate: Document HWP energy/performance hints
  cpufreq: intel_pstate: Support for energy performance hints with HWP
  cpufreq: intel_pstate: Add locking around HWP requests
  PM / sleep: Print active wakeup sources when blocking on wakeup_count reads
  PM / core: Fix bug in the error handling of async suspend
  PM / wakeirq: Fix dedicated wakeirq for drivers not using autosuspend
  PM / Domains: Fix compatible for domain idle state
  PM / OPP: Don't WARN on multiple calls to dev_pm_opp_set_regulators()
  PM / OPP: Allow platform specific custom set_opp() callbacks
  PM / OPP: Separate out _generic_set_opp()
  PM / OPP: Add infrastructure to manage multiple regulators
  PM / OPP: Pass struct dev_pm_opp_supply to _set_opp_voltage()
  PM / OPP: Manage supply's voltage/current in a separate structure
  PM / OPP: Don't use OPP structure outside of rcu protected section
  PM / OPP: Reword binding supporting multiple regulators per device
  PM / OPP: Fix incorrect cpu-supply property in binding
  cpuidle: Add a kerneldoc comment to cpuidle_use_deepest_state()
  ..
2016-12-13 10:41:53 -08:00
Dmitry Vyukov
64abdcb243 kasan: eliminate long stalls during quarantine reduction
Currently we dedicate 1/32 of RAM for quarantine and then reduce it by
1/4 of total quarantine size.  This can be a significant amount of
memory.  For example, with 4GB of RAM total quarantine size is 128MB and
it is reduced by 32MB at a time.  With 128GB of RAM total quarantine
size is 4GB and it is reduced by 1GB.  This leads to several problems:

 - freeing 1GB can take tens of seconds, causes rcu stall warnings and
   just introduces unexpected long delays at random places
 - if kmalloc() is called under a mutex, other threads stall on that
   mutex while a thread reduces quarantine
 - threads wait on quarantine_lock while one thread grabs a large batch
   of objects to evict
 - we walk the uncached list of object to free twice which makes all of
   the above worse
 - when a thread frees objects, they are already not accounted against
   global_quarantine.bytes; as the result we can have quarantine_size
   bytes in quarantine + unbounded amount of memory in large batches in
   threads that are in process of freeing

Reduce size of quarantine in smaller batches to reduce the delays.  The
only reason to reduce it in batches is amortization of overheads, the
new batch size of 1MB should be well enough to amortize spinlock
lock/unlock and few function calls.

Plus organize quarantine as a FIFO array of batches.  This allows to not
walk the list in quarantine_reduce() under quarantine_lock, which in
turn reduces contention and is just faster.

This improves performance of heavy load (syzkaller fuzzing) by ~20% with
4 CPUs and 32GB of RAM.  Also this eliminates frequent (every 5 sec)
drops of CPU consumption from ~400% to ~100% (one thread reduces
quarantine while others are waiting on a mutex).

Some reference numbers:
1. Machine with 4 CPUs and 4GB of memory. Quarantine size 128MB.
   Currently we free 32MB at at time.
   With new code we free 1MB at a time (1024 batches, ~128 are used).
2. Machine with 32 CPUs and 128GB of memory. Quarantine size 4GB.
   Currently we free 1GB at at time.
   With new code we free 8MB at a time (1024 batches, ~512 are used).
3. Machine with 4096 CPUs and 1TB of memory. Quarantine size 32GB.
   Currently we free 8GB at at time.
   With new code we free 4MB at a time (16K batches, ~8K are used).

Link: http://lkml.kernel.org/r/1478756952-18695-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Dmitry Vyukov
5c5c1f36ce kasan: support panic_on_warn
If user sets panic_on_warn, he wants kernel to panic if there is
anything barely wrong with the kernel.  KASAN-detected errors are
definitely not less benign than an arbitrary kernel WARNING.

Panic after KASAN errors if panic_on_warn is set.

We use this for continuous fuzzing where we want kernel to stop and
reboot on any error.

Link: http://lkml.kernel.org/r/1476694764-31986-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Rafael J. Wysocki
631ddaba59 Merge branches 'pm-sleep' and 'powercap'
* pm-sleep:
  PM / sleep: Print active wakeup sources when blocking on wakeup_count reads
  x86/suspend: fix false positive KASAN warning on suspend/resume
  PM / sleep / ACPI: Use the ACPI_FADT_LOW_POWER_S0 flag
  PM / sleep: System sleep state selection interface rework
  PM / hibernate: Verify the consistent of e820 memory map by md5 digest

* powercap:
  powercap / RAPL: Add Knights Mill CPUID
  powercap/intel_rapl: fix and tidy up error handling
  powercap/intel_rapl: Track active CPUs internally
  powercap/intel_rapl: Cleanup duplicated init code
  powercap/intel rapl: Convert to hotplug state machine
  powercap/intel_rapl: Propagate error code when registration fails
  powercap/intel_rapl: Add missing domain data update on hotplug
2016-12-12 20:46:35 +01:00
Josh Poimboeuf
b53f40db59 x86/suspend: fix false positive KASAN warning on suspend/resume
Resuming from a suspend operation is showing a KASAN false positive
warning:

  BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x11d/0x130 at addr ffff8803867d7878
  Read of size 8 by task pm-suspend/7774
  page:ffffea000e19f5c0 count:0 mapcount:0 mapping:          (null) index:0x0
  flags: 0x2ffff0000000000()
  page dumped because: kasan: bad access detected
  CPU: 0 PID: 7774 Comm: pm-suspend Tainted: G    B           4.9.0-rc7+ #8
  Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
  Call Trace:
    dump_stack+0x63/0x82
    kasan_report_error+0x4b4/0x4e0
    ? acpi_hw_read_port+0xd0/0x1ea
    ? kfree_const+0x22/0x30
    ? acpi_hw_validate_io_request+0x1a6/0x1a6
    __asan_report_load8_noabort+0x61/0x70
    ? unwind_get_return_address+0x11d/0x130
    unwind_get_return_address+0x11d/0x130
    ? unwind_next_frame+0x97/0xf0
    __save_stack_trace+0x92/0x100
    save_stack_trace+0x1b/0x20
    save_stack+0x46/0xd0
    ? save_stack_trace+0x1b/0x20
    ? save_stack+0x46/0xd0
    ? kasan_kmalloc+0xad/0xe0
    ? kasan_slab_alloc+0x12/0x20
    ? acpi_hw_read+0x2b6/0x3aa
    ? acpi_hw_validate_register+0x20b/0x20b
    ? acpi_hw_write_port+0x72/0xc7
    ? acpi_hw_write+0x11f/0x15f
    ? acpi_hw_read_multiple+0x19f/0x19f
    ? memcpy+0x45/0x50
    ? acpi_hw_write_port+0x72/0xc7
    ? acpi_hw_write+0x11f/0x15f
    ? acpi_hw_read_multiple+0x19f/0x19f
    ? kasan_unpoison_shadow+0x36/0x50
    kasan_kmalloc+0xad/0xe0
    kasan_slab_alloc+0x12/0x20
    kmem_cache_alloc_trace+0xbc/0x1e0
    ? acpi_get_sleep_type_data+0x9a/0x578
    acpi_get_sleep_type_data+0x9a/0x578
    acpi_hw_legacy_wake_prep+0x88/0x22c
    ? acpi_hw_legacy_sleep+0x3c7/0x3c7
    ? acpi_write_bit_register+0x28d/0x2d3
    ? acpi_read_bit_register+0x19b/0x19b
    acpi_hw_sleep_dispatch+0xb5/0xba
    acpi_leave_sleep_state_prep+0x17/0x19
    acpi_suspend_enter+0x154/0x1e0
    ? trace_suspend_resume+0xe8/0xe8
    suspend_devices_and_enter+0xb09/0xdb0
    ? printk+0xa8/0xd8
    ? arch_suspend_enable_irqs+0x20/0x20
    ? try_to_freeze_tasks+0x295/0x600
    pm_suspend+0x6c9/0x780
    ? finish_wait+0x1f0/0x1f0
    ? suspend_devices_and_enter+0xdb0/0xdb0
    state_store+0xa2/0x120
    ? kobj_attr_show+0x60/0x60
    kobj_attr_store+0x36/0x70
    sysfs_kf_write+0x131/0x200
    kernfs_fop_write+0x295/0x3f0
    __vfs_write+0xef/0x760
    ? handle_mm_fault+0x1346/0x35e0
    ? do_iter_readv_writev+0x660/0x660
    ? __pmd_alloc+0x310/0x310
    ? do_lock_file_wait+0x1e0/0x1e0
    ? apparmor_file_permission+0x18/0x20
    ? security_file_permission+0x73/0x1c0
    ? rw_verify_area+0xbd/0x2b0
    vfs_write+0x149/0x4a0
    SyS_write+0xd9/0x1c0
    ? SyS_read+0x1c0/0x1c0
    entry_SYSCALL_64_fastpath+0x1e/0xad
  Memory state around the buggy address:
   ffff8803867d7700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   ffff8803867d7780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >ffff8803867d7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f4
                                                                  ^
   ffff8803867d7880: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
   ffff8803867d7900: 00 00 00 f1 f1 f1 f1 04 f4 f4 f4 f3 f3 f3 f3 00

KASAN instrumentation poisons the stack when entering a function and
unpoisons it when exiting the function.  However, in the suspend path,
some functions never return, so their stack never gets unpoisoned,
resulting in stale KASAN shadow data which can cause later false
positive warnings like the one above.

Reported-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-12-06 02:22:44 +01:00
Dmitry Vyukov
828347f8f9 kasan: support use-after-scope detection
Gcc revision 241896 implements use-after-scope detection.  Will be
available in gcc 7.  Support it in KASAN.

Gcc emits 2 new callbacks to poison/unpoison large stack objects when
they go in/out of scope.  Implement the callbacks and add a test.

[dvyukov@google.com: v3]
  Link: http://lkml.kernel.org/r/1479998292-144502-1-git-send-email-dvyukov@google.com
Link: http://lkml.kernel.org/r/1479226045-145148-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-30 16:32:52 -08:00
Dmitry Vyukov
045d599a28 kasan: update kasan_global for gcc 7
kasan_global struct is part of compiler/runtime ABI.  gcc revision
241983 has added a new field to kasan_global struct.  Update kernel
definition of kasan_global struct to include the new field.

Without this patch KASAN is broken with gcc 7.

Link: http://lkml.kernel.org/r/1479219743-28682-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-30 16:32:52 -08:00
Dmitry Vyukov
9f7d416c36 kprobes: Unpoison stack in jprobe_return() for KASAN
I observed false KSAN positives in the sctp code, when
sctp uses jprobe_return() in jsctp_sf_eat_sack().

The stray 0xf4 in shadow memory are stack redzones:

[     ] ==================================================================
[     ] BUG: KASAN: stack-out-of-bounds in memcmp+0xe9/0x150 at addr ffff88005e48f480
[     ] Read of size 1 by task syz-executor/18535
[     ] page:ffffea00017923c0 count:0 mapcount:0 mapping:          (null) index:0x0
[     ] flags: 0x1fffc0000000000()
[     ] page dumped because: kasan: bad access detected
[     ] CPU: 1 PID: 18535 Comm: syz-executor Not tainted 4.8.0+ #28
[     ] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[     ]  ffff88005e48f2d0 ffffffff82d2b849 ffffffff0bc91e90 fffffbfff10971e8
[     ]  ffffed000bc91e90 ffffed000bc91e90 0000000000000001 0000000000000000
[     ]  ffff88005e48f480 ffff88005e48f350 ffffffff817d3169 ffff88005e48f370
[     ] Call Trace:
[     ]  [<ffffffff82d2b849>] dump_stack+0x12e/0x185
[     ]  [<ffffffff817d3169>] kasan_report+0x489/0x4b0
[     ]  [<ffffffff817d31a9>] __asan_report_load1_noabort+0x19/0x20
[     ]  [<ffffffff82d49529>] memcmp+0xe9/0x150
[     ]  [<ffffffff82df7486>] depot_save_stack+0x176/0x5c0
[     ]  [<ffffffff817d2031>] save_stack+0xb1/0xd0
[     ]  [<ffffffff817d27f2>] kasan_slab_free+0x72/0xc0
[     ]  [<ffffffff817d05b8>] kfree+0xc8/0x2a0
[     ]  [<ffffffff85b03f19>] skb_free_head+0x79/0xb0
[     ]  [<ffffffff85b0900a>] skb_release_data+0x37a/0x420
[     ]  [<ffffffff85b090ff>] skb_release_all+0x4f/0x60
[     ]  [<ffffffff85b11348>] consume_skb+0x138/0x370
[     ]  [<ffffffff8676ad7b>] sctp_chunk_put+0xcb/0x180
[     ]  [<ffffffff8676ae88>] sctp_chunk_free+0x58/0x70
[     ]  [<ffffffff8677fa5f>] sctp_inq_pop+0x68f/0xef0
[     ]  [<ffffffff8675ee36>] sctp_assoc_bh_rcv+0xd6/0x4b0
[     ]  [<ffffffff8677f2c1>] sctp_inq_push+0x131/0x190
[     ]  [<ffffffff867bad69>] sctp_backlog_rcv+0xe9/0xa20
[ ... ]
[     ] Memory state around the buggy address:
[     ]  ffff88005e48f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]  ffff88005e48f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ] >ffff88005e48f480: f4 f4 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]                    ^
[     ]  ffff88005e48f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ]  ffff88005e48f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[     ] ==================================================================

KASAN stack instrumentation poisons stack redzones on function entry
and unpoisons them on function exit. If a function exits abnormally
(e.g. with a longjmp like jprobe_return()), stack redzones are left
poisoned. Later this leads to random KASAN false reports.

Unpoison stack redzones in the frames we are going to jump over
before doing actual longjmp in jprobe_return().

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: kasan-dev@googlegroups.com
Cc: surovegin@google.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/1476454043-101898-1-git-send-email-dvyukov@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-16 11:02:31 +02:00
Alexander Potapenko
bcbf0d566b kasan: remove the unnecessary WARN_ONCE from quarantine.c
It's quite unlikely that the user will so little memory that the per-CPU
quarantines won't fit into the given fraction of the available memory.
Even in that case he won't be able to do anything with the information
given in the warning.

Link: http://lkml.kernel.org/r/1470929182-101413-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-11 16:58:14 -07:00
Alexander Potapenko
c3cee37228 kasan: avoid overflowing quarantine size on low memory systems
If the total amount of memory assigned to quarantine is less than the
amount of memory assigned to per-cpu quarantines, |new_quarantine_size|
may overflow.  Instead, set it to zero.

[akpm@linux-foundation.org: cleanup: use WARN_ONCE return value]
Link: http://lkml.kernel.org/r/1470063563-96266-1-git-send-email-glider@google.com
Fixes: 55834c5909 ("mm: kasan: initial memory quarantine implementation")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
7e08897893 kasan: improve double-free reports
Currently we just dump stack in case of double free bug.
Let's dump all info about the object that we have.

[aryabinin@virtuozzo.com: change double free message per Alexander]
  Link: http://lkml.kernel.org/r/1470153654-30160-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1470062715-14077-6-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
b3cbd9bf77 mm/kasan: get rid of ->state in struct kasan_alloc_meta
The state of object currently tracked in two places - shadow memory, and
the ->state field in struct kasan_alloc_meta.  We can get rid of the
latter.  The will save us a little bit of memory.  Also, this allow us
to move free stack into struct kasan_alloc_meta, without increasing
memory consumption.  So now we should always know when the last time the
object was freed.  This may be useful for long delayed use-after-free
bugs.

As a side effect this fixes following UBSAN warning:
	UBSAN: Undefined behaviour in mm/kasan/quarantine.c:102:13
	member access within misaligned address ffff88000d1efebc for type 'struct qlist_node'
	which requires 8 byte alignment

Link: http://lkml.kernel.org/r/1470062715-14077-5-git-send-email-aryabinin@virtuozzo.com
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
47b5c2a0f0 mm/kasan: get rid of ->alloc_size in struct kasan_alloc_meta
Size of slab object already stored in cache->object_size.

Note, that kmalloc() internally rounds up size of allocation, so
object_size may be not equal to alloc_size, but, usually we don't need
to know the exact size of allocated object.  In case if we need that
information, we still can figure it out from the report.  The dump of
shadow memory allows to identify the end of allocated memory, and
thereby the exact allocation size.

Link: http://lkml.kernel.org/r/1470062715-14077-4-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
f7376aed6c mm/kasan, slub: don't disable interrupts when object leaves quarantine
SLUB doesn't require disabled interrupts to call ___cache_free().

Link: http://lkml.kernel.org/r/1470062715-14077-3-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
4b3ec5a3f4 mm/kasan: don't reduce quarantine in atomic contexts
Currently we call quarantine_reduce() for ___GFP_KSWAPD_RECLAIM (implied
by __GFP_RECLAIM) allocation.  So, basically we call it on almost every
allocation.  quarantine_reduce() sometimes is heavy operation, and
calling it with disabled interrupts may trigger hard LOCKUP:

 NMI watchdog: Watchdog detected hard LOCKUP on cpu 2irq event stamp: 1411258
 Call Trace:
  <NMI>   dump_stack+0x68/0x96
   watchdog_overflow_callback+0x15b/0x190
   __perf_event_overflow+0x1b1/0x540
   perf_event_overflow+0x14/0x20
   intel_pmu_handle_irq+0x36a/0xad0
   perf_event_nmi_handler+0x2c/0x50
   nmi_handle+0x128/0x480
   default_do_nmi+0xb2/0x210
   do_nmi+0x1aa/0x220
   end_repeat_nmi+0x1a/0x1e
  <<EOE>>   __kernel_text_address+0x86/0xb0
   print_context_stack+0x7b/0x100
   dump_trace+0x12b/0x350
   save_stack_trace+0x2b/0x50
   set_track+0x83/0x140
   free_debug_processing+0x1aa/0x420
   __slab_free+0x1d6/0x2e0
   ___cache_free+0xb6/0xd0
   qlist_free_all+0x83/0x100
   quarantine_reduce+0x177/0x1b0
   kasan_kmalloc+0xf3/0x100

Reduce the quarantine_reduce iff direct reclaim is allowed.

Fixes: 55834c59098d("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/1470062715-14077-2-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Andrey Ryabinin
4a3d308d66 mm/kasan: fix corruptions and false positive reports
Once an object is put into quarantine, we no longer own it, i.e.  object
could leave the quarantine and be reallocated.  So having set_track()
call after the quarantine_put() may corrupt slab objects.

 BUG kmalloc-4096 (Not tainted): Poison overwritten
 -----------------------------------------------------------------------------
 Disabling lock debugging due to kernel taint
 INFO: 0xffff8804540de850-0xffff8804540de857. First byte 0xb5 instead of 0x6b
...
 INFO: Freed in qlist_free_all+0x42/0x100 age=75 cpu=3 pid=24492
  __slab_free+0x1d6/0x2e0
  ___cache_free+0xb6/0xd0
  qlist_free_all+0x83/0x100
  quarantine_reduce+0x177/0x1b0
  kasan_kmalloc+0xf3/0x100
  kasan_slab_alloc+0x12/0x20
  kmem_cache_alloc+0x109/0x3e0
  mmap_region+0x53e/0xe40
  do_mmap+0x70f/0xa50
  vm_mmap_pgoff+0x147/0x1b0
  SyS_mmap_pgoff+0x2c7/0x5b0
  SyS_mmap+0x1b/0x30
  do_syscall_64+0x1a0/0x4e0
  return_from_SYSCALL_64+0x0/0x7a
 INFO: Slab 0xffffea0011503600 objects=7 used=7 fp=0x          (null) flags=0x8000000000004080
 INFO: Object 0xffff8804540de848 @offset=26696 fp=0xffff8804540dc588
 Redzone ffff8804540de840: bb bb bb bb bb bb bb bb                          ........
 Object ffff8804540de848: 6b 6b 6b 6b 6b 6b 6b 6b b5 52 00 00 f2 01 60 cc  kkkkkkkk.R....`.

Similarly, poisoning after the quarantine_put() leads to false positive
use-after-free reports:

 BUG: KASAN: use-after-free in anon_vma_interval_tree_insert+0x304/0x430 at addr ffff880405c540a0
 Read of size 8 by task trinity-c0/3036
 CPU: 0 PID: 3036 Comm: trinity-c0 Not tainted 4.7.0-think+ #9
 Call Trace:
   dump_stack+0x68/0x96
   kasan_report_error+0x222/0x600
   __asan_report_load8_noabort+0x61/0x70
   anon_vma_interval_tree_insert+0x304/0x430
   anon_vma_chain_link+0x91/0xd0
   anon_vma_clone+0x136/0x3f0
   anon_vma_fork+0x81/0x4c0
   copy_process.part.47+0x2c43/0x5b20
   _do_fork+0x16d/0xbd0
   SyS_clone+0x19/0x20
   do_syscall_64+0x1a0/0x4e0
   entry_SYSCALL64_slow_path+0x25/0x25

Fix this by putting an object in the quarantine after all other
operations.

Fixes: 80a9201a59 ("mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB")
Link: http://lkml.kernel.org/r/1470062715-14077-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Sasha Levin <alexander.levin@verizon.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 17:31:41 -04:00
Alexander Potapenko
80a9201a59 mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB
For KASAN builds:
 - switch SLUB allocator to using stackdepot instead of storing the
   allocation/deallocation stacks in the objects;
 - change the freelist hook so that parts of the freelist can be put
   into the quarantine.

[aryabinin@virtuozzo.com: fixes]
  Link: http://lkml.kernel.org/r/1468601423-28676-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1468347165-41906-3-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Joonsoo Kim
0ab686d8c8 kasan/quarantine: fix bugs on qlist_move_cache()
There are two bugs on qlist_move_cache().  One is that qlist's tail
isn't set properly.  curr->next can be NULL since it is singly linked
list and NULL value on tail is invalid if there is one item on qlist.
Another one is that if cache is matched, qlist_put() is called and it
will set curr->next to NULL.  It would cause to stop the loop
prematurely.

These problems come from complicated implementation so I'd like to
re-implement it completely.  Implementation in this patch is really
simple.  Iterate all qlist_nodes and put them to appropriate list.

Unfortunately, I got this bug sometime ago and lose oops message.  But,
the bug looks trivial and no need to attach oops.

Fixes: 55834c5909 ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/1467766348-22419-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Kuthonuzo Luruo <poll.stdin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-15 14:54:27 +09:00
Andrey Ryabinin
9b75a867cc mm: mempool: kasan: don't poot mempool objects in quarantine
Currently we may put reserved by mempool elements into quarantine via
kasan_kfree().  This is totally wrong since quarantine may really free
these objects.  So when mempool will try to use such element,
use-after-free will happen.  Or mempool may decide that it no longer
need that element and double-free it.

So don't put object into quarantine in kasan_kfree(), just poison it.
Rename kasan_kfree() to kasan_poison_kfree() to respect that.

Also, we shouldn't use kasan_slab_alloc()/kasan_krealloc() in
kasan_unpoison_element() because those functions may update allocation
stacktrace.  This would be wrong for the most of the remove_element call
sites.

(The only call site where we may want to update alloc stacktrace is
 in mempool_alloc(). Kmemleak solves this by calling
 kmemleak_update_trace(), so we could make something like that too.
 But this is out of scope of this patch).

Fixes: 55834c5909 ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/575977C3.1010905@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24 17:23:52 -07:00
Shuah Khan
91a4c27214 kasan: change memory hot-add error messages to info messages
Change the following memory hot-add error messages to info messages.
There is no need for these to be errors.

   kasan: WARNING: KASAN doesn't support memory hot-add
   kasan: Memory hot-add will be disabled

Link: http://lkml.kernel.org/r/1464794430-5486-1-git-send-email-shuahkh@osg.samsung.com
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-09 14:23:11 -07:00
Andrey Ryabinin
9725759a96 mm: kasan: remove unused 'reserved' field from struct kasan_alloc_meta
Commit cd11016e5f ("mm, kasan: stackdepot implementation.  Enable
stackdepot for SLAB") added 'reserved' field, but never used it.

Link: http://lkml.kernel.org/r/1464021054-2307-1-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-26 15:35:44 -07:00
Andrey Ryabinin
64f8ebaf11 mm/kasan: add API to check memory regions
Memory access coded in an assembly won't be seen by KASAN as a compiler
can instrument only C code.  Add kasan_check_[read,write]() API which is
going to be used to check a certain memory range.

Link: http://lkml.kernel.org/r/1462538722-1574-3-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
Andrey Ryabinin
936bb4bbbb mm/kasan: print name of mem[set,cpy,move]() caller in report
When bogus memory access happens in mem[set,cpy,move]() it's usually
caller's fault.  So don't blame mem[set,cpy,move]() in bug report, blame
the caller instead.

Before:
  BUG: KASAN: out-of-bounds access in memset+0x23/0x40 at <address>
After:
  BUG: KASAN: out-of-bounds access in <memset_caller> at <address>

Link: http://lkml.kernel.org/r/1462538722-1574-2-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
Alexander Potapenko
55834c5909 mm: kasan: initial memory quarantine implementation
Quarantine isolates freed objects in a separate queue.  The objects are
returned to the allocator later, which helps to detect use-after-free
errors.

When the object is freed, its state changes from KASAN_STATE_ALLOC to
KASAN_STATE_QUARANTINE.  The object is poisoned and put into quarantine
instead of being returned to the allocator, therefore every subsequent
access to that object triggers a KASAN error, and the error handler is
able to say where the object has been allocated and deallocated.

When it's time for the object to leave quarantine, its state becomes
KASAN_STATE_FREE and it's returned to the allocator.  From now on the
allocator may reuse it for another allocation.  Before that happens,
it's still possible to detect a use-after free on that object (it
retains the allocation/deallocation stacks).

When the allocator reuses this object, the shadow is unpoisoned and old
allocation/deallocation stacks are wiped.  Therefore a use of this
object, even an incorrect one, won't trigger ASan warning.

Without the quarantine, it's not guaranteed that the objects aren't
reused immediately, that's why the probability of catching a
use-after-free is lower than with quarantine in place.

Quarantine isolates freed objects in a separate queue.  The objects are
returned to the allocator later, which helps to detect use-after-free
errors.

Freed objects are first added to per-cpu quarantine queues.  When a
cache is destroyed or memory shrinking is requested, the objects are
moved into the global quarantine queue.  Whenever a kmalloc call allows
memory reclaiming, the oldest objects are popped out of the global queue
until the total size of objects in quarantine is less than 3/4 of the
maximum quarantine size (which is a fraction of installed physical
memory).

As long as an object remains in the quarantine, KASAN is able to report
accesses to it, so the chance of reporting a use-after-free is
increased.  Once the object leaves quarantine, the allocator may reuse
it, in which case the object is unpoisoned and KASAN can't detect
incorrect accesses to it.

Right now quarantine support is only enabled in SLAB allocator.
Unification of KASAN features in SLAB and SLUB will be done later.

This patch is based on the "mm: kasan: quarantine" patch originally
prepared by Dmitry Chernenkov.  A number of improvements have been
suggested by Andrey Ryabinin.

[glider@google.com: v9]
  Link: http://lkml.kernel.org/r/1462987130-144092-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00
Alexander Potapenko
0b355eaaaa mm, kasan: fix compilation for CONFIG_SLAB
Add the missing argument to set_track().

Fixes: cd11016e5f ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 17:03:37 -05:00
Alexander Potapenko
cd11016e5f mm, kasan: stackdepot implementation. Enable stackdepot for SLAB
Implement the stack depot and provide CONFIG_STACKDEPOT.  Stack depot
will allow KASAN store allocation/deallocation stack traces for memory
chunks.  The stack traces are stored in a hash table and referenced by
handles which reside in the kasan_alloc_meta and kasan_free_meta
structures in the allocated memory chunks.

IRQ stack traces are cut below the IRQ entry point to avoid unnecessary
duplication.

Right now stackdepot support is only enabled in SLAB allocator.  Once
KASAN features in SLAB are on par with those in SLUB we can switch SLUB
to stackdepot as well, thus removing the dependency on SLUB stack
bookkeeping, which wastes a lot of memory.

This patch is based on the "mm: kasan: stack depots" patch originally
prepared by Dmitry Chernenkov.

Joonsoo has said that he plans to reuse the stackdepot code for the
mm/page_owner.c debugging facility.

[akpm@linux-foundation.org: s/depot_stack_handle/depot_stack_handle_t]
[aryabinin@virtuozzo.com: comment style fixes]
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00
Alexander Potapenko
505f5dcb1c mm, kasan: add GFP flags to KASAN API
Add GFP flags to KASAN hooks for future patches to use.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00
Alexander Potapenko
7ed2f9e663 mm, kasan: SLAB support
Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00
Dmitry Vyukov
5c9a8750a6 kernel: add kcov code coverage
kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing).  Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system.  A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/).  However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.

kcov does not aim to collect as much coverage as possible.  It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g.  scheduler, locking).

Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes.  Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch).  I've
dropped the second mode for simplicity.

This patch adds the necessary support on kernel side.  The complimentary
compiler support was added in gcc revision 231296.

We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:

  https://github.com/google/syzkaller/wiki/Found-Bugs

We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation".  For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.

Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
typical coverage can be just a dozen of basic blocks (e.g.  an invalid
input).  In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M).  Cost of
kcov depends only on number of executed basic blocks/edges.  On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.

kcov exposes kernel PCs and control flow to user-space which is
insecure.  But debugfs should not be mapped as user accessible.

Based on a patch by Quentin Casasnovas.

[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22 15:36:02 -07:00
Joe Perches
756a025f00 mm: coalesce split strings
Kernel style prefers a single string over split strings when the string is
'user-visible'.

Miscellanea:

 - Add a missing newline
 - Realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Tejun Heo <tj@kernel.org>	[percpu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Mark Rutland
e3ae116339 kasan: add functions to clear stack poison
Functions which the compiler has instrumented for ASAN place poison on
the stack shadow upon entry and remove this poison prior to returning.

In some cases (e.g. hotplug and idle), CPUs may exit the kernel a
number of levels deep in C code.  If there are any instrumented
functions on this critical path, these will leave portions of the idle
thread stack shadow poisoned.

If a CPU returns to the kernel via a different path (e.g. a cold
entry), then depending on stack frame layout subsequent calls to
instrumented functions may use regions of the stack with stale poison,
resulting in (spurious) KASAN splats to the console.

Contemporary GCCs always add stack shadow poisoning when ASAN is
enabled, even when asked to not instrument a function [1], so we can't
simply annotate functions on the critical path to avoid poisoning.

Instead, this series explicitly removes any stale poison before it can
be hit.  In the common hotplug case we clear the entire stack shadow in
common code, before a CPU is brought online.

On architectures which perform a cold return as part of cpu idle may
retain an architecture-specific amount of stack contents.  To retain the
poison for this retained context, the arch code must call the core KASAN
code, passing a "watermark" stack pointer value beyond which shadow will
be cleared.  Architectures which don't perform a cold return as part of
idle do not need any additional code.

This patch (of 3):

Functions which the compiler has instrumented for KASAN place poison on
the stack shadow upon entry and remove this poision prior to returning.

In some cases (e.g.  hotplug and idle), CPUs may exit the kernel a number
of levels deep in C code.  If there are any instrumented functions on this
critical path, these will leave portions of the stack shadow poisoned.

If a CPU returns to the kernel via a different path (e.g.  a cold entry),
then depending on stack frame layout subsequent calls to instrumented
functions may use regions of the stack with stale poison, resulting in
(spurious) KASAN splats to the console.

To avoid this, we must clear stale poison from the stack prior to
instrumented functions being called.  This patch adds functions to the
KASAN core for removing poison from (portions of) a task's stack.  These
will be used by subsequent patches to avoid problems with hotplug and
idle.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-09 15:43:42 -08:00
Andrey Ryabinin
c6d308534a UBSAN: run-time undefined behavior sanity checker
UBSAN uses compile-time instrumentation to catch undefined behavior
(UB).  Compiler inserts code that perform certain kinds of checks before
operations that could cause UB.  If check fails (i.e.  UB detected)
__ubsan_handle_* function called to print error message.

So the most of the work is done by compiler.  This patch just implements
ubsan handlers printing errors.

GCC has this capability since 4.9.x [1] (see -fsanitize=undefined
option and its suboptions).
However GCC 5.x has more checkers implemented [2].
Article [3] has a bit more details about UBSAN in the GCC.

[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
[3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/

Issues which UBSAN has found thus far are:

Found bugs:

 * out-of-bounds access - 97840cb67f ("netfilter: nfnetlink: fix
   insufficient validation in nfnetlink_bind")

undefined shifts:

 * d48458d4a7 ("jbd2: use a better hash function for the revoke
   table")

 * 10632008b9 ("clockevents: Prevent shift out of bounds")

 * 'x << -1' shift in ext4 -
   http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com>

 * undefined rol32(0) -
   http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com>

 * undefined dirty_ratelimit calculation -
   http://lkml.kernel.org/r/<566594E2.3050306@odin.com>

 * undefined roundown_pow_of_two(0) -
   http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com>

 * [WONTFIX] undefined shift in __bpf_prog_run -
   http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com>

   WONTFIX here because it should be fixed in bpf program, not in kernel.

signed overflows:

 * 32a8df4e0b ("sched: Fix odd values in effective_load()
   calculations")

 * mul overflow in ntp -
   http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com>

 * incorrect conversion into rtc_time in rtc_time64_to_tm() -
   http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com>

 * unvalidated timespec in io_getevents() -
   http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com>

 * [NOTABUG] signed overflow in ktime_add_safe() -
   http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com>

[akpm@linux-foundation.org: fix unused local warning]
[akpm@linux-foundation.org: fix __int128 build woes]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yury Gribov <y.gribov@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20 17:09:18 -08:00
Andrey Ryabinin
459372545c kasan: fix kmemleak false-positive in kasan_module_alloc()
Kmemleak reports the following leak:

	unreferenced object 0xfffffbfff41ea000 (size 20480):
	comm "modprobe", pid 65199, jiffies 4298875551 (age 542.568s)
	hex dump (first 32 bytes):
	  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
	  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
	backtrace:
	  [<ffffffff82354f5e>] kmemleak_alloc+0x4e/0xc0
	  [<ffffffff8152e718>] __vmalloc_node_range+0x4b8/0x740
	  [<ffffffff81574072>] kasan_module_alloc+0x72/0xc0
	  [<ffffffff810efe68>] module_alloc+0x78/0xb0
	  [<ffffffff812f6a24>] module_alloc_update_bounds+0x14/0x70
	  [<ffffffff812f8184>] layout_and_allocate+0x16f4/0x3c90
	  [<ffffffff812faa1f>] load_module+0x2ff/0x6690
	  [<ffffffff813010b6>] SyS_finit_module+0x136/0x170
	  [<ffffffff8239bbc9>] system_call_fastpath+0x16/0x1b
	  [<ffffffffffffffff>] 0xffffffffffffffff

kasan_module_alloc() allocates shadow memory for module and frees it on
module unloading.  It doesn't store the pointer to allocated shadow memory
because it could be calculated from the shadowed address, i.e.
kasan_mem_to_shadow(addr).

Since kmemleak cannot find pointer to allocated shadow, it thinks that
memory leaked.

Use kmemleak_ignore() to tell kmemleak that this is not a leak and shadow
memory doesn't contain any pointers.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-20 16:17:32 -08:00
Andrey Ryabinin
eb06f43f1c kasan: always taint kernel on report
Currently we already taint the kernel in some cases.  E.g.  if we hit some
bug in slub memory we call object_err() which will taint the kernel with
TAINT_BAD_PAGE flag.  But for other kind of bugs kernel left untainted.

Always taint with TAINT_BAD_PAGE if kasan found some bug.  This is useful
for automated testing.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Xishi Qiu
10f702627e kasan: use IS_ALIGNED in memory_is_poisoned_8()
Use IS_ALIGNED() to determine whether the shadow span two bytes.  It
generates less code and more readable.  Also add some comments in shadow
check functions.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Wang Long
e0d5771439 kasan: Fix a type conversion error
The current KASAN code can not find the following out-of-bounds bugs:

        char *ptr;
        ptr = kmalloc(8, GFP_KERNEL);
        memset(ptr+7, 0, 2);

the cause of the problem is the type conversion error in
*memory_is_poisoned_n* function.  So this patch fix that.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Andrey Konovalov
5d0926efe7 kasan: update reference to kasan prototype repo
Update the reference to the kasan prototype repository on github, since it
was renamed.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Andrey Konovalov
25add7ec70 kasan: update log messages
We decided to use KASAN as the short name of the tool and
KernelAddressSanitizer as the full one.  Update log messages according to
that.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Andrey Konovalov
cdf6a273dc kasan: accurately determine the type of the bad access
Makes KASAN accurately determine the type of the bad access. If the shadow
byte value is in the [0, KASAN_SHADOW_SCALE_SIZE) range we can look at
the next shadow byte to determine the type of the access.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Andrey Konovalov
0952d87fd6 kasan: update reported bug types for kernel memory accesses
Update the names of the bad access types to better reflect the type of
the access that happended and make these error types "literals" that can
be used for classification and deduplication in scripts.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Andrey Konovalov
e912107663 kasan: update reported bug types for not user nor kernel memory accesses
Each access with address lower than
kasan_shadow_to_mem(KASAN_SHADOW_START) is reported as user-memory-access.
This is not always true, the accessed address might not be in user space.
Fix this by reporting such accesses as null-ptr-derefs or
wild-memory-accesses.

There's another reason for this change.  For userspace ASan we have a
bunch of systems that analyze error types for the purpose of
classification and deduplication.  Sooner of later we will write them to
KASAN as well.  Then clearly and explicitly stated error types will bring
value.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Aneesh Kumar K.V
fc5aeeaf59 mm/kasan: prevent deadlock in kasan reporting
When we end up calling kasan_report in real mode, our shadow mapping for
the spinlock variable will show poisoned.  This will result in us calling
kasan_report_error with lock_report spin lock held.  To prevent this
disable kasan reporting when we are priting error w.r.t kasan.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Aneesh Kumar K.V
f2377d4eaa mm/kasan: don't use kasan shadow pointer in generic functions
We can't use generic functions like print_hex_dump to access kasan shadow
region.  This require us to setup another kasan shadow region for the
address passed (kasan shadow address).  Some architectures won't be able
to do that.  Hence make a copy of the shadow region row and pass that to
generic functions.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Aneesh Kumar K.V
527f215b78 mm/kasan: MODULE_VADDR is not available on all archs
Use is_module_address instead

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Aneesh Kumar K.V
0ba8663cbf mm/kasan: rename kasan_enabled() to kasan_report_enabled()
The function only disable/enable reporting.  In the later patch we will be
adding a kasan early enable/disable.  Rename kasan_enabled to properly
reflect its function.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05 19:34:48 -08:00
Xishi Qiu
8d77a6d18a kasan: fix last shadow judgement in memory_is_poisoned_16()
The shadow which correspond 16 bytes memory may span 2 or 3 bytes.  If
the memory is aligned on 8, then the shadow takes only 2 bytes.  So we
check "shadow_first_bytes" is enough, and need not to call
"memory_is_poisoned_1(addr + 15);".  But the code "if
(likely(!last_byte))" is wrong judgement.

e.g.  addr=0, so last_byte = 15 & KASAN_SHADOW_MASK = 7, then the code
will continue to call "memory_is_poisoned_1(addr + 15);"

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.cz>
Cc: <zhongjiang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-17 21:16:07 -07:00
Andrey Ryabinin
69786cdb37 x86/kasan, mm: Introduce generic kasan_populate_zero_shadow()
Introduce generic kasan_populate_zero_shadow(shadow_start,
shadow_end). This function maps kasan_zero_page to the
[shadow_start, shadow_end] addresses.

This replaces x86_64 specific populate_zero_shadow() and will
be used for ARM64 in follow on patches.

The main changes from original version are:

 * Use p?d_populate*() instead of set_p?d()
 * Use memblock allocator directly instead of vmemmap_alloc_block()
 * __pa() instead of __pa_nodebug(). __pa() causes troubles
   iff we use it before kasan_early_init(). kasan_populate_zero_shadow()
   will be used later, so we ok with __pa() here.

Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Keitel <dkeitel@codeaurora.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yury <yury.norov@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1439444244-26057-3-git-send-email-ryabinin.a.a@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-22 14:54:55 +02:00
Andrey Ryabinin
2baf9e8948 .mailmap: Andrey Ryabinin has moved
Update my email address.

Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-14 15:56:32 -07:00
Wang Long
bffacb9132 kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
Remove duplicate definition of the macro KASAN_FREE_PAGE in
mm/kasan/kasan.h

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:42 -07:00
Andrey Ryabinin
923936157b mm/mempool.c: kasan: poison mempool elements
Mempools keep allocated objects in reserved for situations when ordinary
allocation may not be possible to satisfy.  These objects shouldn't be
accessed before they leave the pool.

This patch poison elements when get into the pool and unpoison when they
leave it.  This will let KASan to detect use-after-free of mempool's
elements.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Tested-by: David Rientjes <rientjes@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Chernenkov <drcheren@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 16:35:20 -07:00
Andrey Ryabinin
a5af5aa8b6 kasan, module, vmalloc: rework shadow allocation for modules
Current approach in handling shadow memory for modules is broken.

Shadow memory could be freed only after memory shadow corresponds it is no
longer used.  vfree() called from interrupt context could use memory its
freeing to store 'struct llist_node' in it:

    void vfree(const void *addr)
    {
    ...
        if (unlikely(in_interrupt())) {
            struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
            if (llist_add((struct llist_node *)addr, &p->list))
                    schedule_work(&p->wq);

Later this list node used in free_work() which actually frees memory.
Currently module_memfree() called in interrupt context will free shadow
before freeing module's memory which could provoke kernel crash.

So shadow memory should be freed after module's memory.  However, such
deallocation order could race with kasan_module_alloc() in module_alloc().

Free shadow right before releasing vm area.  At this point vfree()'d
memory is not used anymore and yet not available for other allocations.
New VM_KASAN flag used to indicate that vm area has dynamically allocated
shadow memory so kasan frees shadow only if it was previously allocated.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-12 18:46:08 -07:00
Andrey Ryabinin
bebf56a1b1 kasan: enable instrumentation of global variables
This feature let us to detect accesses out of bounds of global variables.
This will work as for globals in kernel image, so for globals in modules.
Currently this won't work for symbols in user-specified sections (e.g.
__init, __read_mostly, ...)

The idea of this is simple.  Compiler increases each global variable by
redzone size and add constructors invoking __asan_register_globals()
function.  Information about global variable (address, size, size with
redzone ...) passed to __asan_register_globals() so we could poison
variable's redzone.

This patch also forces module_alloc() to return 8*PAGE_SIZE aligned
address making shadow memory handling (
kasan_module_alloc()/kasan_module_free() ) more simple.  Such alignment
guarantees that each shadow page backing modules address space correspond
to only one module_alloc() allocation.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:42 -08:00
Andrey Ryabinin
c420f167db kasan: enable stack instrumentation
Stack instrumentation allows to detect out of bounds memory accesses for
variables allocated on stack.  Compiler adds redzones around every
variable on stack and poisons redzones in function's prologue.

Such approach significantly increases stack usage, so all in-kernel stacks
size were doubled.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:41 -08:00
Andrey Ryabinin
393f203f5f x86_64: kasan: add interceptors for memset/memmove/memcpy functions
Recently instrumentation of builtin functions calls was removed from GCC
5.0.  To check the memory accessed by such functions, userspace asan
always uses interceptors for them.

So now we should do this as well.  This patch declares
memset/memmove/memcpy as weak symbols.  In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.

Default memset/memmove/memcpy now now always have aliases with '__'
prefix.  For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:41 -08:00
Andrey Ryabinin
0316bec22e mm: slub: add kernel address sanitizer support for slub allocator
With this patch kasan will be able to catch bugs in memory allocated by
slub.  Initially all objects in newly allocated slab page, marked as
redzone.  Later, when allocation of slub object happens, requested by
caller number of bytes marked as accessible, and the rest of the object
(including slub's metadata) marked as redzone (inaccessible).

We also mark object as accessible if ksize was called for this object.
There is some places in kernel where ksize function is called to inquire
size of really allocated area.  Such callers could validly access whole
allocated memory, so it should be marked as accessible.

Code in slub.c and slab_common.c files could validly access to object's
metadata, so instrumentation for this files are disabled.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Dmitry Chernenkov <dmitryc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:41 -08:00
Andrey Ryabinin
b8c73fc249 mm: page_alloc: add kasan hooks on alloc and free paths
Add kernel address sanitizer hooks to mark allocated page's addresses as
accessible in corresponding shadow region.  Mark freed pages as
inaccessible.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:41 -08:00
Andrey Ryabinin
786a895991 kasan: disable memory hotplug
Currently memory hotplug won't work with KASan.  As we don't have shadow
for hotplugged memory, kernel will crash on the first access to it.  To
make this work we will need to allocate shadow for new memory.

At some future point proper memory hotplug support will be implemented.
Until then, print a warning at startup and disable memory hot-add.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:40 -08:00
Andrey Ryabinin
0b24becc81 kasan: add kernel address sanitizer infrastructure
Kernel Address sanitizer (KASan) is a dynamic memory error detector.  It
provides fast and comprehensive solution for finding use-after-free and
out-of-bounds bugs.

KASAN uses compile-time instrumentation for checking every memory access,
therefore GCC > v4.9.2 required.  v4.9.2 almost works, but has issues with
putting symbol aliases into the wrong section, which breaks kasan
instrumentation of globals.

This patch only adds infrastructure for kernel address sanitizer.  It's
not available for use yet.  The idea and some code was borrowed from [1].

Basic idea:

The main idea of KASAN is to use shadow memory to record whether each byte
of memory is safe to access or not, and use compiler's instrumentation to
check the shadow memory on each memory access.

Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
memory and uses direct mapping with a scale and offset to translate a
memory address to its corresponding shadow address.

Here is function to translate address to corresponding shadow address:

     unsigned long kasan_mem_to_shadow(unsigned long addr)
     {
                return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET;
     }

where KASAN_SHADOW_SCALE_SHIFT = 3.

So for every 8 bytes there is one corresponding byte of shadow memory.
The following encoding used for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are valid for access; k (1 <= k <= 7)
means that the first k bytes are valid for access, and other (8 - k) bytes
are not; Any negative value indicates that the entire 8-bytes are
inaccessible.  Different negative values used to distinguish between
different kinds of inaccessible memory (redzones, freed memory) (see
mm/kasan/kasan.h).

To be able to detect accesses to bad memory we need a special compiler.
Such compiler inserts a specific function calls (__asan_load*(addr),
__asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.

These functions check whether memory region is valid to access or not by
checking corresponding shadow memory.  If access is not valid an error
printed.

Historical background of the address sanitizer from Dmitry Vyukov:

	"We've developed the set of tools, AddressSanitizer (Asan),
	ThreadSanitizer and MemorySanitizer, for user space. We actively use
	them for testing inside of Google (continuous testing, fuzzing,
	running prod services). To date the tools have found more than 10'000
	scary bugs in Chromium, Google internal codebase and various
	open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and
	lots of others): [2] [3] [4].
	The tools are part of both gcc and clang compilers.

	We have not yet done massive testing under the Kernel AddressSanitizer
	(it's kind of chicken and egg problem, you need it to be upstream to
	start applying it extensively). To date it has found about 50 bugs.
	Bugs that we've found in upstream kernel are listed in [5].
	We've also found ~20 bugs in out internal version of the kernel. Also
	people from Samsung and Oracle have found some.

	[...]

	As others noted, the main feature of AddressSanitizer is its
	performance due to inline compiler instrumentation and simple linear
	shadow memory. User-space Asan has ~2x slowdown on computational
	programs and ~2x memory consumption increase. Taking into account that
	kernel usually consumes only small fraction of CPU and memory when
	running real user-space programs, I would expect that kernel Asan will
	have ~10-30% slowdown and similar memory consumption increase (when we
	finish all tuning).

	I agree that Asan can well replace kmemcheck. We have plans to start
	working on Kernel MemorySanitizer that finds uses of unitialized
	memory. Asan+Msan will provide feature-parity with kmemcheck. As
	others noted, Asan will unlikely replace debug slab and pagealloc that
	can be enabled at runtime. Asan uses compiler instrumentation, so even
	if it is disabled, it still incurs visible overheads.

	Asan technology is easily portable to other architectures. Compiler
	instrumentation is fully portable. Runtime has some arch-dependent
	parts like shadow mapping and atomic operation interception. They are
	relatively easy to port."

Comparison with other debugging features:
========================================

KMEMCHECK:

  - KASan can do almost everything that kmemcheck can.  KASan uses
    compile-time instrumentation, which makes it significantly faster than
    kmemcheck.  The only advantage of kmemcheck over KASan is detection of
    uninitialized memory reads.

    Some brief performance testing showed that kasan could be
    x500-x600 times faster than kmemcheck:

$ netperf -l 30
		MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET
		Recv   Send    Send
		Socket Socket  Message  Elapsed
		Size   Size    Size     Time     Throughput
		bytes  bytes   bytes    secs.    10^6bits/sec

no debug:	87380  16384  16384    30.00    41624.72

kasan inline:	87380  16384  16384    30.00    12870.54

kasan outline:	87380  16384  16384    30.00    10586.39

kmemcheck: 	87380  16384  16384    30.03      20.23

  - Also kmemcheck couldn't work on several CPUs.  It always sets
    number of CPUs to 1.  KASan doesn't have such limitation.

DEBUG_PAGEALLOC:
	- KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page
	  granularity level, so it able to find more bugs.

SLUB_DEBUG (poisoning, redzones):
	- SLUB_DEBUG has lower overhead than KASan.

	- SLUB_DEBUG in most cases are not able to detect bad reads,
	  KASan able to detect both reads and writes.

	- In some cases (e.g. redzone overwritten) SLUB_DEBUG detect
	  bugs only on allocation/freeing of object. KASan catch
	  bugs right before it will happen, so we always know exact
	  place of first bad read/write.

[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
[2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs
[3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs
[4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs
[5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies

Based on work by Andrey Konovalov.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-13 21:21:40 -08:00