Commit graph

266 commits

Author SHA1 Message Date
Linus Torvalds
996fe06160 kgdb patches for 5.15
Changes for kgdb/kdb this cycle are dominated by a change from
 Sumit that removes as small (256K) private heap from kdb. This is
 change I've hoped for ever since I discovered how few users of this
 heap remained in the kernel, so many thanks to Sumit for hunting
 these down. Other change is an incremental step towards SPDX headers.
 
 Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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Merge tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

Pull kgdb updates from Daniel Thompson:
 "Changes for kgdb/kdb this cycle are dominated by a change from Sumit
  that removes as small (256K) private heap from kdb. This is change
  I've hoped for ever since I discovered how few users of this heap
  remained in the kernel, so many thanks to Sumit for hunting these
  down.

  The other change is an incremental step towards SPDX headers"

* tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kernel: debug: Convert to SPDX identifier
  kdb: Rename members of struct kdbtab_t
  kdb: Simplify kdb_defcmd macro logic
  kdb: Get rid of redundant kdb_register_flags()
  kdb: Rename struct defcmd_set to struct kdb_macro
  kdb: Get rid of custom debug heap allocator
2021-09-07 12:08:04 -07:00
Cai Huoqing
f8416aa291 kernel: debug: Convert to SPDX identifier
use SPDX-License-Identifier instead of a verbose license text

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20210906112302.937-1-caihuoqing@baidu.com
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-09-06 14:31:11 +01:00
Alexey Dobriyan
39f75da7bc isystem: trim/fixup stdarg.h and other headers
Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-19 09:02:55 +09:00
Sumit Garg
e868f0a3c4 kdb: Rename members of struct kdbtab_t
Remove redundant prefix "cmd_" from name of members in struct kdbtab_t
for better readibility.

Suggested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-5-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27 17:05:06 +01:00
Sumit Garg
9a5db530aa kdb: Simplify kdb_defcmd macro logic
Switch to use a linked list instead of dynamic array which makes
allocation of kdb macro and traversing the kdb macro commands list
simpler.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-4-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27 17:04:50 +01:00
Sumit Garg
c25abcd625 kdb: Get rid of redundant kdb_register_flags()
Commit e4f291b3f7 ("kdb: Simplify kdb commands registration")
allowed registration of pre-allocated kdb commands with pointer to
struct kdbtab_t. Lets switch other users as well to register pre-
allocated kdb commands via:
- Changing prototype for kdb_register() to pass a pointer to struct
  kdbtab_t instead.
- Embed kdbtab_t structure in kdb_macro_t rather than individual params.

With these changes kdb_register_flags() becomes redundant and hence
removed. Also, since we have switched all users to register
pre-allocated commands, "is_dynamic" flag in struct kdbtab_t becomes
redundant and hence removed as well.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-3-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27 17:03:16 +01:00
Sumit Garg
b39cded834 kdb: Rename struct defcmd_set to struct kdb_macro
Rename struct defcmd_set to struct kdb_macro as that sounds more
appropriate given its purpose.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210712134620.276667-2-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27 17:00:14 +01:00
Sumit Garg
95f7f15461 kdb: Get rid of custom debug heap allocator
Currently the only user for debug heap is kdbnearsym() which can be
modified to rather use statically allocated buffer for symbol name as
per it's current usage. So do that and hence remove custom debug heap
allocator.

Note that this change puts a restriction on kdbnearsym() callers to
carefully use shared namebuf such that a caller should consume the symbol
returned immediately prior to another call to fetch a different symbol.

Also, this change uses standard KSYM_NAME_LEN macro for namebuf
allocation instead of local variable: knt1_size which should avoid any
conflicts caused by changes to KSYM_NAME_LEN macro value.

This change has been tested using kgdbtest on arm64 which doesn't show
any regressions.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210714055620.369915-1-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27 14:46:11 +01:00
Gustavo A. R. Silva
1adee589cd kernel: debug: Fix unreachable code in gdb_serial_stub()
Fix the following warning:

kernel/debug/gdbstub.c:1049:4: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
                           fallthrough;
                           ^
   include/linux/compiler_attributes.h:210:41: note: expanded from macro 'fallthrough'
   # define fallthrough                    __attribute__((__fallthrough__)

by placing the fallthrough; statement inside ifdeffery.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-07-12 11:03:35 -05:00
Linus Torvalds
df8ba5f160 kgdb patches for 5.14
This was a extremely quiet cycle for kgdb. This PR consists of two
 patches that between them address spelling errors and a switch
 fallthrough warning.
 
 Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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Merge tag 'kgdb-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

Pull kgdb updates from Daniel Thompson:
 "This was a extremely quiet cycle for kgdb. This consists of two
  patches that between them address spelling errors and a switch
  fallthrough warning"

* tag 'kgdb-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kgdb: Fix fall-through warning for Clang
  kgdb: Fix spelling mistakes
2021-07-06 11:29:18 -07:00
Linus Torvalds
e563592c3e printk changes for 5.14
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Merge tag 'printk-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Add %pt[RT]s modifier to vsprintf(). It overrides ISO 8601 separator
   by using ' ' (space). It produces "YYYY-mm-dd HH:MM:SS" instead of
   "YYYY-mm-ddTHH:MM:SS".

 - Correctly parse long row of numbers by sscanf() when using the field
   width. Add extensive sscanf() selftest.

 - Generalize re-entrant CPU lock that has already been used to
   serialize dump_stack() output. It is part of the ongoing printk
   rework. It will allow to remove the obsoleted printk_safe buffers and
   introduce atomic consoles.

 - Some code clean up and sparse warning fixes.

* tag 'printk-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: fix cpu lock ordering
  lib/dump_stack: move cpu lock to printk.c
  printk: Remove trailing semicolon in macros
  random32: Fix implicit truncation warning in prandom_seed_state()
  lib: test_scanf: Remove pointless use of type_min() with unsigned types
  selftests: lib: Add wrapper script for test_scanf
  lib: test_scanf: Add tests for sscanf number conversion
  lib: vsprintf: Fix handling of number field widths in vsscanf
  lib: vsprintf: scanf: Negative number must have field width > 1
  usb: host: xhci-tegra: Switch to use %ptTs
  nilfs2: Switch to use %ptTs
  kdb: Switch to use %ptTs
  lib/vsprintf: Allow to override ISO 8601 date and time separator
2021-06-29 12:07:18 -07:00
Peter Zijlstra
2f064a59a1 sched: Change task_struct::state
Change the type and name of task_struct::state. Drop the volatile and
shrink it to an 'unsigned int'. Rename it in order to find all uses
such that we can use READ_ONCE/WRITE_ONCE as appropriate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org
2021-06-18 11:43:09 +02:00
Gustavo A. R. Silva
c8daba4640 kgdb: Fix fall-through warning for Clang
In preparation to enable -Wimplicit-fallthrough for Clang, fix a
fall-through warning by explicitly adding a goto statement instead
of letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20210528200222.GA39201@embeddedor
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-06-01 10:34:35 +01:00
Zhen Lei
220a31b091 kgdb: Fix spelling mistakes
Fix some spelling mistakes in comments:
initalization ==> initialization
detatch ==> detach
represntation ==> representation
hexidecimal ==> hexadecimal
delimeter ==> delimiter
architecure ==> architecture

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210529110305.9446-3-thunder.leizhen@huawei.com
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-06-01 10:29:21 +01:00
Andy Shevchenko
126ac4d67d kdb: Switch to use %ptTs
Use %ptTs instead of open-coded variant to print contents
of time64_t type in human readable form.

Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: kgdb-bugreport@lists.sourceforge.net
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210511153958.34527-2-andriy.shevchenko@linux.intel.com
2021-05-17 12:01:35 +02:00
Linus Torvalds
7f3d08b255 printk changes for 5.13
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Merge tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Stop synchronizing kernel log buffer readers by logbuf_lock. As a
   result, the access to the buffer is fully lockless now.

   Note that printk() itself still uses locks because it tries to flush
   the messages to the console immediately. Also the per-CPU temporary
   buffers are still there because they prevent infinite recursion and
   serialize backtraces from NMI. All this is going to change in the
   future.

 - kmsg_dump API rework and cleanup as a side effect of the logbuf_lock
   removal.

 - Make bstr_printf() aware that %pf and %pF formats could deference the
   given pointer.

 - Show also page flags by %pGp format.

 - Clarify the documentation for plain pointer printing.

 - Do not show no_hash_pointers warning multiple times.

 - Update Senozhatsky email address.

 - Some clean up.

* tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits)
  lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf()
  printk: clarify the documentation for plain pointer printing
  kernel/printk.c: Fixed mundane typos
  printk: rename vprintk_func to vprintk
  vsprintf: dump full information of page flags in pGp
  mm, slub: don't combine pr_err with INFO
  mm, slub: use pGp to print page flags
  MAINTAINERS: update Senozhatsky email address
  lib/vsprintf: do not show no_hash_pointers message multiple times
  printk: console: remove unnecessary safe buffer usage
  printk: kmsg_dump: remove _nolock() variants
  printk: remove logbuf_lock
  printk: introduce a kmsg_dump iterator
  printk: kmsg_dumper: remove @active field
  printk: add syslog_lock
  printk: use atomic64_t for devkmsg_user.seq
  printk: use seqcount_latch for clear_seq
  printk: introduce CONSOLE_LOG_MAX
  printk: consolidate kmsg_dump_get_buffer/syslog_print_all code
  printk: refactor kmsg_dump_get_buffer()
  ...
2021-04-27 18:09:44 -07:00
Sumit Garg
83fa2d13d6 kdb: Refactor env variables get/set code
Add two new kdb environment access methods as kdb_setenv() and
kdb_printenv() in order to abstract out environment access code
from kdb command functions.

Also, replace (char *)0 with NULL as an initializer for environment
variables array.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/1612771342-16883-1-git-send-email-sumit.garg@linaro.org
[daniel.thompson@linaro.org: Replaced (char *)0/NULL initializers with
an array size]
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-04-14 13:47:09 +01:00
Bhaskar Chowdhury
2bbd9b0f2b kernel: debug: Ordinary typo fixes in the file gdbstub.c
s/overwitten/overwritten/
s/procesing/processing/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Link: https://lore.kernel.org/r/20210317104658.4053473-1-unixbhaskar@gmail.com
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19 17:36:00 +00:00
Sumit Garg
e4f291b3f7 kdb: Simplify kdb commands registration
Simplify kdb commands registration via using linked list instead of
static array for commands storage.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20210224070827.408771-1-sumit.garg@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
[daniel.thompson@linaro.org: Removed a bunch of .cmd_minline = 0
initializers]
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19 16:51:59 +00:00
Sumit Garg
d027fdc4fa kdb: Remove redundant function definitions/prototypes
Cleanup kdb code to get rid of unused function definitions/prototypes.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20210224071653.409150-1-sumit.garg@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19 16:34:52 +00:00
John Ogness
a4f9876532 printk: kmsg_dump: remove _nolock() variants
kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is
no need for _nolock() variants. Remove these functions and switch all
callers of the _nolock() variants.

The functions without _nolock() were chosen because they are already
exported to kernel modules.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-15-john.ogness@linutronix.de
2021-03-08 11:43:35 +01:00
John Ogness
f9f3f02db9 printk: introduce a kmsg_dump iterator
Rather than storing the iterator information in the registered
kmsg_dumper structure, create a separate iterator structure. The
kmsg_dump_iter structure can reside on the stack of the caller, thus
allowing lockless use of the kmsg_dump functions.

Update code that accesses the kernel logs using the kmsg_dumper
structure to use the new kmsg_dump_iter structure. For kmsg_dumpers,
this also means adding a call to kmsg_dump_rewind() to initialize
the iterator.

All this is in preparation for removal of @logbuf_lock.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org> # pstore
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de
2021-03-08 11:43:27 +01:00
John Ogness
5f6c7648e5 printk: kmsg_dumper: remove @active field
All 6 kmsg_dumpers do not benefit from the @active flag:

  (provide their own synchronization)
  - arch/powerpc/kernel/nvram_64.c
  - arch/um/kernel/kmsg_dump.c
  - drivers/mtd/mtdoops.c
  - fs/pstore/platform.c

  (only dump on KMSG_DUMP_PANIC, which does not require
  synchronization)
  - arch/powerpc/platforms/powernv/opal-kmsg.c
  - drivers/hv/vmbus_drv.c

The other 2 kmsg_dump users also do not rely on @active:

  (hard-code @active to always be true)
  - arch/powerpc/xmon/xmon.c
  - kernel/debug/kdb/kdb_main.c

Therefore, @active can be removed.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210303101528.29901-12-john.ogness@linutronix.de
2021-03-08 11:43:23 +01:00
Sumit Garg
d54ce6158e kgdb: fix to kill breakpoints on initmem after boot
Currently breakpoints in kernel .init.text section are not handled
correctly while allowing to remove them even after corresponding pages
have been freed.

Fix it via killing .init.text section breakpoints just prior to initmem
pages being freed.

Doug: "HW breakpoints aren't handled by this patch but it's probably
not such a big deal".

Link: https://lkml.kernel.org/r/20210224081652.587785-1-sumit.garg@linaro.org
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Suggested-by: Doug Anderson <dianders@chromium.org>
Acked-by: Doug Anderson <dianders@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26 09:41:05 -08:00
Daniel Thompson
f11e2bc682 kgdb: Remove kgdb_schedule_breakpoint()
To the very best of my knowledge there has never been any in-tree
code that calls this function. It exists largely to support an
out-of-tree driver that provides kgdb-over-ethernet using the
netpoll API.

kgdboe has been out-of-tree for more than 10 years and I don't
recall any serious attempt to upstream it at any point in the last
five. At this stage it looks better to stop carrying this code in
the kernel and integrate the code into the out-of-tree driver
instead.

The long term trajectory for the kernel looks likely to include
effort to remove or reduce the use of tasklets (something that has
also been true for the last 10 years). Thus the main real reason
for this patch is to make explicit that the in-tree kgdb features
do not require tasklets.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20210210142525.2876648-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
2021-02-11 10:51:56 +00:00
Sumit Garg
93f7a6d818 kdb: Make memory allocations more robust
Currently kdb uses in_interrupt() to determine whether its library
code has been called from the kgdb trap handler or from a saner calling
context such as driver init. This approach is broken because
in_interrupt() alone isn't able to determine kgdb trap handler entry from
normal task context. This can happen during normal use of basic features
such as breakpoints and can also be trivially reproduced using:
echo g > /proc/sysrq-trigger

We can improve this by adding check for in_dbg_master() instead which
explicitly determines if we are running in debugger context.

Cc: stable@vger.kernel.org
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/1611313556-4004-1-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-08 13:42:50 +00:00
Stephen Zhang
0759d80728 kdb: kdb_support: Fix debugging information problem
There are several common patterns.

0:
        kdb_printf("...",...);

which is the normal one.

1:
        kdb_printf("%s: "...,__func__,...)

We could improve '1' to this :

        #define kdb_func_printf(format, args...) \
                kdb_printf("%s: " format, __func__, ## args)

2:
        if(KDB_DEBUG(AR))
                kdb_printf("%s "...,__func__,...);

We could improve '2' to this :
        #define kdb_dbg_printf(mask, format, args...) \
                do { \
                        if (KDB_DEBUG(mask)) \
                                kdb_func_printf(format, ## args); \
                } while (0)

In addition, we changed the format code of size_t to %zu.

Signed-off-by: Stephen Zhang <stephenzhangzsd@gmail.com>
Link: https://lore.kernel.org/r/1612440429-6391-1-git-send-email-stephenzhangzsd@gmail.com
Reviewed-by: Douglas Anderson <dianders@chromium.org>
[daniel.thompson@linaro.org: Minor typo and line length fixes in the
patch description]
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04 15:55:04 +00:00
wengjianfeng
cbd026e1d8 kernel: debug: fix typo issue
change 'regster' to 'register'.

Signed-off-by: wengjianfeng <wengjianfeng@yulong.com>
Link: https://lore.kernel.org/r/20210203081034.9004-1-samirweng1979@163.com
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04 15:26:03 +00:00
Lukas Bulwahn
2da2687b51 kgdb: rectify kernel-doc for kgdb_unregister_io_module()
The command 'find ./kernel/debug/ | xargs ./scripts/kernel-doc -none'
reported a typo in the kernel-doc of kgdb_unregister_io_module().

Rectify the kernel-doc, such that no issues remain for ./kernel/debug/.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20210125144847.21896-1-lukas.bulwahn@gmail.com
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04 15:23:25 +00:00
Peter Zijlstra
545b8c8df4 smp: Cleanup smp_call_function*()
Get rid of the __call_single_node union and cleanup the API a little
to avoid external code relying on the structure layout as much.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
2020-11-24 16:47:49 +01:00
Daniel Thompson
d081a6e353 kdb: Fix pager search for multi-line strings
Currently using forward search doesn't handle multi-line strings correctly.
The search routine replaces line breaks with \0 during the search and, for
regular searches ("help | grep Common\n"), there is code after the line
has been discarded or printed to replace the break character.

However during a pager search ("help\n" followed by "/Common\n") when the
string is matched we will immediately return to normal output and the code
that should restore the \n becomes unreachable. Fix this by restoring the
replaced character when we disable the search mode and update the comment
accordingly.

Fixes: fb6daa7520 ("kdb: Provide forward search at more prompt")
Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-10-01 14:44:08 +01:00
Daniel Thompson
771910f719 kernel: debug: Centralize dbg_[de]activate_sw_breakpoints
During debug trap execution we expect dbg_deactivate_sw_breakpoints()
to be paired with an dbg_activate_sw_breakpoint(). Currently although
the calls are paired correctly they are needlessly smeared across three
different functions. Worse this also results in code to drive polled I/O
being called with breakpoints activated which, in turn, needlessly
increases the set of functions that will recursively trap if breakpointed.

Fix this by moving the activation of breakpoints into the debug core.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200927211531.1380577-4-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-10-01 14:23:45 +01:00
Daniel Thompson
4c4197eda7 kgdb: Add NOKPROBE labels on the trap handler functions
Currently kgdb honours the kprobe blocklist but doesn't place its own
trap handling code on the list. Add labels to discourage attempting to
use kgdb to debug itself.

Not every functions that executes from the trap handler needs to be
marked up: relatively early in the trap handler execution (just after
we bring the other CPUs to a halt) all breakpoints are replaced with
the original opcodes. This patch marks up code in the debug_core that
executes between trap entry and the breakpoints being deactivated
and, also, code that executes between breakpoint activation and trap
exit.

To be clear these changes are not sufficient to make recursive trapping
impossible since they do not include library calls made during kgdb's
entry/exit logic. However going much further whilst we are sharing the
kprobe blocklist risks reducing the capabilities of kprobe and this
would be a bad trade off (especially so given kgdb's users are currently
conditioned to avoid recursive traps).

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200927211531.1380577-3-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-10-01 14:23:21 +01:00
Daniel Thompson
f2d10ff4a9 kgdb: Honour the kprobe blocklist when setting breakpoints
Currently kgdb has absolutely no safety rails in place to discourage or
prevent a user from placing a breakpoint in dangerous places such as
the debugger's own trap entry/exit and other places where it is not safe
to take synchronous traps.

Introduce a new config symbol KGDB_HONOUR_BLOCKLIST and modify the
default implementation of kgdb_validate_break_address() so that we use
the kprobe blocklist to prohibit instrumentation of critical functions
if the config symbol is set. The config symbol dependencies are set to
ensure that the blocklist will be enabled by default if we enable KGDB
and are compiling for an architecture where we HAVE_KPROBES.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20200927211531.1380577-2-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-28 12:14:08 +01:00
Youling Tang
e16c33e290 kernel/debug: Fix spelling mistake in debug_core.c
Fix typo: "notifiter" --> "notifier"
	  "overriden" --> "overridden"

Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Link: https://lore.kernel.org/r/1596793480-22559-1-git-send-email-tangyouling@loongson.cn
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-11 15:57:37 +01:00
Davidlohr Bueso
ece4ceaf2e kdb: Use newer api for tasklist scanning
This kills using the do_each_thread/while_each_thread combo to
iterate all threads and uses for_each_process_thread() instead,
maintaining semantics. while_each_thread() is ultimately racy
and deprecated;  although in this particular case there is no
concurrency so it doesn't matter. Still lets trivially get rid
of two more users.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20200907203206.21293-1-dave@stgolabs.net
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08 14:36:46 +01:00
Douglas Anderson
b18b099e04 kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"
On my system the kernel processes the "kgdb_earlycon" parameter before
the "kgdbcon" parameter.  When we setup "kgdb_earlycon" we'll end up
in kgdb_register_callbacks() and "kgdb_use_con" won't have been set
yet so we'll never get around to starting "kgdbcon".  Let's remedy
this by detecting that the IO module was already registered when
setting "kgdb_use_con" and registering the console then.

As part of this, to avoid pre-declaring things, move the handling of
the "kgdbcon" further down in the file.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200630151422.1.I4aa062751ff5e281f5116655c976dff545c09a46@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08 14:34:40 +01:00
Cengiz Can
fcdb84cc5b kdb: remove unnecessary null check of dbg_io_ops
`kdb_msg_write` operates on a global `struct kgdb_io *` called
`dbg_io_ops`.

It's initialized in `debug_core.c` and checked throughout the debug
flow.

There's a null check in `kdb_msg_write` which triggers static analyzers
and gives the (almost entirely wrong) impression that it can be null.

Coverity scanner caught this as CID 1465042.

I have removed the unnecessary null check and eliminated false-positive
forward null dereference warning.

Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
Link: https://lore.kernel.org/r/20200630082922.28672-1-cengiz@kernel.wtf
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08 14:34:40 +01:00
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Linus Torvalds
99ea1521a0 Remove uninitialized_var() macro for v5.9-rc1
- Clean up non-trivial uses of uninitialized_var()
 - Update documentation and checkpatch for uninitialized_var() removal
 - Treewide removal of uninitialized_var()
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Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
2020-08-04 13:49:43 -07:00
Kees Cook
b13fecb1c3 treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()
This converts all the existing DECLARE_TASKLET() (and ...DISABLED)
macros with DECLARE_TASKLET_OLD() in preparation for refactoring the
tasklet callback type. All existing DECLARE_TASKLET() users had a "0"
data argument, it has been removed here as well.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-30 11:15:58 -07:00
Kees Cook
3f649ab728 treewide: Remove uninitialized_var() usage
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:15 -07:00
Vincent Chen
8c080d3a97
kgdb: enable arch to support XML packet.
The XML packet could be supported by required architecture if the
architecture defines CONFIG_HAVE_ARCH_KGDB_QXFER_PKT and implement its own
kgdb_arch_handle_qxfer_pkt(). Except for the kgdb_arch_handle_qxfer_pkt(),
the architecture also needs to record the feature supported by gdb stub
into the kgdb_arch_gdb_stub_feature, and these features will be reported
to host gdb when gdb stub receives the qSupported packet.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-07-09 20:09:28 -07:00
Douglas Anderson
440ab9e10e kgdb: Avoid suspicious RCU usage warning
At times when I'm using kgdb I see a splat on my console about
suspicious RCU usage.  I managed to come up with a case that could
reproduce this that looked like this:

  WARNING: suspicious RCU usage
  5.7.0-rc4+ #609 Not tainted
  -----------------------------
  kernel/pid.c:395 find_task_by_pid_ns() needs rcu_read_lock() protection!

  other info that might help us debug this:

    rcu_scheduler_active = 2, debug_locks = 1
  3 locks held by swapper/0/1:
   #0: ffffff81b6b8e988 (&dev->mutex){....}-{3:3}, at: __device_attach+0x40/0x13c
   #1: ffffffd01109e9e8 (dbg_master_lock){....}-{2:2}, at: kgdb_cpu_enter+0x20c/0x7ac
   #2: ffffffd01109ea90 (dbg_slave_lock){....}-{2:2}, at: kgdb_cpu_enter+0x3ec/0x7ac

  stack backtrace:
  CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc4+ #609
  Hardware name: Google Cheza (rev3+) (DT)
  Call trace:
   dump_backtrace+0x0/0x1b8
   show_stack+0x1c/0x24
   dump_stack+0xd4/0x134
   lockdep_rcu_suspicious+0xf0/0x100
   find_task_by_pid_ns+0x5c/0x80
   getthread+0x8c/0xb0
   gdb_serial_stub+0x9d4/0xd04
   kgdb_cpu_enter+0x284/0x7ac
   kgdb_handle_exception+0x174/0x20c
   kgdb_brk_fn+0x24/0x30
   call_break_hook+0x6c/0x7c
   brk_handler+0x20/0x5c
   do_debug_exception+0x1c8/0x22c
   el1_sync_handler+0x3c/0xe4
   el1_sync+0x7c/0x100
   rpmh_rsc_probe+0x38/0x420
   platform_drv_probe+0x94/0xb4
   really_probe+0x134/0x300
   driver_probe_device+0x68/0x100
   __device_attach_driver+0x90/0xa8
   bus_for_each_drv+0x84/0xcc
   __device_attach+0xb4/0x13c
   device_initial_probe+0x18/0x20
   bus_probe_device+0x38/0x98
   device_add+0x38c/0x420

If I understand properly we should just be able to blanket kgdb under
one big RCU read lock and the problem should go away.  We'll add it to
the beast-of-a-function known as kgdb_cpu_enter().

With this I no longer get any splats and things seem to work fine.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200602154729.v2.1.I70e0d4fd46d5ed2aaf0c98a355e8e1b7a5bb7e4e@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-26 15:41:40 +01:00
Sumit Garg
5946d1f5b3 kdb: Switch to use safer dbg_io_ops over console APIs
In kgdb context, calling console handlers aren't safe due to locks used
in those handlers which could in turn lead to a deadlock. Although, using
oops_in_progress increases the chance to bypass locks in most console
handlers but it might not be sufficient enough in case a console uses
more locks (VT/TTY is good example).

Currently when a driver provides both polling I/O and a console then kdb
will output using the console. We can increase robustness by using the
currently active polling I/O driver (which should be lockless) instead
of the corresponding console. For several common cases (e.g. an
embedded system with a single serial port that is used both for console
output and debugger I/O) this will result in no console handler being
used.

In order to achieve this we need to reverse the order of preference to
use dbg_io_ops (uses polling I/O mode) over console APIs. So we just
store "struct console" that represents debugger I/O in dbg_io_ops and
while emitting kdb messages, skip console that matches dbg_io_ops
console in order to avoid duplicate messages. After this change,
"is_console" param becomes redundant and hence removed.

Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/1591264879-25920-5-git-send-email-sumit.garg@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-26 15:40:16 +01:00
Sumit Garg
2a78b85b70 kdb: Make kdb_printf() console handling more robust
While rounding up CPUs via NMIs, its possible that a rounded up CPU
maybe holding a console port lock leading to kgdb master CPU stuck in
a deadlock during invocation of console write operations. A similar
deadlock could also be possible while using synchronous breakpoints.

So in order to avoid such a deadlock, set oops_in_progress to encourage
the console drivers to disregard their internal spin locks: in the
current calling context the risk of deadlock is a bigger problem than
risks due to re-entering the console driver. We operate directly on
oops_in_progress rather than using bust_spinlocks() because the calls
bust_spinlocks() makes on exit are not appropriate for this calling
context.

Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-4-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-25 12:04:30 +01:00
Sumit Garg
e8857288bb kdb: Check status of console prior to invoking handlers
Check if a console is enabled prior to invoking corresponding write
handler.

Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-3-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-25 12:04:29 +01:00
Sumit Garg
9d71b344f8 kdb: Re-factor kdb_printf() message write code
Re-factor kdb_printf() message write code in order to avoid duplication
of code and thereby increase readability.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-2-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-25 12:04:29 +01:00
Christoph Hellwig
fe557319aa maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault
Better describe what these functions do.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-17 10:57:41 -07:00
Dmitry Safonov
9cb8f069de kernel: rename show_stack_loglvl() => show_stack()
Now the last users of show_stack() got converted to use an explicit log
level, show_stack_loglvl() can drop it's redundant suffix and become once
again well known show_stack().

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:13 -07:00