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136 commits

Author SHA1 Message Date
Andrea Righi
a419beac4a module/decompress: use vmalloc() for zstd decompression workspace 
Using kmalloc() to allocate the decompression workspace for zstd may
trigger the following warning when large modules are loaded (i.e., xfs):

[    2.961884] WARNING: CPU: 1 PID: 254 at mm/page_alloc.c:4453 __alloc_pages+0x2c3/0x350
...
[    2.989033] Call Trace:
[    2.989841]  <TASK>
[    2.990614]  ? show_regs+0x6d/0x80
[    2.991573]  ? __warn+0x89/0x160
[    2.992485]  ? __alloc_pages+0x2c3/0x350
[    2.993520]  ? report_bug+0x17e/0x1b0
[    2.994506]  ? handle_bug+0x51/0xa0
[    2.995474]  ? exc_invalid_op+0x18/0x80
[    2.996469]  ? asm_exc_invalid_op+0x1b/0x20
[    2.997530]  ? module_zstd_decompress+0xdc/0x2a0
[    2.998665]  ? __alloc_pages+0x2c3/0x350
[    2.999695]  ? module_zstd_decompress+0xdc/0x2a0
[    3.000821]  __kmalloc_large_node+0x7a/0x150
[    3.001920]  __kmalloc+0xdb/0x170
[    3.002824]  module_zstd_decompress+0xdc/0x2a0
[    3.003857]  module_decompress+0x37/0xc0
[    3.004688]  init_module_from_file+0xd0/0x100
[    3.005668]  idempotent_init_module+0x11c/0x2b0
[    3.006632]  __x64_sys_finit_module+0x64/0xd0
[    3.007568]  do_syscall_64+0x59/0x90
[    3.008373]  ? ksys_read+0x73/0x100
[    3.009395]  ? exit_to_user_mode_prepare+0x30/0xb0
[    3.010531]  ? syscall_exit_to_user_mode+0x37/0x60
[    3.011662]  ? do_syscall_64+0x68/0x90
[    3.012511]  ? do_syscall_64+0x68/0x90
[    3.013364]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8

However, continuous physical memory does not seem to be required in
module_zstd_decompress(), so use vmalloc() instead, to prevent the
warning and avoid potential failures at loading compressed modules.

Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-08-29 09:39:08 -07:00
James Morse
2abcc4b5a6 module: Expose module_init_layout_section() 
module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.

arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.

Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.

Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
|  module_emit_plt_entry+0x184/0x1cc
|  apply_relocate_add+0x2bc/0x8e4
|  load_module+0xe34/0x1bd4
|  init_module_from_file+0x84/0xc0
|  __arm64_sys_finit_module+0x1b8/0x27c
|  invoke_syscall.constprop.0+0x5c/0x104
|  do_el0_svc+0x58/0x160
|  el0_svc+0x38/0x110
|  el0t_64_sync_handler+0xc0/0xc4
|  el0t_64_sync+0x190/0x194

Instead of duplicating module_init_layout_section()s logic, expose it.

Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-08-03 13:42:02 -07:00
Christoph Hellwig
9011e49d54 modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules 
It has recently come to my attention that nvidia is circumventing the
protection added in 262e6ae708 ("modules: inherit
TAINT_PROPRIETARY_MODULE") by importing exports from their proprietary
modules into an allegedly GPL licensed module and then rexporting them.

Given that symbol_get was only ever intended for tightly cooperating
modules using very internal symbols it is logical to restrict it to
being used on EXPORT_SYMBOL_GPL and prevent nvidia from costly DMCA
Circumvention of Access Controls law suites.

All symbols except for four used through symbol_get were already exported
as EXPORT_SYMBOL_GPL, and the remaining four ones were switched over in
the preparation patches.

Fixes: 262e6ae708 ("modules: inherit TAINT_PROPRIETARY_MODULE")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-08-02 11:18:22 -07:00
Palmer Dabbelt
ff09f6fd29 modpost, kallsyms: Treat add '$'-prefixed symbols as mapping symbols 
Trying to restrict the '$'-prefix change to RISC-V caused some fallout,
so let's just treat all those symbols as special.

Fixes: c05780ef3c ("module: Ignore RISC-V mapping symbols too")
Link: https://lore.kernel.org/all/20230712015747.77263-1-wangkefeng.wang@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-07-24 12:09:47 -07:00
Palmer Dabbelt
c05780ef3c module: Ignore RISC-V mapping symbols too 
RISC-V has an extended form of mapping symbols that we use to encode
the ISA when it changes in the middle of an ELF.  This trips up modpost
as a build failure, I haven't yet verified it yet but I believe the
kallsyms difference should result in stacks looking sane again.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/9d9e2902-5489-4bf0-d9cb-556c8e5d71c2@infradead.org/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-07-10 12:45:23 -07:00
Linus Torvalds
f196220715 module: fix init_module_from_file() error handling 
Vegard Nossum pointed out two different problems with the error handling
in init_module_from_file():

 (a) the idempotent loading code didn't clean up properly in some error
     cases, leaving the on-stack 'struct idempotent' element still in
     the hash table

 (b) failure to read the module file would nonsensically update the
     'invalid_kread_bytes' stat counter with the error value

The first error is quite nasty, in that it can then cause subsequent
idempotent loads of that same file to access stale stack contents of the
previous failure.  The case may not happen in any normal situation
(explaining all the "Tested-by's on the original change), and requires
admin privileges, but syzkaller triggers random bad behavior as a
result:

    BUG: soft lockup in sys_finit_module
    BUG: unable to handle kernel paging request in init_module_from_file
    general protection fault in init_module_from_file
    INFO: task hung in init_module_from_file
    KASAN: out-of-bounds Read in init_module_from_file
    KASAN: slab-out-of-bounds Read in init_module_from_file
    ...

The second error is fairly benign and just leads to nonsensical stats
(and has been around since the debug stats were added).

Vegard also provided a patch for the idempotent loading issue, but I'd
rather re-organize the code and make it more legible using another level
of helper functions than add the usual "goto out" error handling.

Link: https://lore.kernel.org/lkml/20230704100852.23452-1-vegard.nossum@oracle.com/
Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reported-by: syzbot+9c2bdc9d24e4a7abe741@syzkaller.appspotmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2023-07-04 10:17:11 -07:00
Linus Torvalds
ad2885979e Kbuild updates for v6.5 
- Remove the deprecated rule to build *.dtbo from *.dts
 
  - Refactor section mismatch detection in modpost
 
  - Fix bogus ARM section mismatch detections
 
  - Fix error of 'make gtags' with O= option
 
  - Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error with
    the latest LLVM version
 
  - Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed
 
  - Ignore more compiler-generated symbols for kallsyms
 
  - Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles
 
  - Enable more kernel-doc warnings with W=2
 
  - Refactor <linux/export.h> by generating KSYMTAB data by modpost
 
  - Deprecate <asm/export.h> and <asm-generic/export.h>
 
  - Remove the EXPORT_DATA_SYMBOL macro
 
  - Move the check for static EXPORT_SYMBOL back to modpost, which makes
    the build faster
 
  - Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm
 
  - Warn missing MODULE_DESCRIPTION when building modules with W=1
 
  - Make 'make clean' robust against too long argument error
 
  - Exclude more objects from GCOV to fix CFI failures with GCOV
 
  - Allow 'make modules_install' to install modules.builtin and
    modules.builtin.modinfo even when CONFIG_MODULES is disabled
 
  - Include modules.builtin and modules.builtin.modinfo in the linux-image
    Debian package even when CONFIG_MODULES is disabled
 
  - Revive "Entering directory" logging for the latest Make version
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Merge tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Remove the deprecated rule to build *.dtbo from *.dts

 - Refactor section mismatch detection in modpost

 - Fix bogus ARM section mismatch detections

 - Fix error of 'make gtags' with O= option

 - Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error
   with the latest LLVM version

 - Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed

 - Ignore more compiler-generated symbols for kallsyms

 - Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles

 - Enable more kernel-doc warnings with W=2

 - Refactor <linux/export.h> by generating KSYMTAB data by modpost

 - Deprecate <asm/export.h> and <asm-generic/export.h>

 - Remove the EXPORT_DATA_SYMBOL macro

 - Move the check for static EXPORT_SYMBOL back to modpost, which makes
   the build faster

 - Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm

 - Warn missing MODULE_DESCRIPTION when building modules with W=1

 - Make 'make clean' robust against too long argument error

 - Exclude more objects from GCOV to fix CFI failures with GCOV

 - Allow 'make modules_install' to install modules.builtin and
   modules.builtin.modinfo even when CONFIG_MODULES is disabled

 - Include modules.builtin and modules.builtin.modinfo in the
   linux-image Debian package even when CONFIG_MODULES is disabled

 - Revive "Entering directory" logging for the latest Make version

* tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits)
  modpost: define more R_ARM_* for old distributions
  kbuild: revive "Entering directory" for Make >= 4.4.1
  kbuild: set correct abs_srctree and abs_objtree for package builds
  scripts/mksysmap: Ignore prefixed KCFI symbols
  kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb
  kbuild: builddeb: always make modules_install, to install modules.builtin*
  modpost: continue even with unknown relocation type
  modpost: factor out Elf_Sym pointer calculation to section_rel()
  modpost: factor out inst location calculation to section_rel()
  kbuild: Disable GCOV for *.mod.o
  kbuild: Fix CFI failures with GCOV
  kbuild: make clean rule robust against too long argument error
  script: modpost: emit a warning when the description is missing
  kbuild: make modules_install copy modules.builtin(.modinfo)
  linux/export.h: rename 'sec' argument to 'license'
  modpost: show offset from symbol for section mismatch warnings
  modpost: merge two similar section mismatch warnings
  kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
  modpost: use null string instead of NULL pointer for default namespace
  modpost: squash sym_update_namespace() into sym_add_exported()
  ...
 2023-07-01 09:24:31 -07:00
Linus Torvalds
4e3c09e954 v6.5-rc1-modules-next 
The changes queued up for v6.5-rc1 for modules are pretty tame, mostly
 code removal of moving of code. Only two minor functional changes are
 made, the only one which stands out is Sebastian Andrzej Siewior's
 simplification of module reference counting by removing preempt_disable()
 and that has been tested on linux-next for well over a month without
 no regressions. I'm now, I guess, also a kitchen sink for some kallsyms
 changes.
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Merge tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull module updates from Luis Chamberlain:
 "The changes queued up for modules are pretty tame, mostly code removal
  of moving of code.

  Only two minor functional changes are made, the only one which stands
  out is Sebastian Andrzej Siewior's simplification of module reference
  counting by removing preempt_disable() and that has been tested on
  linux-next for well over a month without no regressions.

  I'm now, I guess, also a kitchen sink for some kallsyms changes"

[ There was a mis-communication about the concurrent module load changes
  that I had expected to come through Luis despite me authoring the
  patch. So some of the module updates were left hanging in the email
  ether, and I just committed them separately.

  It's my bad - I should have made it more clear that I expected my
  own patches to come through the module tree too. Now they missed
  linux-next, but hopefully that won't cause any issues    - Linus ]

* tag 'v6.5-rc1-modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  kallsyms: make kallsyms_show_value() as generic function
  kallsyms: move kallsyms_show_value() out of kallsyms.c
  kallsyms: remove unsed API lookup_symbol_attrs
  kallsyms: remove unused arch_get_kallsym() helper
  module: Remove preempt_disable() from module reference counting.
 2023-06-28 15:51:08 -07:00
Linus Torvalds
9b9879fc03 modules: catch concurrent module loads, treat them as idempotent 
This is the new-and-improved attempt at avoiding huge memory load spikes
when the user space boot sequence tries to load hundreds (or even
thousands) of redundant duplicate modules in parallel.

See commit 9828ed3f69 ("module: error out early on concurrent load of
the same module file") for background and an earlier failed attempt that
was reverted.

That earlier attempt just said "concurrently loading the same module is
silly, just open the module file exclusively and return -ETXTBSY if
somebody else is already loading it".

While it is true that concurrent module loads of the same module is
silly, the reason that earlier attempt then failed was that the
concurrently loaded module would often be a prerequisite for another
module.

Thus failing to load the prerequisite would then cause cascading
failures of the other modules, rather than just short-circuiting that
one unnecessary module load.

At the same time, we still really don't want to load the contents of the
same module file hundreds of times, only to then wait for an eventually
successful load, and have everybody else return -EEXIST.

As a result, this takes another approach, and treats concurrent module
loads from the same file as "idempotent" in the inode.  So if one module
load is ongoing, we don't start a new one, but instead just wait for the
first one to complete and return the same return value as it did.

So unlike the first attempt, this does not return early: the intent is
not to speed up the boot, but to avoid a thundering herd problem in
allocating memory (both physical and virtual) for a module more than
once.

Also note that this does change behavior: it used to be that when you
had concurrent loads, you'd have one "winner" that would return success,
and everybody else would return -EEXIST.

In contrast, this idempotent logic goes all Oprah on the problem, and
says "You are a winner! And you are a winner! We are ALL winners".  But
since there's no possible actual real semantic difference between "you
loaded the module" and "somebody else already loaded the module", this
is more of a feel-good change than an actual honest-to-goodness semantic
change.

Of course, any true Johnny-come-latelies that don't get caught in the
concurrency filter will still return -EEXIST.  It's no different from
not even getting a seat at an Oprah taping.  That's life.

See the long thread on the kernel mailing list about this all, which
includes some numbers for memory use before and after the patch.

Link: https://lore.kernel.org/lkml/20230524213620.3509138-1-mcgrof@kernel.org/
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Tested-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Rudi Heitbaum <rudi@heitbaum..com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2023-06-28 15:46:44 -07:00
Linus Torvalds
054a73009c module: split up 'finit_module()' into init_module_from_file() helper 
This will simplify the next step, where we can then key off the inode to
do one idempotent module load.

Let's do the obvious re-organization in one step, and then the new code
in another.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2023-06-28 15:46:43 -07:00
Masahiro Yamada
ddb5cdbafa kbuild: generate KSYMTAB entries by modpost 
Commit 7b4537199a ("kbuild: link symbol CRCs at final link, removing
CONFIG_MODULE_REL_CRCS") made modpost output CRCs in the same way
whether the EXPORT_SYMBOL() is placed in *.c or *.S.

For further cleanups, this commit applies a similar approach to the
entire data structure of EXPORT_SYMBOL().

The EXPORT_SYMBOL() compilation is split into two stages.

When a source file is compiled, EXPORT_SYMBOL() will be converted into
a dummy symbol in the .export_symbol section.

For example,

    EXPORT_SYMBOL(foo);
    EXPORT_SYMBOL_NS_GPL(bar, BAR_NAMESPACE);

will be encoded into the following assembly code:

    .section ".export_symbol","a"
    __export_symbol_foo:
            .asciz ""                      /* license */
            .asciz ""                      /* name space */
            .balign 8
            .quad foo                      /* symbol reference */
    .previous

    .section ".export_symbol","a"
    __export_symbol_bar:
            .asciz "GPL"                   /* license */
            .asciz "BAR_NAMESPACE"         /* name space */
            .balign 8
            .quad bar                      /* symbol reference */
    .previous

They are mere markers to tell modpost the name, license, and namespace
of the symbols. They will be dropped from the final vmlinux and modules
because the *(.export_symbol) will go into /DISCARD/ in the linker script.

Then, modpost extracts all the information about EXPORT_SYMBOL() from the
.export_symbol section, and generates the final C code:

    KSYMTAB_FUNC(foo, "", "");
    KSYMTAB_FUNC(bar, "_gpl", "BAR_NAMESPACE");

KSYMTAB_FUNC() (or KSYMTAB_DATA() if it is data) is expanded to struct
kernel_symbol that will be linked to the vmlinux or a module.

With this change, EXPORT_SYMBOL() works in the same way for *.c and *.S
files, providing the following benefits.

[1] Deprecate EXPORT_DATA_SYMBOL()

In the old days, EXPORT_SYMBOL() was only available in C files. To export
a symbol in *.S, EXPORT_SYMBOL() was placed in a separate *.c file.
arch/arm/kernel/armksyms.c is one example written in the classic manner.

Commit 22823ab419 ("EXPORT_SYMBOL() for asm") removed this limitation.
Since then, EXPORT_SYMBOL() can be placed close to the symbol definition
in *.S files. It was a nice improvement.

However, as that commit mentioned, you need to use EXPORT_DATA_SYMBOL()
for data objects on some architectures.

In the new approach, modpost checks symbol's type (STT_FUNC or not),
and outputs KSYMTAB_FUNC() or KSYMTAB_DATA() accordingly.

There are only two users of EXPORT_DATA_SYMBOL:

  EXPORT_DATA_SYMBOL_GPL(empty_zero_page)    (arch/ia64/kernel/head.S)
  EXPORT_DATA_SYMBOL(ia64_ivt)               (arch/ia64/kernel/ivt.S)

They are transformed as follows and output into .vmlinux.export.c

  KSYMTAB_DATA(empty_zero_page, "_gpl", "");
  KSYMTAB_DATA(ia64_ivt, "", "");

The other EXPORT_SYMBOL users in ia64 assembly are output as
KSYMTAB_FUNC().

EXPORT_DATA_SYMBOL() is now deprecated.

[2] merge <linux/export.h> and <asm-generic/export.h>

There are two similar header implementations:

  include/linux/export.h        for .c files
  include/asm-generic/export.h  for .S files

Ideally, the functionality should be consistent between them, but they
tend to diverge.

Commit 8651ec01da ("module: add support for symbol namespaces.") did
not support the namespace for *.S files.

This commit shifts the essential implementation part to C, which supports
EXPORT_SYMBOL_NS() for *.S files.

<asm/export.h> and <asm-generic/export.h> will remain as a wrapper of
<linux/export.h> for a while.

They will be removed after #include <asm/export.h> directives are all
replaced with #include <linux/export.h>.

[3] Implement CONFIG_TRIM_UNUSED_KSYMS in one-pass algorithm (by a later commit)

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.

We can do this better now; modpost can selectively emit KSYMTAB entries
that are really used by modules.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
 2023-06-22 21:17:10 +09:00
Lucas De Marchi
fadb74f9f2 module/decompress: Fix error checking on zstd decompression 
While implementing support for in-kernel decompression in kmod,
finit_module() was returning a very suspicious value:

	finit_module(3, "", MODULE_INIT_COMPRESSED_FILE) = 18446744072717407296

It turns out the check for module_get_next_page() failing is wrong,
and hence the decompression was not really taking place. Invert
the condition to fix it.

Fixes: 169a58ad82 ("module/decompress: Support zstd in-kernel decompression")
Cc: stable@kernel.org
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-06-01 14:36:46 -07:00
Song Liu
db3e33dd8b module: fix module load for ia64 
Frank reported boot regression in ia64 as:

ELILO v3.16 for EFI/IA-64
..
Uncompressing Linux... done
Loading file AC100221.initrd.img...done
[    0.000000] Linux version 6.4.0-rc3 (root@x4270) (ia64-linux-gcc
(GCC) 12.2.0, GNU ld (GNU Binutils) 2.39) #1 SMP Thu May 25 15:52:20
CEST 2023
[    0.000000] efi: EFI v1.1 by HP
[    0.000000] efi: SALsystab=0x3ee7a000 ACPI 2.0=0x3fe2a000
ESI=0x3ee7b000 SMBIOS=0x3ee7c000 HCDP=0x3fe28000
[    0.000000] PCDP: v3 at 0x3fe28000
[    0.000000] earlycon: uart8250 at MMIO 0x00000000f4050000 (options
'9600n8')
[    0.000000] printk: bootconsole [uart8250] enabled
[    0.000000] ACPI: Early table checksum verification disabled
[    0.000000] ACPI: RSDP 0x000000003FE2A000 000028 (v02 HP    )
[    0.000000] ACPI: XSDT 0x000000003FE2A02C 0000CC (v01 HP     rx2620
00000000 HP   00000000)
[...]
[    3.793350] Run /init as init process
Loading, please wait...
Starting systemd-udevd version 252.6-1
[    3.951100] ------------[ cut here ]------------
[    3.951100] WARNING: CPU: 6 PID: 140 at kernel/module/main.c:1547
__layout_sections+0x370/0x3c0
[    3.949512] Unable to handle kernel paging request at virtual address
1000000000000000
[    3.951100] Modules linked in:
[    3.951100] CPU: 6 PID: 140 Comm: (udev-worker) Not tainted 6.4.0-rc3 #1
[    3.956161] (udev-worker)[142]: Oops 11003706212352 [1]
[    3.951774] Hardware name: hp server rx2620                   , BIOS
04.29
11/30/2007
[    3.951774]
[    3.951774] Call Trace:
[    3.958339] Unable to handle kernel paging request at virtual address
1000000000000000
[    3.956161] Modules linked in:
[    3.951774]  [<a0000001000156d0>] show_stack.part.0+0x30/0x60
[    3.951774]                                 sp=e000000183a67b20
bsp=e000000183a61628
[    3.956161]
[    3.956161]

which bisect to module_memory change [1].

Debug showed that ia64 uses some special sections:

__layout_sections: section .got (sh_flags 10000002) matched to MOD_INVALID
__layout_sections: section .sdata (sh_flags 10000003) matched to MOD_INVALID
__layout_sections: section .sbss (sh_flags 10000003) matched to MOD_INVALID

All these sections are loaded to module core memory before [1].

Fix ia64 boot by loading these sections to MOD_DATA (core rw data).

[1] commit ac3b432839 ("module: replace module_layout with module_memory")

Fixes: ac3b432839 ("module: replace module_layout with module_memory")
Reported-by: Frank Scheiner <frank.scheiner@web.de>
Closes: https://lists.debian.org/debian-ia64/2023/05/msg00010.html
Closes: https://marc.info/?l=linux-ia64&m=168509859125505
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Song Liu <song@kernel.org>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-05-30 09:29:40 -07:00
Maninder Singh
4f521bab5b kallsyms: remove unsed API lookup_symbol_attrs 
with commit '7878c231dae0 ("slab: remove /proc/slab_allocators")'
lookup_symbol_attrs usage is removed.

Thus removing redundant API.

Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-05-26 15:10:18 -07:00
Sebastian Andrzej Siewior
cb0b50b813 module: Remove preempt_disable() from module reference counting. 
The preempt_disable() section in module_put() was added in commit
   e1783a240f ("module: Use this_cpu_xx to dynamically allocate counters")

while the per-CPU counter were switched to another API. The API requires
that during the RMW operation the CPU remained the same.

This counting API was later replaced with atomic_t in commit
   2f35c41f58 ("module: Replace module_ref with atomic_t refcnt")

Since this atomic_t replacement there is no need to keep preemption
disabled while the reference counter is modified.

Remove preempt_disable() from module_put(), __module_get() and
try_module_get().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-05-23 22:23:18 -07:00
Harshit Mogalapalli
d36f6efbe0 module: Fix use-after-free bug in read_file_mod_stats() 
Smatch warns:
	kernel/module/stats.c:394 read_file_mod_stats()
	warn: passing freed memory 'buf'

We are passing 'buf' to simple_read_from_buffer() after freeing it.

Fix this by changing the order of 'simple_read_from_buffer' and 'kfree'.

Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-05-22 14:13:13 -07:00
Arnd Bergmann
0b891c83d8 module: include internal.h in module/dups.c 
Two newly introduced functions are declared in a header that is not
included before the definition, causing a warning with sparse or
'make W=1':

kernel/module/dups.c:118:6: error: no previous prototype for 'kmod_dup_request_exists_wait' [-Werror=missing-prototypes]
  118 | bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/module/dups.c:220:6: error: no previous prototype for 'kmod_dup_request_announce' [-Werror=missing-prototypes]
  220 | void kmod_dup_request_announce(char *module_name, int ret)
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~

Add an explicit include to ensure the prototypes match.

Fixes: 8660484ed1 ("module: add debugging auto-load duplicate module support")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304141440.DYO4NAzp-lkp@intel.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-05-02 20:33:36 -07:00
Linus Torvalds
b6a7828502 modules-6.4-rc1 
The summary of the changes for this pull requests is:
 
  * Song Liu's new struct module_memory replacement
  * Nick Alcock's MODULE_LICENSE() removal for non-modules
  * My cleanups and enhancements to reduce the areas where we vmalloc
    module memory for duplicates, and the respective debug code which
    proves the remaining vmalloc pressure comes from userspace.
 
 Most of the changes have been in linux-next for quite some time except
 the minor fixes I made to check if a module was already loaded
 prior to allocating the final module memory with vmalloc and the
 respective debug code it introduces to help clarify the issue. Although
 the functional change is small it is rather safe as it can only *help*
 reduce vmalloc space for duplicates and is confirmed to fix a bootup
 issue with over 400 CPUs with KASAN enabled. I don't expect stable
 kernels to pick up that fix as the cleanups would have also had to have
 been picked up. Folks on larger CPU systems with modules will want to
 just upgrade if vmalloc space has been an issue on bootup.
 
 Given the size of this request, here's some more elaborate details
 on this pull request.
 
 The functional change change in this pull request is the very first
 patch from Song Liu which replaces the struct module_layout with a new
 struct module memory. The old data structure tried to put together all
 types of supported module memory types in one data structure, the new
 one abstracts the differences in memory types in a module to allow each
 one to provide their own set of details. This paves the way in the
 future so we can deal with them in a cleaner way. If you look at changes
 they also provide a nice cleanup of how we handle these different memory
 areas in a module. This change has been in linux-next since before the
 merge window opened for v6.3 so to provide more than a full kernel cycle
 of testing. It's a good thing as quite a bit of fixes have been found
 for it.
 
 Jason Baron then made dynamic debug a first class citizen module user by
 using module notifier callbacks to allocate / remove module specific
 dynamic debug information.
 
 Nick Alcock has done quite a bit of work cross-tree to remove module
 license tags from things which cannot possibly be module at my request
 so to:
 
   a) help him with his longer term tooling goals which require a
      deterministic evaluation if a piece a symbol code could ever be
      part of a module or not. But quite recently it is has been made
      clear that tooling is not the only one that would benefit.
      Disambiguating symbols also helps efforts such as live patching,
      kprobes and BPF, but for other reasons and R&D on this area
      is active with no clear solution in sight.
 
   b) help us inch closer to the now generally accepted long term goal
      of automating all the MODULE_LICENSE() tags from SPDX license tags
 
 In so far as a) is concerned, although module license tags are a no-op
 for non-modules, tools which would want create a mapping of possible
 modules can only rely on the module license tag after the commit
 8b41fc4454 ("kbuild: create modules.builtin without Makefile.modbuiltin
 or tristate.conf").  Nick has been working on this *for years* and
 AFAICT I was the only one to suggest two alternatives to this approach
 for tooling. The complexity in one of my suggested approaches lies in
 that we'd need a possible-obj-m and a could-be-module which would check
 if the object being built is part of any kconfig build which could ever
 lead to it being part of a module, and if so define a new define
 -DPOSSIBLE_MODULE [0]. A more obvious yet theoretical approach I've
 suggested would be to have a tristate in kconfig imply the same new
 -DPOSSIBLE_MODULE as well but that means getting kconfig symbol names
 mapping to modules always, and I don't think that's the case today. I am
 not aware of Nick or anyone exploring either of these options. Quite
 recently Josh Poimboeuf has pointed out that live patching, kprobes and
 BPF would benefit from resolving some part of the disambiguation as
 well but for other reasons. The function granularity KASLR (fgkaslr)
 patches were mentioned but Joe Lawrence has clarified this effort has
 been dropped with no clear solution in sight [1].
 
 In the meantime removing module license tags from code which could never
 be modules is welcomed for both objectives mentioned above. Some
 developers have also welcomed these changes as it has helped clarify
 when a module was never possible and they forgot to clean this up,
 and so you'll see quite a bit of Nick's patches in other pull
 requests for this merge window. I just picked up the stragglers after
 rc3. LWN has good coverage on the motivation behind this work [2] and
 the typical cross-tree issues he ran into along the way. The only
 concrete blocker issue he ran into was that we should not remove the
 MODULE_LICENSE() tags from files which have no SPDX tags yet, even if
 they can never be modules. Nick ended up giving up on his efforts due
 to having to do this vetting and backlash he ran into from folks who
 really did *not understand* the core of the issue nor were providing
 any alternative / guidance. I've gone through his changes and dropped
 the patches which dropped the module license tags where an SPDX
 license tag was missing, it only consisted of 11 drivers.  To see
 if a pull request deals with a file which lacks SPDX tags you
 can just use:
 
   ./scripts/spdxcheck.py -f \
 	$(git diff --name-only commid-id | xargs echo)
 
 You'll see a core module file in this pull request for the above,
 but that's not related to his changes. WE just need to add the SPDX
 license tag for the kernel/module/kmod.c file in the future but
 it demonstrates the effectiveness of the script.
 
 Most of Nick's changes were spread out through different trees,
 and I just picked up the slack after rc3 for the last kernel was out.
 Those changes have been in linux-next for over two weeks.
 
 The cleanups, debug code I added and final fix I added for modules
 were motivated by David Hildenbrand's report of boot failing on
 a systems with over 400 CPUs when KASAN was enabled due to running
 out of virtual memory space. Although the functional change only
 consists of 3 lines in the patch "module: avoid allocation if module is
 already present and ready", proving that this was the best we can
 do on the modules side took quite a bit of effort and new debug code.
 
 The initial cleanups I did on the modules side of things has been
 in linux-next since around rc3 of the last kernel, the actual final
 fix for and debug code however have only been in linux-next for about a
 week or so but I think it is worth getting that code in for this merge
 window as it does help fix / prove / evaluate the issues reported
 with larger number of CPUs. Userspace is not yet fixed as it is taking
 a bit of time for folks to understand the crux of the issue and find a
 proper resolution. Worst come to worst, I have a kludge-of-concept [3]
 of how to make kernel_read*() calls for modules unique / converge them,
 but I'm currently inclined to just see if userspace can fix this
 instead.
 
 [0] https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/
 [1] https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com
 [2] https://lwn.net/Articles/927569/
 [3] https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org
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Merge tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull module updates from Luis Chamberlain:
 "The summary of the changes for this pull requests is:

   - Song Liu's new struct module_memory replacement

   - Nick Alcock's MODULE_LICENSE() removal for non-modules

   - My cleanups and enhancements to reduce the areas where we vmalloc
     module memory for duplicates, and the respective debug code which
     proves the remaining vmalloc pressure comes from userspace.

  Most of the changes have been in linux-next for quite some time except
  the minor fixes I made to check if a module was already loaded prior
  to allocating the final module memory with vmalloc and the respective
  debug code it introduces to help clarify the issue. Although the
  functional change is small it is rather safe as it can only *help*
  reduce vmalloc space for duplicates and is confirmed to fix a bootup
  issue with over 400 CPUs with KASAN enabled. I don't expect stable
  kernels to pick up that fix as the cleanups would have also had to
  have been picked up. Folks on larger CPU systems with modules will
  want to just upgrade if vmalloc space has been an issue on bootup.

  Given the size of this request, here's some more elaborate details:

  The functional change change in this pull request is the very first
  patch from Song Liu which replaces the 'struct module_layout' with a
  new 'struct module_memory'. The old data structure tried to put
  together all types of supported module memory types in one data
  structure, the new one abstracts the differences in memory types in a
  module to allow each one to provide their own set of details. This
  paves the way in the future so we can deal with them in a cleaner way.
  If you look at changes they also provide a nice cleanup of how we
  handle these different memory areas in a module. This change has been
  in linux-next since before the merge window opened for v6.3 so to
  provide more than a full kernel cycle of testing. It's a good thing as
  quite a bit of fixes have been found for it.

  Jason Baron then made dynamic debug a first class citizen module user
  by using module notifier callbacks to allocate / remove module
  specific dynamic debug information.

  Nick Alcock has done quite a bit of work cross-tree to remove module
  license tags from things which cannot possibly be module at my request
  so to:

   a) help him with his longer term tooling goals which require a
      deterministic evaluation if a piece a symbol code could ever be
      part of a module or not. But quite recently it is has been made
      clear that tooling is not the only one that would benefit.
      Disambiguating symbols also helps efforts such as live patching,
      kprobes and BPF, but for other reasons and R&D on this area is
      active with no clear solution in sight.

   b) help us inch closer to the now generally accepted long term goal
      of automating all the MODULE_LICENSE() tags from SPDX license tags

  In so far as a) is concerned, although module license tags are a no-op
  for non-modules, tools which would want create a mapping of possible
  modules can only rely on the module license tag after the commit
  8b41fc4454 ("kbuild: create modules.builtin without
  Makefile.modbuiltin or tristate.conf").

  Nick has been working on this *for years* and AFAICT I was the only
  one to suggest two alternatives to this approach for tooling. The
  complexity in one of my suggested approaches lies in that we'd need a
  possible-obj-m and a could-be-module which would check if the object
  being built is part of any kconfig build which could ever lead to it
  being part of a module, and if so define a new define
  -DPOSSIBLE_MODULE [0].

  A more obvious yet theoretical approach I've suggested would be to
  have a tristate in kconfig imply the same new -DPOSSIBLE_MODULE as
  well but that means getting kconfig symbol names mapping to modules
  always, and I don't think that's the case today. I am not aware of
  Nick or anyone exploring either of these options. Quite recently Josh
  Poimboeuf has pointed out that live patching, kprobes and BPF would
  benefit from resolving some part of the disambiguation as well but for
  other reasons. The function granularity KASLR (fgkaslr) patches were
  mentioned but Joe Lawrence has clarified this effort has been dropped
  with no clear solution in sight [1].

  In the meantime removing module license tags from code which could
  never be modules is welcomed for both objectives mentioned above. Some
  developers have also welcomed these changes as it has helped clarify
  when a module was never possible and they forgot to clean this up, and
  so you'll see quite a bit of Nick's patches in other pull requests for
  this merge window. I just picked up the stragglers after rc3. LWN has
  good coverage on the motivation behind this work [2] and the typical
  cross-tree issues he ran into along the way. The only concrete blocker
  issue he ran into was that we should not remove the MODULE_LICENSE()
  tags from files which have no SPDX tags yet, even if they can never be
  modules. Nick ended up giving up on his efforts due to having to do
  this vetting and backlash he ran into from folks who really did *not
  understand* the core of the issue nor were providing any alternative /
  guidance. I've gone through his changes and dropped the patches which
  dropped the module license tags where an SPDX license tag was missing,
  it only consisted of 11 drivers. To see if a pull request deals with a
  file which lacks SPDX tags you can just use:

    ./scripts/spdxcheck.py -f \
	$(git diff --name-only commid-id | xargs echo)

  You'll see a core module file in this pull request for the above, but
  that's not related to his changes. WE just need to add the SPDX
  license tag for the kernel/module/kmod.c file in the future but it
  demonstrates the effectiveness of the script.

  Most of Nick's changes were spread out through different trees, and I
  just picked up the slack after rc3 for the last kernel was out. Those
  changes have been in linux-next for over two weeks.

  The cleanups, debug code I added and final fix I added for modules
  were motivated by David Hildenbrand's report of boot failing on a
  systems with over 400 CPUs when KASAN was enabled due to running out
  of virtual memory space. Although the functional change only consists
  of 3 lines in the patch "module: avoid allocation if module is already
  present and ready", proving that this was the best we can do on the
  modules side took quite a bit of effort and new debug code.

  The initial cleanups I did on the modules side of things has been in
  linux-next since around rc3 of the last kernel, the actual final fix
  for and debug code however have only been in linux-next for about a
  week or so but I think it is worth getting that code in for this merge
  window as it does help fix / prove / evaluate the issues reported with
  larger number of CPUs. Userspace is not yet fixed as it is taking a
  bit of time for folks to understand the crux of the issue and find a
  proper resolution. Worst come to worst, I have a kludge-of-concept [3]
  of how to make kernel_read*() calls for modules unique / converge
  them, but I'm currently inclined to just see if userspace can fix this
  instead"

Link: https://lore.kernel.org/all/Y/kXDqW+7d71C4wz@bombadil.infradead.org/ [0]
Link: https://lkml.kernel.org/r/025f2151-ce7c-5630-9b90-98742c97ac65@redhat.com [1]
Link: https://lwn.net/Articles/927569/ [2]
Link: https://lkml.kernel.org/r/20230414052840.1994456-3-mcgrof@kernel.org [3]

* tag 'modules-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (121 commits)
  module: add debugging auto-load duplicate module support
  module: stats: fix invalid_mod_bytes typo
  module: remove use of uninitialized variable len
  module: fix building stats for 32-bit targets
  module: stats: include uapi/linux/module.h
  module: avoid allocation if module is already present and ready
  module: add debug stats to help identify memory pressure
  module: extract patient module check into helper
  modules/kmod: replace implementation with a semaphore
  Change DEFINE_SEMAPHORE() to take a number argument
  module: fix kmemleak annotations for non init ELF sections
  module: Ignore L0 and rename is_arm_mapping_symbol()
  module: Move is_arm_mapping_symbol() to module_symbol.h
  module: Sync code of is_arm_mapping_symbol()
  scripts/gdb: use mem instead of core_layout to get the module address
  interconnect: remove module-related code
  interconnect: remove MODULE_LICENSE in non-modules
  zswap: remove MODULE_LICENSE in non-modules
  zpool: remove MODULE_LICENSE in non-modules
  x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules
  ...
 2023-04-27 16:36:55 -07:00
Linus Torvalds
6e98b09da9 Networking changes for 6.4. 
Core
 ----
 
  - Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
    default value allows for better BIG TCP performances.
 
  - Reduce compound page head access for zero-copy data transfers.
 
  - RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when possible.
 
  - Threaded NAPI improvements, adding defer skb free support and unneeded
    softirq avoidance.
 
  - Address dst_entry reference count scalability issues, via false
    sharing avoidance and optimize refcount tracking.
 
  - Add lockless accesses annotation to sk_err[_soft].
 
  - Optimize again the skb struct layout.
 
  - Extends the skb drop reasons to make it usable by multiple
    subsystems.
 
  - Better const qualifier awareness for socket casts.
 
 BPF
 ---
 
  - Add skb and XDP typed dynptrs which allow BPF programs for more
    ergonomic and less brittle iteration through data and variable-sized
    accesses.
 
  - Add a new BPF netfilter program type and minimal support to hook
    BPF programs to netfilter hooks such as prerouting or forward.
 
  - Add more precise memory usage reporting for all BPF map types.
 
  - Adds support for using {FOU,GUE} encap with an ipip device operating
    in collect_md mode and add a set of BPF kfuncs for controlling encap
    params.
 
  - Allow BPF programs to detect at load time whether a particular kfunc
    exists or not, and also add support for this in light skeleton.
 
  - Bigger batch of BPF verifier improvements to prepare for upcoming BPF
    open-coded iterators allowing for less restrictive looping capabilities.
 
  - Rework RCU enforcement in the verifier, add kptr_rcu and enforce BPF
    programs to NULL-check before passing such pointers into kfunc.
 
  - Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and in
    local storage maps.
 
  - Enable RCU semantics for task BPF kptrs and allow referenced kptr
    tasks to be stored in BPF maps.
 
  - Add support for refcounted local kptrs to the verifier for allowing
    shared ownership, useful for adding a node to both the BPF list and
    rbtree.
 
  - Add BPF verifier support for ST instructions in convert_ctx_access()
    which will help new -mcpu=v4 clang flag to start emitting them.
 
  - Add ARM32 USDT support to libbpf.
 
  - Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations.
 
 Protocols
 ---------
 
  - IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
    indicates the provenance of the IP address.
 
  - IPv6: optimize route lookup, dropping unneeded R/W lock acquisition.
 
  - Add the handshake upcall mechanism, allowing the user-space
    to implement generic TLS handshake on kernel's behalf.
 
  - Bridge: support per-{Port, VLAN} neighbor suppression, increasing
    resilience to nodes failures.
 
  - SCTP: add support for Fair Capacity and Weighted Fair Queueing
    schedulers.
 
  - MPTCP: delay first subflow allocation up to its first usage. This
    will allow for later better LSM interaction.
 
  - xfrm: Remove inner/outer modes from input/output path. These are
    not needed anymore.
 
  - WiFi:
    - reduced neighbor report (RNR) handling for AP mode
    - HW timestamping support
    - support for randomized auth/deauth TA for PASN privacy
    - per-link debugfs for multi-link
    - TC offload support for mac80211 drivers
    - mac80211 mesh fast-xmit and fast-rx support
    - enable Wi-Fi 7 (EHT) mesh support
 
 Netfilter
 ---------
 
  - Add nf_tables 'brouting' support, to force a packet to be routed
    instead of being bridged.
 
  - Update bridge netfilter and ovs conntrack helpers to handle
    IPv6 Jumbo packets properly, i.e. fetch the packet length
    from hop-by-hop extension header. This is needed for BIT TCP
    support.
 
  - The iptables 32bit compat interface isn't compiled in by default
    anymore.
 
  - Move ip(6)tables builtin icmp matches to the udptcp one.
    This has the advantage that icmp/icmpv6 match doesn't load the
    iptables/ip6tables modules anymore when iptables-nft is used.
 
  - Extended netlink error report for netdevice in flowtables and
    netdev/chains. Allow for incrementally add/delete devices to netdev
    basechain. Allow to create netdev chain without device.
 
 Driver API
 ----------
 
  - Remove redundant Device Control Error Reporting Enable, as PCI core
    has already error reporting enabled at enumeration time.
 
  - Move Multicast DB netlink handlers to core, allowing devices other
    then bridge to use them.
 
  - Allow the page_pool to directly recycle the pages from safely
    localized NAPI.
 
  - Implement lockless TX queue stop/wake combo macros, allowing for
    further code de-duplication and sanitization.
 
  - Add YNL support for user headers and struct attrs.
 
  - Add partial YNL specification for devlink.
 
  - Add partial YNL specification for ethtool.
 
  - Add tc-mqprio and tc-taprio support for preemptible traffic classes.
 
  - Add tx push buf len param to ethtool, specifies the maximum number
    of bytes of a transmitted packet a driver can push directly to the
    underlying device.
 
  - Add basic LED support for switch/phy.
 
  - Add NAPI documentation, stop relaying on external links.
 
  - Convert dsa_master_ioctl() to netdev notifier. This is a preparatory
    work to make the hardware timestamping layer selectable by user
    space.
 
  - Add transceiver support and improve the error messages for CAN-FD
    controllers.
 
 New hardware / drivers
 ----------------------
 
  - Ethernet:
    - AMD/Pensando core device support
    - MediaTek MT7981 SoC
    - MediaTek MT7988 SoC
    - Broadcom BCM53134 embedded switch
    - Texas Instruments CPSW9G ethernet switch
    - Qualcomm EMAC3 DWMAC ethernet
    - StarFive JH7110 SoC
    - NXP CBTX ethernet PHY
 
  - WiFi:
    - Apple M1 Pro/Max devices
    - RealTek rtl8710bu/rtl8188gu
    - RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset
 
  - Bluetooth:
    - Realtek RTL8821CS, RTL8851B, RTL8852BS
    - Mediatek MT7663, MT7922
    - NXP w8997
    - Actions Semi ATS2851
    - QTI WCN6855
    - Marvell 88W8997
 
  - Can:
    - STMicroelectronics bxcan stm32f429
 
 Drivers
 -------
  - Ethernet NICs:
    - Intel (1G, icg):
      - add tracking and reporting of QBV config errors.
      - add support for configuring max SDU for each Tx queue.
    - Intel (100G, ice):
      - refactor mailbox overflow detection to support Scalable IOV
      - GNSS interface optimization
    - Intel (i40e):
      - support XDP multi-buffer
    - nVidia/Mellanox:
      - add the support for linux bridge multicast offload
      - enable TC offload for egress and engress MACVLAN over bond
      - add support for VxLAN GBP encap/decap flows offload
      - extend packet offload to fully support libreswan
      - support tunnel mode in mlx5 IPsec packet offload
      - extend XDP multi-buffer support
      - support MACsec VLAN offload
      - add support for dynamic msix vectors allocation
      - drop RX page_cache and fully use page_pool
      - implement thermal zone to report NIC temperature
    - Netronome/Corigine:
      - add support for multi-zone conntrack offload
    - Solarflare/Xilinx:
      - support offloading TC VLAN push/pop actions to the MAE
      - support TC decap rules
      - support unicast PTP
 
  - Other NICs:
    - Broadcom (bnxt): enforce software based freq adjustments only
 		on shared PHC NIC
    - RealTek (r8169): refactor to addess ASPM issues during NAPI poll.
    - Micrel (lan8841): add support for PTP_PF_PEROUT
    - Cadence (macb): enable PTP unicast
    - Engleder (tsnep): add XDP socket zero-copy support
    - virtio-net: implement exact header length guest feature
    - veth: add page_pool support for page recycling
    - vxlan: add MDB data path support
    - gve: add XDP support for GQI-QPL format
    - geneve: accept every ethertype
    - macvlan: allow some packets to bypass broadcast queue
    - mana: add support for jumbo frame
 
  - Ethernet high-speed switches:
    - Microchip (sparx5): Add support for TC flower templates.
 
  - Ethernet embedded switches:
    - Broadcom (b54):
      - configure 6318 and 63268 RGMII ports
    - Marvell (mv88e6xxx):
      - faster C45 bus scan
    - Microchip:
      - lan966x:
        - add support for IS1 VCAP
        - better TX/RX from/to CPU performances
      - ksz9477: add ETS Qdisc support
      - ksz8: enhance static MAC table operations and error handling
      - sama7g5: add PTP capability
    - NXP (ocelot):
      - add support for external ports
      - add support for preemptible traffic classes
    - Texas Instruments:
      - add CPSWxG SGMII support for J7200 and J721E
 
  - Intel WiFi (iwlwifi):
    - preparation for Wi-Fi 7 EHT and multi-link support
    - EHT (Wi-Fi 7) sniffer support
    - hardware timestamping support for some devices/firwmares
    - TX beacon protection on newer hardware
 
  - Qualcomm 802.11ax WiFi (ath11k):
    - MU-MIMO parameters support
    - ack signal support for management packets
 
  - RealTek WiFi (rtw88):
    - SDIO bus support
    - better support for some SDIO devices
      (e.g. MAC address from efuse)
 
  - RealTek WiFi (rtw89):
    - HW scan support for 8852b
    - better support for 6 GHz scanning
    - support for various newer firmware APIs
    - framework firmware backwards compatibility
 
  - MediaTek WiFi (mt76):
    - P2P support
    - mesh A-MSDU support
    - EHT (Wi-Fi 7) support
    - coredump support
 
 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Merge tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Paolo Abeni:
 "Core:

   - Introduce a config option to tweak MAX_SKB_FRAGS. Increasing the
     default value allows for better BIG TCP performances

   - Reduce compound page head access for zero-copy data transfers

   - RPS/RFS improvements, avoiding unneeded NET_RX_SOFTIRQ when
     possible

   - Threaded NAPI improvements, adding defer skb free support and
     unneeded softirq avoidance

   - Address dst_entry reference count scalability issues, via false
     sharing avoidance and optimize refcount tracking

   - Add lockless accesses annotation to sk_err[_soft]

   - Optimize again the skb struct layout

   - Extends the skb drop reasons to make it usable by multiple
     subsystems

   - Better const qualifier awareness for socket casts

  BPF:

   - Add skb and XDP typed dynptrs which allow BPF programs for more
     ergonomic and less brittle iteration through data and
     variable-sized accesses

   - Add a new BPF netfilter program type and minimal support to hook
     BPF programs to netfilter hooks such as prerouting or forward

   - Add more precise memory usage reporting for all BPF map types

   - Adds support for using {FOU,GUE} encap with an ipip device
     operating in collect_md mode and add a set of BPF kfuncs for
     controlling encap params

   - Allow BPF programs to detect at load time whether a particular
     kfunc exists or not, and also add support for this in light
     skeleton

   - Bigger batch of BPF verifier improvements to prepare for upcoming
     BPF open-coded iterators allowing for less restrictive looping
     capabilities

   - Rework RCU enforcement in the verifier, add kptr_rcu and enforce
     BPF programs to NULL-check before passing such pointers into kfunc

   - Add support for kptrs in percpu hashmaps, percpu LRU hashmaps and
     in local storage maps

   - Enable RCU semantics for task BPF kptrs and allow referenced kptr
     tasks to be stored in BPF maps

   - Add support for refcounted local kptrs to the verifier for allowing
     shared ownership, useful for adding a node to both the BPF list and
     rbtree

   - Add BPF verifier support for ST instructions in
     convert_ctx_access() which will help new -mcpu=v4 clang flag to
     start emitting them

   - Add ARM32 USDT support to libbpf

   - Improve bpftool's visual program dump which produces the control
     flow graph in a DOT format by adding C source inline annotations

  Protocols:

   - IPv4: Allow adding to IPv4 address a 'protocol' tag. Such value
     indicates the provenance of the IP address

   - IPv6: optimize route lookup, dropping unneeded R/W lock acquisition

   - Add the handshake upcall mechanism, allowing the user-space to
     implement generic TLS handshake on kernel's behalf

   - Bridge: support per-{Port, VLAN} neighbor suppression, increasing
     resilience to nodes failures

   - SCTP: add support for Fair Capacity and Weighted Fair Queueing
     schedulers

   - MPTCP: delay first subflow allocation up to its first usage. This
     will allow for later better LSM interaction

   - xfrm: Remove inner/outer modes from input/output path. These are
     not needed anymore

   - WiFi:
      - reduced neighbor report (RNR) handling for AP mode
      - HW timestamping support
      - support for randomized auth/deauth TA for PASN privacy
      - per-link debugfs for multi-link
      - TC offload support for mac80211 drivers
      - mac80211 mesh fast-xmit and fast-rx support
      - enable Wi-Fi 7 (EHT) mesh support

  Netfilter:

   - Add nf_tables 'brouting' support, to force a packet to be routed
     instead of being bridged

   - Update bridge netfilter and ovs conntrack helpers to handle IPv6
     Jumbo packets properly, i.e. fetch the packet length from
     hop-by-hop extension header. This is needed for BIT TCP support

   - The iptables 32bit compat interface isn't compiled in by default
     anymore

   - Move ip(6)tables builtin icmp matches to the udptcp one. This has
     the advantage that icmp/icmpv6 match doesn't load the
     iptables/ip6tables modules anymore when iptables-nft is used

   - Extended netlink error report for netdevice in flowtables and
     netdev/chains. Allow for incrementally add/delete devices to netdev
     basechain. Allow to create netdev chain without device

  Driver API:

   - Remove redundant Device Control Error Reporting Enable, as PCI core
     has already error reporting enabled at enumeration time

   - Move Multicast DB netlink handlers to core, allowing devices other
     then bridge to use them

   - Allow the page_pool to directly recycle the pages from safely
     localized NAPI

   - Implement lockless TX queue stop/wake combo macros, allowing for
     further code de-duplication and sanitization

   - Add YNL support for user headers and struct attrs

   - Add partial YNL specification for devlink

   - Add partial YNL specification for ethtool

   - Add tc-mqprio and tc-taprio support for preemptible traffic classes

   - Add tx push buf len param to ethtool, specifies the maximum number
     of bytes of a transmitted packet a driver can push directly to the
     underlying device

   - Add basic LED support for switch/phy

   - Add NAPI documentation, stop relaying on external links

   - Convert dsa_master_ioctl() to netdev notifier. This is a
     preparatory work to make the hardware timestamping layer selectable
     by user space

   - Add transceiver support and improve the error messages for CAN-FD
     controllers

  New hardware / drivers:

   - Ethernet:
      - AMD/Pensando core device support
      - MediaTek MT7981 SoC
      - MediaTek MT7988 SoC
      - Broadcom BCM53134 embedded switch
      - Texas Instruments CPSW9G ethernet switch
      - Qualcomm EMAC3 DWMAC ethernet
      - StarFive JH7110 SoC
      - NXP CBTX ethernet PHY

   - WiFi:
      - Apple M1 Pro/Max devices
      - RealTek rtl8710bu/rtl8188gu
      - RealTek rtl8822bs, rtl8822cs and rtl8821cs SDIO chipset

   - Bluetooth:
      - Realtek RTL8821CS, RTL8851B, RTL8852BS
      - Mediatek MT7663, MT7922
      - NXP w8997
      - Actions Semi ATS2851
      - QTI WCN6855
      - Marvell 88W8997

   - Can:
      - STMicroelectronics bxcan stm32f429

  Drivers:

   - Ethernet NICs:
      - Intel (1G, icg):
         - add tracking and reporting of QBV config errors
         - add support for configuring max SDU for each Tx queue
      - Intel (100G, ice):
         - refactor mailbox overflow detection to support Scalable IOV
         - GNSS interface optimization
      - Intel (i40e):
         - support XDP multi-buffer
      - nVidia/Mellanox:
         - add the support for linux bridge multicast offload
         - enable TC offload for egress and engress MACVLAN over bond
         - add support for VxLAN GBP encap/decap flows offload
         - extend packet offload to fully support libreswan
         - support tunnel mode in mlx5 IPsec packet offload
         - extend XDP multi-buffer support
         - support MACsec VLAN offload
         - add support for dynamic msix vectors allocation
         - drop RX page_cache and fully use page_pool
         - implement thermal zone to report NIC temperature
      - Netronome/Corigine:
         - add support for multi-zone conntrack offload
      - Solarflare/Xilinx:
         - support offloading TC VLAN push/pop actions to the MAE
         - support TC decap rules
         - support unicast PTP

   - Other NICs:
      - Broadcom (bnxt): enforce software based freq adjustments only on
        shared PHC NIC
      - RealTek (r8169): refactor to addess ASPM issues during NAPI poll
      - Micrel (lan8841): add support for PTP_PF_PEROUT
      - Cadence (macb): enable PTP unicast
      - Engleder (tsnep): add XDP socket zero-copy support
      - virtio-net: implement exact header length guest feature
      - veth: add page_pool support for page recycling
      - vxlan: add MDB data path support
      - gve: add XDP support for GQI-QPL format
      - geneve: accept every ethertype
      - macvlan: allow some packets to bypass broadcast queue
      - mana: add support for jumbo frame

   - Ethernet high-speed switches:
      - Microchip (sparx5): Add support for TC flower templates

   - Ethernet embedded switches:
      - Broadcom (b54):
         - configure 6318 and 63268 RGMII ports
      - Marvell (mv88e6xxx):
         - faster C45 bus scan
      - Microchip:
         - lan966x:
            - add support for IS1 VCAP
            - better TX/RX from/to CPU performances
         - ksz9477: add ETS Qdisc support
         - ksz8: enhance static MAC table operations and error handling
         - sama7g5: add PTP capability
      - NXP (ocelot):
         - add support for external ports
         - add support for preemptible traffic classes
      - Texas Instruments:
         - add CPSWxG SGMII support for J7200 and J721E

   - Intel WiFi (iwlwifi):
      - preparation for Wi-Fi 7 EHT and multi-link support
      - EHT (Wi-Fi 7) sniffer support
      - hardware timestamping support for some devices/firwmares
      - TX beacon protection on newer hardware

   - Qualcomm 802.11ax WiFi (ath11k):
      - MU-MIMO parameters support
      - ack signal support for management packets

   - RealTek WiFi (rtw88):
      - SDIO bus support
      - better support for some SDIO devices (e.g. MAC address from
        efuse)

   - RealTek WiFi (rtw89):
      - HW scan support for 8852b
      - better support for 6 GHz scanning
      - support for various newer firmware APIs
      - framework firmware backwards compatibility

   - MediaTek WiFi (mt76):
      - P2P support
      - mesh A-MSDU support
      - EHT (Wi-Fi 7) support
      - coredump support"

* tag 'net-next-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2078 commits)
  net: phy: hide the PHYLIB_LEDS knob
  net: phy: marvell-88x2222: remove unnecessary (void*) conversions
  tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.
  net: amd: Fix link leak when verifying config failed
  net: phy: marvell: Fix inconsistent indenting in led_blink_set
  lan966x: Don't use xdp_frame when action is XDP_TX
  tsnep: Add XDP socket zero-copy TX support
  tsnep: Add XDP socket zero-copy RX support
  tsnep: Move skb receive action to separate function
  tsnep: Add functions for queue enable/disable
  tsnep: Rework TX/RX queue initialization
  tsnep: Replace modulo operation with mask
  net: phy: dp83867: Add led_brightness_set support
  net: phy: Fix reading LED reg property
  drivers: nfc: nfcsim: remove return value check of `dev_dir`
  net: phy: dp83867: Remove unnecessary (void*) conversions
  net: ethtool: coalesce: try to make user settings stick twice
  net: mana: Check if netdev/napi_alloc_frag returns single page
  net: mana: Rename mana_refill_rxoob and remove some empty lines
  net: veth: add page_pool stats
  ...
 2023-04-26 16:07:23 -07:00
Luis Chamberlain
8660484ed1 module: add debugging auto-load duplicate module support 
The finit_module() system call can in the worst case use up to more than
twice of a module's size in virtual memory. Duplicate finit_module()
system calls are non fatal, however they unnecessarily strain virtual
memory during bootup and in the worst case can cause a system to fail
to boot. This is only known to currently be an issue on systems with
larger number of CPUs.

To help debug this situation we need to consider the different sources for
finit_module(). Requests from the kernel that rely on module auto-loading,
ie, the kernel's *request_module() API, are one source of calls. Although
modprobe checks to see if a module is already loaded prior to calling
finit_module() there is a small race possible allowing userspace to
trigger multiple modprobe calls racing against modprobe and this not
seeing the module yet loaded.

This adds debugging support to the kernel module auto-loader (*request_module()
calls) to easily detect duplicate module requests. To aid with possible bootup
failure issues incurred by this, it will converge duplicates requests to a
single request. This avoids any possible strain on virtual memory during
bootup which could be incurred by duplicate module autoloading requests.

Folks debugging virtual memory abuse on bootup can and should enable
this to see what pr_warn()s come on, to see if module auto-loading is to
blame for their wores. If they see duplicates they can further debug this
by enabling the module.enable_dups_trace kernel parameter or by enabling
CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS_TRACE.

Current evidence seems to point to only a few duplicates for module
auto-loading. And so the source for other duplicates creating heavy
virtual memory pressure due to larger number of CPUs should becoming
from another place (likely udev).

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-19 17:26:01 -07:00
Arnd Bergmann
a81b1fc8ea module: stats: fix invalid_mod_bytes typo 
This was caught by randconfig builds but does not show up in
build testing without CONFIG_MODULE_DECOMPRESS:

kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:229:42: error: 'invalid_mod_byte' undeclared (first use in this function); did you mean 'invalid_mod_bytes'?
  229 |   atomic_long_add(info->compressed_len, &invalid_mod_byte);
      |                                          ^~~~~~~~~~~~~~~~
      |                                          invalid_mod_bytes

Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:36:41 -07:00
Tom Rix
9f5cab173e module: remove use of uninitialized variable len 
clang build reports
kernel/module/stats.c:307:34: error: variable
  'len' is uninitialized when used here [-Werror,-Wuninitialized]
        len = scnprintf(buf + 0, size - len,
                                        ^~~
At the start of this sequence, neither the '+ 0', nor the '- len' are needed.
So remove them and fix using 'len' uninitalized.

Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:36:24 -07:00
Arnd Bergmann
719ccd803e module: fix building stats for 32-bit targets 
The new module statistics code mixes 64-bit types and wordsized 'long'
variables, which leads to build failures on 32-bit architectures:

kernel/module/stats.c: In function 'read_file_mod_stats':
kernel/module/stats.c:291:29: error: passing argument 1 of 'atomic64_read' from incompatible pointer type [-Werror=incompatible-pointer-types]
  291 |  total_size = atomic64_read(&total_mod_size);
x86_64-linux-ld: kernel/module/stats.o: in function `read_file_mod_stats':
stats.c:(.text+0x2b2): undefined reference to `__udivdi3'

To fix this, the code has to use one of the two types consistently.

Change them all to word-size types here.

Fixes: df3e764d8e ("module: add debug stats to help identify memory pressure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:36:00 -07:00
Arnd Bergmann
635dc38314 module: stats: include uapi/linux/module.h 
MODULE_INIT_COMPRESSED_FILE is defined in the uapi header, which
is not included indirectly from the normal linux/module.h, but
has to be pulled in explicitly:

kernel/module/stats.c: In function 'mod_stat_bump_invalid':
kernel/module/stats.c:227:14: error: 'MODULE_INIT_COMPRESSED_FILE' undeclared (first use in this function)
  227 |  if (flags & MODULE_INIT_COMPRESSED_FILE)
      |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:35:50 -07:00
Luis Chamberlain
064f4536d1 module: avoid allocation if module is already present and ready 
The finit_module() system call can create unnecessary virtual memory
pressure for duplicate modules. This is because load_module() can in
the worse case allocate more than twice the size of a module in virtual
memory. This saves at least a full size of the module in wasted vmalloc
space memory by trying to avoid duplicates as soon as we can validate
the module name in the read module structure.

This can only be an issue if a system is getting hammered with userspace
loading modules. There are two ways to load modules typically on systems,
one is the kernel moduile auto-loading (*request_module*() calls in-kernel)
and the other is things like udev. The auto-loading is in-kernel, but that
pings back to userspace to just call modprobe. We already have a way to
restrict the amount of concurrent kernel auto-loads in a given time, however
that still allows multiple requests for the same module to go through
and force two threads in userspace racing to call modprobe for the same
exact module. Even though libkmod which both modprobe and udev does check
if a module is already loaded prior calling finit_module() races are
still possible and this is clearly evident today when you have multiple
CPUs.

To avoid memory pressure for such stupid cases put a stop gap for them.
The *earliest* we can detect duplicates from the modules side of things
is once we have blessed the module name, sadly after the first vmalloc
allocation. We can check for the module being present *before* a secondary
vmalloc() allocation.

There is a linear relationship between wasted virtual memory bytes and
the number of CPU counts. The reason is that udev ends up racing to call
tons of the same modules for each of the CPUs.

We can see the different linear relationships between wasted virtual
memory and CPU count during after boot in the following graph:

         +----------------------------------------------------------------------------+
    14GB |-+          +            +            +           +           *+          +-|
         |                                                          ****              |
         |                                                       ***                  |
         |                                                     **                     |
    12GB |-+                                                 **                     +-|
         |                                                 **                         |
         |                                               **                           |
         |                                             **                             |
         |                                           **                               |
    10GB |-+                                       **                               +-|
         |                                       **                                   |
         |                                     **                                     |
         |                                   **                                       |
     8GB |-+                               **                                       +-|
waste    |                               **                             ###           |
         |                             **                           ####              |
         |                           **                      #######                  |
     6GB |-+                     ****                    ####                       +-|
         |                      *                    ####                             |
         |                     *                 ####                                 |
         |                *****              ####                                     |
     4GB |-+            **               ####                                       +-|
         |            **             ####                                             |
         |          **           ####                                                 |
         |        **         ####                                                     |
     2GB |-+    **      #####                                                       +-|
         |     *    ####                                                              |
         |    * ####                                                   Before ******* |
         |  **##      +            +            +           +           After ####### |
         +----------------------------------------------------------------------------+
         0            50          100          150         200          250          300
                                          CPUs count

On the y-axis we can see gigabytes of wasted virtual memory during boot
due to duplicate module requests which just end up failing. Trying to
infer the slope this ends up being about ~463 MiB per CPU lost prior
to this patch. After this patch we only loose about ~230 MiB per CPU, for
a total savings of about ~233 MiB per CPU. This is all *just on bootup*!

On a 8vcpu 8 GiB RAM system using kdevops and testing against selftests
kmod.sh -t 0008 I see a saving in the *highest* side of memory
consumption of up to ~ 84 MiB with the Linux kernel selftests kmod
test 0008. With the new stress-ng module test I see a 145 MiB difference
in max memory consumption with 100 ops. The stress-ng module ops tests can be
pretty pathalogical -- it is not realistic, however it was used to
finally successfully reproduce issues which are only reported to happen on
system with over 400 CPUs [0] by just usign 100 ops on a 8vcpu 8 GiB RAM
system. Running out of virtual memory space is no surprise given the
above graph, since at least on x86_64 we're capped at 128 MiB, eventually
we'd hit a series of errors and once can use the above graph to
guestimate when. This of course will vary depending on the features
you have enabled. So for instance, enabling KASAN seems to make this
much worse.

The results with kmod and stress-ng can be observed and visualized below.
The time it takes to run the test is also not affected.

The kmod tests 0008:

The gnuplot is set to a range from 400000 KiB (390 Mib) - 580000 (566 Mib)
given the tests peak around that range.

cat kmod.plot
set term dumb
set output fileout
set yrange [400000:580000]
plot filein with linespoints title "Memory usage (KiB)"

Before:
root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-before.txt ^C
root@kmod ~ # sort -n -r log-0008-before.txt | head -1
528732

So ~516.33 MiB

After:

root@kmod ~ # /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > log-0008-after.txt ^C

root@kmod ~ # sort -n -r log-0008-after.txt | head -1
442516

So ~432.14 MiB

That's about 84 ~MiB in savings in the worst case. The graphs:

root@kmod ~ # gnuplot -e "filein='log-0008-before.txt'; fileout='graph-0008-before.txt'" kmod.plot
root@kmod ~ # gnuplot -e "filein='log-0008-after.txt';  fileout='graph-0008-after.txt'"  kmod.plot

root@kmod ~ # cat graph-0008-before.txt

  580000 +-----------------------------------------------------------------+
         |       +        +       +       +       +        +       +       |
  560000 |-+                                    Memory usage (KiB) ***A***-|
         |                                                                 |
  540000 |-+                                                             +-|
         |                                                                 |
         |        *A     *AA*AA*A*AA          *A*AA    A*A*A *AA*A*AA*A  A |
  520000 |-+A*A*AA  *AA*A           *A*AA*A*AA     *A*A     A          *A+-|
         |*A                                                               |
  500000 |-+                                                             +-|
         |                                                                 |
  480000 |-+                                                             +-|
         |                                                                 |
  460000 |-+                                                             +-|
         |                                                                 |
         |                                                                 |
  440000 |-+                                                             +-|
         |                                                                 |
  420000 |-+                                                             +-|
         |       +        +       +       +       +        +       +       |
  400000 +-----------------------------------------------------------------+
         0       5        10      15      20      25       30      35      40

root@kmod ~ # cat graph-0008-after.txt

  580000 +-----------------------------------------------------------------+
         |       +        +       +       +       +        +       +       |
  560000 |-+                                    Memory usage (KiB) ***A***-|
         |                                                                 |
  540000 |-+                                                             +-|
         |                                                                 |
         |                                                                 |
  520000 |-+                                                             +-|
         |                                                                 |
  500000 |-+                                                             +-|
         |                                                                 |
  480000 |-+                                                             +-|
         |                                                                 |
  460000 |-+                                                             +-|
         |                                                                 |
         |          *A              *A*A                                   |
  440000 |-+A*A*AA*A  A       A*A*AA    A*A*AA*A*AA*A*AA*A*AA*AA*A*AA*A*AA-|
         |*A           *A*AA*A                                             |
  420000 |-+                                                             +-|
         |       +        +       +       +       +        +       +       |
  400000 +-----------------------------------------------------------------+
         0       5        10      15      20      25       30      35      40

The stress-ng module tests:

This is used to run the test to try to reproduce the vmap issues
reported by David:

  echo 0 > /proc/sys/vm/oom_dump_tasks
  ./stress-ng --module 100 --module-name xfs

Prior to this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > baseline-stress-ng.txt
root@kmod ~ # sort -n -r baseline-stress-ng.txt | head -1
5046456

After this commit:
root@kmod ~ # free -k -s 1 -c 40 | grep Mem | awk '{print $3}' > after-stress-ng.txt
root@kmod ~ # sort -n -r after-stress-ng.txt | head -1
4896972

5046456 - 4896972
149484
149484/1024
145.98046875000000000000

So this commit using stress-ng reveals saving about 145 MiB in memory
using 100 ops from stress-ng which reproduced the vmap issue reported.

cat kmod.plot
set term dumb
set output fileout
set yrange [4700000:5070000]
plot filein with linespoints title "Memory usage (KiB)"

root@kmod ~ # gnuplot -e "filein='baseline-stress-ng.txt'; fileout='graph-stress-ng-before.txt'"  kmod-simple-stress-ng.plot
root@kmod ~ # gnuplot -e "filein='after-stress-ng.txt'; fileout='graph-stress-ng-after.txt'"  kmod-simple-stress-ng.plot

root@kmod ~ # cat graph-stress-ng-before.txt

           +---------------------------------------------------------------+
  5.05e+06 |-+     + A     +       +       +       +       +       +     +-|
           |         *                          Memory usage (KiB) ***A*** |
           |         *                             A                       |
     5e+06 |-+      **                            **                     +-|
           |        **                            * *    A                 |
  4.95e+06 |-+      * *                          A  *   A*               +-|
           |        * *      A       A           *  *  *  *             A  |
           |       *  *     * *     * *        *A   *  *  *      A      *  |
   4.9e+06 |-+     *  *     * A*A   * A*AA*A  A      *A    **A   **A*A  *+-|
           |       A  A*A  A    *  A       *  *      A     A *  A    * **  |
           |      *      **      **         * *              *  *    * * * |
  4.85e+06 |-+   A       A       A          **               *  *     ** *-|
           |     *                           *               * *      ** * |
           |     *                           A               * *      *  * |
   4.8e+06 |-+   *                                           * *      A  A-|
           |     *                                           * *           |
  4.75e+06 |-+  *                                            * *         +-|
           |    *                                            **            |
           |    *  +       +       +       +       +       + **    +       |
   4.7e+06 +---------------------------------------------------------------+
           0       5       10      15      20      25      30      35      40

root@kmod ~ # cat graph-stress-ng-after.txt

           +---------------------------------------------------------------+
  5.05e+06 |-+     +       +       +       +       +       +       +     +-|
           |                                    Memory usage (KiB) ***A*** |
           |                                                               |
     5e+06 |-+                                                           +-|
           |                                                               |
  4.95e+06 |-+                                                           +-|
           |                                                               |
           |                                                               |
   4.9e+06 |-+                                      *AA                  +-|
           |  A*AA*A*A  A  A*AA*AA*A*AA*A  A  A  A*A   *AA*A*A  A  A*AA*AA |
           |  *      * **  *            *  *  ** *            ***  *       |
  4.85e+06 |-+*       ***  *            * * * ***             A *  *     +-|
           |  *       A *  *             ** * * A               *  *       |
           |  *         *  *             *  **                  *  *       |
   4.8e+06 |-+*         *  *             A   *                  *  *     +-|
           | *          * *                  A                  * *        |
  4.75e+06 |-*          * *                                     * *      +-|
           | *          * *                                     * *        |
           | *     +    * *+       +       +       +       +    * *+       |
   4.7e+06 +---------------------------------------------------------------+
           0       5       10      15      20      25      30      35      40

[0] https://lkml.kernel.org/r/20221013180518.217405-1-david@redhat.com

Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:15:24 -07:00
Luis Chamberlain
df3e764d8e module: add debug stats to help identify memory pressure 
Loading modules with finit_module() can end up using vmalloc(), vmap()
and vmalloc() again, for a total of up to 3 separate allocations in the
worst case for a single module. We always kernel_read*() the module,
that's a vmalloc(). Then vmap() is used for the module decompression,
and if so the last read buffer is freed as we use the now decompressed
module buffer to stuff data into our copy module. The last allocation is
specific to each architectures but pretty much that's generally a series
of vmalloc() calls or a variation of vmalloc to handle ELF sections with
special permissions.

Evaluation with new stress-ng module support [1] with just 100 ops
is proving that you can end up using GiBs of data easily even with all
care we have in the kernel and userspace today in trying to not load modules
which are already loaded. 100 ops seems to resemble the sort of pressure a
system with about 400 CPUs can create on module loading. Although issues
relating to duplicate module requests due to each CPU inucurring a new
module reuest is silly and some of these are being fixed, we currently lack
proper tooling to help diagnose easily what happened, when it happened
and who likely is to blame -- userspace or kernel module autoloading.

Provide an initial set of stats which use debugfs to let us easily scrape
post-boot information about failed loads. This sort of information can
be used on production worklaods to try to optimize *avoiding* redundant
memory pressure using finit_module().

There's a few examples that can be provided:

A 255 vCPU system without the next patch in this series applied:

Startup finished in 19.143s (kernel) + 7.078s (userspace) = 26.221s
graphical.target reached after 6.988s in userspace

And 13.58 GiB of virtual memory space lost due to failed module loading:

root@big ~ # cat /sys/kernel/debug/modules/stats
         Mods ever loaded       67
     Mods failed on kread       0
Mods failed on decompress       0
  Mods failed on becoming       0
      Mods failed on load       1411
        Total module size       11464704
      Total mod text size       4194304
       Failed kread bytes       0
  Failed decompress bytes       0
    Failed becoming bytes       0
        Failed kmod bytes       14588526272
 Virtual mem wasted bytes       14588526272
         Average mod size       171115
    Average mod text size       62602
  Average fail load bytes       10339140
Duplicate failed modules:
              module-name        How-many-times                    Reason
                kvm_intel                   249                      Load
                      kvm                   249                      Load
                irqbypass                     8                      Load
         crct10dif_pclmul                   128                      Load
      ghash_clmulni_intel                    27                      Load
             sha512_ssse3                    50                      Load
           sha512_generic                   200                      Load
              aesni_intel                   249                      Load
              crypto_simd                    41                      Load
                   cryptd                   131                      Load
                    evdev                     2                      Load
                serio_raw                     1                      Load
               virtio_pci                     3                      Load
                     nvme                     3                      Load
                nvme_core                     3                      Load
    virtio_pci_legacy_dev                     3                      Load
    virtio_pci_modern_dev                     3                      Load
                   t10_pi                     3                      Load
                   virtio                     3                      Load
             crc32_pclmul                     6                      Load
           crc64_rocksoft                     3                      Load
             crc32c_intel                    40                      Load
              virtio_ring                     3                      Load
                    crc64                     3                      Load

The following screen shot, of a simple 8vcpu 8 GiB KVM guest with the
next patch in this series applied, shows 226.53 MiB are wasted in virtual
memory allocations which due to duplicate module requests during boot.
It also shows an average module memory size of 167.10 KiB and an an
average module .text + .init.text size of 61.13 KiB. The end shows all
modules which were detected as duplicate requests and whether or not
they failed early after just the first kernel_read*() call or late after
we've already allocated the private space for the module in
layout_and_allocate(). A system with module decompression would reveal
more wasted virtual memory space.

We should put effort now into identifying the source of these duplicate
module requests and trimming these down as much possible. Larger systems
will obviously show much more wasted virtual memory allocations.

root@kmod ~ # cat /sys/kernel/debug/modules/stats
         Mods ever loaded       67
     Mods failed on kread       0
Mods failed on decompress       0
  Mods failed on becoming       83
      Mods failed on load       16
        Total module size       11464704
      Total mod text size       4194304
       Failed kread bytes       0
  Failed decompress bytes       0
    Failed becoming bytes       228959096
        Failed kmod bytes       8578080
 Virtual mem wasted bytes       237537176
         Average mod size       171115
    Average mod text size       62602
  Avg fail becoming bytes       2758544
  Average fail load bytes       536130
Duplicate failed modules:
              module-name        How-many-times                    Reason
                kvm_intel                     7                  Becoming
                      kvm                     7                  Becoming
                irqbypass                     6           Becoming & Load
         crct10dif_pclmul                     7           Becoming & Load
      ghash_clmulni_intel                     7           Becoming & Load
             sha512_ssse3                     6           Becoming & Load
           sha512_generic                     7           Becoming & Load
              aesni_intel                     7                  Becoming
              crypto_simd                     7           Becoming & Load
                   cryptd                     3           Becoming & Load
                    evdev                     1                  Becoming
                serio_raw                     1                  Becoming
                     nvme                     3                  Becoming
                nvme_core                     3                  Becoming
                   t10_pi                     3                  Becoming
               virtio_pci                     3                  Becoming
             crc32_pclmul                     6           Becoming & Load
           crc64_rocksoft                     3                  Becoming
             crc32c_intel                     3                  Becoming
    virtio_pci_modern_dev                     2                  Becoming
    virtio_pci_legacy_dev                     1                  Becoming
                    crc64                     2                  Becoming
                   virtio                     2                  Becoming
              virtio_ring                     2                  Becoming

[0] https://github.com/ColinIanKing/stress-ng.git
[1] echo 0 > /proc/sys/vm/oom_dump_tasks
    ./stress-ng --module 100 --module-name xfs

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:15:24 -07:00
Luis Chamberlain
f71afa6a42 module: extract patient module check into helper 
The patient module check inside add_unformed_module() is large
enough as we need it. It is a bit hard to read too, so just
move it to a helper and do the inverse checks first to help
shift the code and make it easier to read. The new helper then
is module_patient_check_exists().

To make this work we need to mvoe the finished_loading() up,
we do that without making any functional changes to that routine.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:15:24 -07:00
Luis Chamberlain
25a1b5b518 modules/kmod: replace implementation with a semaphore 
Simplify the concurrency delimiter we use for kmod with the semaphore.
I had used the kmod strategy to try to implement a similar concurrency
delimiter for the kernel_read*() calls from the finit_module() path
so to reduce vmalloc() memory pressure. That effort didn't provide yet
conclusive results, but one thing that became clear is we can use
the suggested alternative solution with semaphores which Linus hinted
at instead of using the atomic / wait strategy.

I've stress tested this with kmod test 0008:

time /data/linux-next/tools/testing/selftests/kmod/kmod.sh -t 0008

And I get only a *slight* delay. That delay however is small, a few
seconds for a full test loop run that runs 150 times, for about ~30-40
seconds. The small delay is worth the simplfication IMHO.

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-18 11:15:24 -07:00
Luis Chamberlain
430bb0d1c3 module: fix kmemleak annotations for non init ELF sections 
Commit ac3b432839 ("module: replace module_layout with module_memory")
reworked the way to handle memory allocations to make it clearer. But it
lost in translation how we handled kmemleak_ignore() or kmemleak_not_leak()
for different ELF sections.

Fix this and clarify the comments a bit more. Contrary to the old way
of using kmemleak_ignore() for init.* ELF sections we stick now only to
kmemleak_not_leak() as per suggestion by Catalin Marinas so to avoid
any false positives and simplify the code.

Fixes: ac3b432839 ("module: replace module_layout with module_memory")
Reported-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-14 09:36:22 -07:00
Tiezhu Yang
0a3bf86092 module: Ignore L0 and rename is_arm_mapping_symbol() 
The L0 symbol is generated when build module on LoongArch, ignore it in
modpost and when looking at module symbols, otherwise we can not see the
expected call trace.

Now is_arm_mapping_symbol() is not only for ARM, in order to reflect the
reality, rename is_arm_mapping_symbol() to is_mapping_symbol().

This is related with commit c17a253870 ("mksysmap: Fix the mismatch of
'L0' symbols in System.map").

(1) Simple test case

  [loongson@linux hello]$ cat hello.c
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/printk.h>

  static void test_func(void)
  {
  	  pr_info("This is a test\n");
	  dump_stack();
  }

  static int __init hello_init(void)
  {
	  pr_warn("Hello, world\n");
	  test_func();

	  return 0;
  }

  static void __exit hello_exit(void)
  {
	  pr_warn("Goodbye\n");
  }

  module_init(hello_init);
  module_exit(hello_exit);
  MODULE_LICENSE("GPL");
  [loongson@linux hello]$ cat Makefile
  obj-m:=hello.o

  ccflags-y += -g -Og

  all:
	  make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) modules
  clean:
	  make -C /lib/modules/$(shell uname -r)/build/ M=$(PWD) clean

(2) Test environment

system: LoongArch CLFS 5.5
https://github.com/sunhaiyong1978/CLFS-for-LoongArch/releases/tag/5.0
It needs to update grub to avoid booting error "invalid magic number".

kernel: 6.3-rc1 with loongson3_defconfig + CONFIG_DYNAMIC_FTRACE=y

(3) Test result

Without this patch:

  [root@linux hello]# insmod hello.ko
  [root@linux hello]# dmesg
  ...
  Hello, world
  This is a test
  ...
  Call Trace:
  [<9000000000223728>] show_stack+0x68/0x18c
  [<90000000013374cc>] dump_stack_lvl+0x60/0x88
  [<ffff800002050028>] L0\x01+0x20/0x2c [hello]
  [<ffff800002058028>] L0\x01+0x20/0x30 [hello]
  [<900000000022097c>] do_one_initcall+0x88/0x288
  [<90000000002df890>] do_init_module+0x54/0x200
  [<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
  [<90000000013382e8>] do_syscall+0x7c/0x94
  [<9000000000221e3c>] handle_syscall+0xbc/0x158

With this patch:

  [root@linux hello]# insmod hello.ko
  [root@linux hello]# dmesg
  ...
  Hello, world
  This is a test
  ...
  Call Trace:
  [<9000000000223728>] show_stack+0x68/0x18c
  [<90000000013374cc>] dump_stack_lvl+0x60/0x88
  [<ffff800002050028>] test_func+0x28/0x34 [hello]
  [<ffff800002058028>] hello_init+0x28/0x38 [hello]
  [<900000000022097c>] do_one_initcall+0x88/0x288
  [<90000000002df890>] do_init_module+0x54/0x200
  [<90000000002e1e18>] __do_sys_finit_module+0xc4/0x114
  [<90000000013382e8>] do_syscall+0x7c/0x94
  [<9000000000221e3c>] handle_syscall+0xbc/0x158

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Tested-by: Youling Tang <tangyouling@loongson.cn> # for LoongArch
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-13 17:15:50 -07:00
Tiezhu Yang
987d2e0aaa module: Move is_arm_mapping_symbol() to module_symbol.h 
In order to avoid duplicated code, move is_arm_mapping_symbol() to
include/linux/module_symbol.h, then remove is_arm_mapping_symbol()
in the other places.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-13 17:15:49 -07:00
Tiezhu Yang
87e5b1e8f2 module: Sync code of is_arm_mapping_symbol() 
After commit 2e3a10a155 ("ARM: avoid ARM binutils leaking ELF local
symbols") and commit d6b732666a ("modpost: fix undefined behavior of
is_arm_mapping_symbol()"), many differences of is_arm_mapping_symbol()
exist in kernel/module/kallsyms.c and scripts/mod/modpost.c, just sync
the code to keep consistent.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-04-13 17:15:49 -07:00
Jiri Olsa
d099f594ad kallsyms: Disable preemption for find_kallsyms_symbol_value 
Artem reported suspicious RCU usage [1]. The reason is that verifier
calls find_kallsyms_symbol_value with preemption enabled which will
trigger suspicious RCU usage warning in rcu_dereference_sched call.

Disabling preemption in find_kallsyms_symbol_value and adding
__find_kallsyms_symbol_value function.

Fixes: 31bf1dbccf ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Reported-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/bpf/20230403220254.2191240-1-jolsa@kernel.org

[1] https://lore.kernel.org/bpf/ZBrPMkv8YVRiWwCR@samus.usersys.redhat.com/
 2023-04-04 17:11:59 -07:00
Jim Cromie
33c951f629 module: already_uses() - reduce pr_debug output volume 
already_uses() is unnecessarily chatty.

`modprobe i915` yields 491 messages like:

  [   64.108744] i915 uses drm!

This is a normal situation, and isn't worth all the log entries.

NOTE: I've preserved the "does not use %s" messages, which happens
less often, but does happen.  Its not clear to me what it tells a
reader, or what info might improve the pr_debug's utility.

[ 6847.584999] main:already_uses:569: amdgpu does not use ttm!
[ 6847.585001] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585014] main:already_uses:569: amdgpu does not use drm!
[ 6847.585016] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585024] main:already_uses:569: amdgpu does not use drm_display_helper!
[ 6847.585025] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585084] main:already_uses:569: amdgpu does not use drm_kms_helper!
[ 6847.585086] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585175] main:already_uses:569: amdgpu does not use drm_buddy!
[ 6847.585176] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585202] main:already_uses:569: amdgpu does not use i2c_algo_bit!
[ 6847.585204] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585249] main:already_uses:569: amdgpu does not use gpu_sched!
[ 6847.585250] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585314] main:already_uses:569: amdgpu does not use video!
[ 6847.585315] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585409] main:already_uses:569: amdgpu does not use iommu_v2!
[ 6847.585410] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585816] main:already_uses:569: amdgpu does not use drm_ttm_helper!
[ 6847.585818] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6848.762268] dyndbg: add-module: amdgpu.2533 sites

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:09 -07:00
Jim Cromie
66a2301edf module: add section-size to move_module pr_debug 
move_module() pr_debug's "Final section addresses for $modname".
Add section addresses to the message, for anyone looking at these.

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:09 -07:00
Jim Cromie
b10addf37b module: add symbol-name to pr_debug Absolute symbol 
The pr_debug("Absolute symbol" ..) reports value, (which is usually
0), but not the name, which is more informative.  So add it.

no functional changes

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:09 -07:00
Jim Cromie
6ed81802d4 module: in layout_sections, move_module: add the modname 
layout_sections() and move_module() each issue ~50 messages for each
module loaded.  Add mod-name into their 2 header lines, to help the
reader find his module.

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:09 -07:00
Luis Chamberlain
25be451aa4 module: fold usermode helper kmod into modules directory 
The kernel/kmod.c is already only built if we enabled modules, so
just stuff it under kernel/module/kmod.c and unify the MAINTAINERS
file for it.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
3d40bb903e module: merge remnants of setup_load_info() to elf validation 
The setup_load_info() was actually had ELF validation checks of its
own. To later cache useful variables as an secondary step just means
looping again over the ELF sections we just validated. We can simply
keep tabs of the key sections of interest as we validate the module
ELF section in one swoop, so do that and merge the two routines
together.

Expand a bit on the documentation / intent / goals.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
1bb49db991 module: move more elf validity checks to elf_validity_check() 
The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
c7ee8aebf6 module: add stop-grap sanity check on module memcpy() 
The integrity of the struct module we load is important, and although
our ELF validator already checks that the module section must match
struct module, add a stop-gap check before we memcpy() the final minted
module. This also makes those inspecting the code what the goal is.

While at it, clarify the goal behind updating the sh_addr address.
The current comment is pretty misleading.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
46752820f9 module: add sanity check for ELF module section 
The ELF ".gnu.linkonce.this_module" section is special, it is what we
use to construct the struct module __this_module, which THIS_MODULE
points to. When userspace loads a module we always deal first with a
copy of the userspace buffer, and twiddle with the userspace copy's
version of the struct module. Eventually we allocate memory to do a
memcpy() of that struct module, under the assumption that the module
size is right. But we have no validity checks against the size or
the requirements for the section.

Add some validity checks for the special module section early and while
at it, cache the module section index early, so we don't have to do that
later.

While at it, just move over the assigment of the info->mod to make the
code clearer. The validity checker also adds an explicit size check to
ensure the module section size matches the kernel's run time size for
sizeof(struct module). This should prevent sloppy loads of modules
which are built today *without* actually increasing the size of
the struct module. A developer today can for example expand the size
of struct module, rebuild a directoroy 'make fs/xfs/' for example and
then try to insmode the driver there. That module would in effect have
an incorrect size. This new size check would put a stop gap against such
mistakes.

This also makes the entire goal of ".gnu.linkonce.this_module" pretty
clear. Before this patch verification of the goal / intent required some
Indian Jones whips, torches and cleaning up big old spider webs.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
419e1a20f7 module: rename check_module_license_and_versions() to check_export_symbol_versions() 
This makes the routine easier to understand what the check its checking for.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
72f08b3cc6 module: converge taint work together 
Converge on a compromise: so long as we have a module hit our linked
list of modules we taint. That is, the module was about to become live.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
c3bbf62ebf module: move signature taint to module_augment_kernel_taints() 
Just move the signature taint into the helper:

  module_augment_kernel_taints()

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
a12b94511c module: move tainting until after a module hits our linked list 
It is silly to have taints spread out all over, we can just compromise
and add them if the module ever hit our linked list. Our sanity checkers
should just prevent crappy drivers / bogus ELF modules / etc and kconfig
options should be enough to let you *not* load things you don't want.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
437c1f9cc6 module: split taint adding with info checking 
check_modinfo() actually does two things:

 a) sanity checks, some of which are fatal, and so we
    prevent the user from completing trying to load a module
 b) taints the kernel

The taints are pretty heavy handed because we're tainting the kernel
*before* we ever even get to load the module into the modules linked
list. That is, it it can fail for other reasons later as we review the
module's structure.

But this commit makes no functional changes, it just makes the intent
clearer and splits the code up where needed to make that happen.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
ed52cabecb module: split taint work out of check_modinfo_livepatch() 
The work to taint the kernel due to a module should be split
up eventually. To aid with this, split up the tainting on
check_modinfo_livepatch().

This let's us bring more early checks together which do return
a value, and makes changes easier to read later where we stuff
all the work to do the taints in one single routine.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
ad8d3a36e9 module: rename set_license() to module_license_taint_check() 
The set_license() routine would seem to a reader to do some sort of
setting, but it does not. It just adds a taint if the license is
not set or proprietary.

This makes what the code is doing clearer, so much we can remove
the comment about it.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:08 -07:00
Luis Chamberlain
02da2cbab4 module: move check_modinfo() early to early_mod_check() 
This moves check_modinfo() to early_mod_check(). This
doesn't make any functional changes either, as check_modinfo()
was the first call on layout_and_allocate(), so we're just
moving it back one routine and at the end.

This let's us keep separate the checkers from the allocator.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2023-03-24 11:33:06 -07:00