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Commit Graph

914195 Commits

Author SHA1 Message Date
Somala Swaraj
43afe4d366 ipc/mqueue.c: fix a brace coding style issue
Signed-off-by: somala swaraj <somalaswaraj@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200301135530.18340-1-somalaswaraj@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:45 -07:00
Qiujun Huang
29b46fa3dc lib/Kconfig.debug: fix a typo "capabilitiy" -> "capability"
s/capabilitiy/capability

Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1585818594-27373-1-git-send-email-hqjagain@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
ef065653e5 ubsan: include bug type in report header
When syzbot tries to figure out how to deduplicate bug reports, it prefers
seeing a hint about a specific bug type (we can do better than just
"UBSAN").  This lifts the handler reason into the UBSAN report line that
includes the file path that tripped a check.  Unfortunately, UBSAN does
not provide function names.

Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-7-keescook@chromium.org
Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
1d2252fab9 kasan: unset panic_on_warn before calling panic()
As done in the full WARN() handler, panic_on_warn needs to be cleared
before calling panic() to avoid recursive panics.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-6-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
1d28c8d6d0 ubsan: check panic_on_warn
Syzkaller expects kernel warnings to panic when the panic_on_warn sysctl
is set.  More work is needed here to have UBSan reuse the WARN
infrastructure, but for now, just check the flag manually.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: https://lore.kernel.org/lkml/CACT4Y+bsLJ-wFx_TaXqax3JByUOWB3uk787LsyMVcfW6JzzGvg@mail.gmail.com
Link: http://lkml.kernel.org/r/20200227193516.32566-5-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
ae2e1aad3e drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks
Adds LKDTM tests for arithmetic overflow (both signed and unsigned), as
well as array bounds checking.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-4-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
277a10850f ubsan: split "bounds" checker from other options
In order to do kernel builds with the bounds checker individually
available, introduce CONFIG_UBSAN_BOUNDS, with the remaining options under
CONFIG_UBSAN_MISC.

For example, using this, we can start to expand the coverage syzkaller is
providing.  Right now, all of UBSan is disabled for syzbot builds because
taken as a whole, it is too noisy.  This will let us focus on one feature
at a time.

For the bounds checker specifically, this provides a mechanism to
eliminate an entire class of array overflows with close to zero
performance overhead (I cannot measure a difference).  In my (mostly)
defconfig, enabling bounds checking adds ~4200 checks to the kernel.
Performance changes are in the noise, likely due to the branch predictors
optimizing for the non-fail path.

Some notes on the bounds checker:

- it does not instrument {mem,str}*()-family functions, it only
  instruments direct indexed accesses (e.g. "foo[i]"). Dealing with
  the {mem,str}*()-family functions is a work-in-progress around
  CONFIG_FORTIFY_SOURCE[1].

- it ignores flexible array members, including the very old single
  byte (e.g. "int foo[1];") declarations. (Note that GCC's
  implementation appears to ignore _all_ trailing arrays, but Clang only
  ignores empty, 0, and 1 byte arrays[2].)

[1] https://github.com/KSPP/linux/issues/6
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92589

Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Link: http://lkml.kernel.org/r/20200227193516.32566-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Kees Cook
0887a7ebc9 ubsan: add trap instrumentation option
Patch series "ubsan: Split out bounds checker", v5.

This splits out the bounds checker so it can be individually used.  This
is enabled in Android and hopefully for syzbot.  Includes LKDTM tests for
behavioral corner-cases (beyond just the bounds checker), and adjusts
ubsan and kasan slightly for correct panic handling.

This patch (of 6):

The Undefined Behavior Sanitizer can operate in two modes: warning
reporting mode via lib/ubsan.c handler calls, or trap mode, which uses
__builtin_trap() as the handler.  Using lib/ubsan.c means the kernel image
is about 5% larger (due to all the debugging text and reporting structures
to capture details about the warning conditions).  Using the trap mode,
the image size changes are much smaller, though at the loss of the
"warning only" mode.

In order to give greater flexibility to system builders that want minimal
changes to image size and are prepared to deal with kernel code being
aborted and potentially destabilizing the system, this introduces
CONFIG_UBSAN_TRAP.  The resulting image sizes comparison:

   text    data     bss       dec       hex     filename
19533663   6183037  18554956  44271656  2a38828 vmlinux.stock
19991849   7618513  18874448  46484810  2c54d4a vmlinux.ubsan
19712181   6284181  18366540  44362902  2a4ec96 vmlinux.ubsan-trap

CONFIG_UBSAN=y:      image +4.8% (text +2.3%, data +18.9%)
CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%)

Additionally adjusts the CONFIG_UBSAN Kconfig help for clarity and removes
the mention of non-existing boot param "ubsan_handle".

Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Link: http://lkml.kernel.org/r/20200227193516.32566-2-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Krzysztof Kozlowski
7baf219982 init/Kconfig: clean up ANON_INODES and old IO schedulers options
CONFIG_ANON_INODES is gone since commit 5dd50aaeb1 ("Make anon_inodes
unconditional").

CONFIG_CFQ_GROUP_IOSCHED was replaced with CONFIG_BFQ_GROUP_IOSCHED in
commit f382fb0bce ("block: remove legacy IO schedulers").

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20200130192419.3026-1-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Gustavo A. R. Silva
6524d79413 kernel/gcov/fs.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied.  As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200302224851.GA26467@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Gustavo A. R. Silva
7ff87182d1 gcov: gcc_3_4: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied.  As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200302224501.GA14175@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Gustavo A. R. Silva
fba4168ede gcov: gcc_4_7: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied.  As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200213152241.GA877@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Qiujun Huang
06d4f8152a kernel/kmod.c: fix a typo "assuems" -> "assumes"
There is a typo in comment.  Fix it.  s/assuems/assumes/

Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/1585891029-6450-1-git-send-email-hqjagain@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Colin Ian King
5404e7e0ac reiserfs: clean up several indentation issues
There are several places where code is indented incorrectly. Fix these.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200325135018.113431-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Will Deacon
0bd476e6c6 kallsyms: unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()
kallsyms_lookup_name() and kallsyms_on_each_symbol() are exported to
modules despite having no in-tree users and being wide open to abuse by
out-of-tree modules that can use them as a method to invoke arbitrary
non-exported kernel functions.

Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol().

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: http://lkml.kernel.org/r/20200221114404.14641-4-will@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Will Deacon
d8a84d33a4 samples/hw_breakpoint: drop use of kallsyms_lookup_name()
The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad ("hw-breakpoints: Fix broken hw-breakpoint sample module").

In preparation for un-exporting this symbol, switch the test over to using
__symbol_get(), which can be used to place breakpoints on exported
symbols.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Will Deacon
4800314e19 samples/hw_breakpoint: drop HW_BREAKPOINT_R when reporting writes
Patch series "Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()".

Despite having just a single modular in-tree user that I could spot,
kallsyms_lookup_name() is exported to modules and provides a mechanism
for out-of-tree modules to access and invoke arbitrary, non-exported
kernel symbols when kallsyms is enabled.

This patch series fixes up that one user and unexports the symbol along
with kallsyms_on_each_symbol(), since that could also be abused in a
similar manner.

I would like to avoid out-of-tree modules being easily able to call
functions that are not exported.  kallsyms_lookup_name() makes this
trivial to the point that there is very little incentive to rework these
modules to either use upstream interfaces correctly or propose
functionality which may be otherwise missing upstream.  Both of these
latter solutions would be pre-requisites to upstreaming these modules, and
the current state of things actively discourages that approach.

The background here is that we are aiming for Android devices to be able
to use a generic binary kernel image closely following upstream, with any
vendor extensions coming in as kernel modules.  In this case, we (Google)
end up maintaining the binary module ABI within the scope of a single LTS
kernel.  Monitoring and managing the ABI surface is not feasible if it
effectively includes all data and functions via kallsyms_lookup_name().
Of course, we could just carry this patch in the Android kernel tree, but
we're aiming to carry as little as possible (ideally nothing) and I think
it's a sensible change in its own right.  I'm surprised you object to it,
in all honesty.

Now, you could turn around and say "that's not upstream's problem", but it
still seems highly undesirable to me to have an upstream bypass for
exported symbols that isn't even used by upstream modules.  It's ripe for
abuse and encourages people to work outside of the upstream tree.  The
usual rule is that we don't export symbols without a user in the tree and
that seems especially relevant in this case.

Joe Lawrence said:

: FWIW, kallsyms was historically used by the out-of-tree kpatch support
: module to resolve external symbols as well as call set_memory_r{w,o}()
: API.  All of that support code has been merged upstream, so modern kpatch
: modules* no longer leverage kallsyms by default.
:
: That said, there are still some users who still use the deprecated support
: module with newer kernels, but that is not officially supported by the
: project.

This patch (of 3):

Given the name of a kernel symbol, the 'data_breakpoint' test claims to
"report any write operations on the kernel symbol".  However, it creates
the breakpoint using both HW_BREAKPOINT_W and HW_BREAKPOINT_R, which menas
it also fires for read access.

Drop HW_BREAKPOINT_R from the breakpoint attributes.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Link: http://lkml.kernel.org/r/20200221114404.14641-2-will@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Alexey Dobriyan
aa0d1564b1 fs/binfmt_elf.c: don't free interpreter's ELF pheaders on common path
Static executables don't need to free NULL pointer.

It doesn't matter really because static executable is not common scenario
but do it anyway out of pedantry.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200219185330.GA4933@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Alexey Dobriyan
0693ffebcf fs/binfmt_elf.c: allocate less for static executable
PT_INTERP ELF header can be spared if executable is static.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200219185012.GB4871@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Alexey Dobriyan
c69bcc932e fs/binfmt_elf.c: delete "loc" variable
"loc" variable became just a wrapper for PT_INTERP ELF header after main
ELF header was moved to "bprm->buf".  Delete it.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200219184847.GA4871@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Jason Baron
efcdd350d1 fs/epoll: make nesting accounting safe for -rt kernel
Davidlohr Bueso pointed out that when CONFIG_DEBUG_LOCK_ALLOC is set
ep_poll_safewake() can take several non-raw spinlocks after disabling
interrupts.  Since a spinlock can block in the -rt kernel, we can't take a
spinlock after disabling interrupts.  So let's re-work how we determine
the nesting level such that it plays nicely with the -rt kernel.

Let's introduce a 'nests' field in struct eventpoll that records the
current nesting level during ep_poll_callback().  Then, if we nest again
we can find the previous struct eventpoll that we were called from and
increase our count by 1.  The 'nests' field is protected by
ep->poll_wait.lock.

I've also moved the visited field to reduce the size of struct eventpoll
from 184 bytes to 176 bytes on x86_64 for !CONFIG_DEBUG_LOCK_ALLOC, which
is typical for a production config.

Reported-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Roman Penyaev <rpenyaev@suse.de>
Cc: Eric Wong <normalperson@yhbt.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: http://lkml.kernel.org/r/1582739816-13167-1-git-send-email-jbaron@akamai.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Roman Penyaev
282144e04b kselftest: introduce new epoll test case
This testcase repeats epollbug.c from the bug:

  https://bugzilla.kernel.org/show_bug.cgi?id=205933

What it tests?  It tests the race between epoll_ctl() and epoll_wait().
New event mask passed to epoll_ctl() triggers wake up, which can be missed
because of the bug described in the link.  Reproduction is 100%, so easy
to fix.  Kudos, Max, for wonderful test case.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Max Neunhoeffer <max@arangodb.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Christopher Kohlhoff <chris.kohlhoff@clearpool.io>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jes Sorensen <jes.sorensen@gmail.com>
Link: http://lkml.kernel.org/r/20200214170211.561524-2-rpenyaev@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Joe Perches
16b7f3c899 checkpatch: avoid warning about uninitialized_var()
WARNING: function definition argument 'flags' should also have an identifier name
#26: FILE: drivers/tty/serial/sh-sci.c:1348:
+       unsigned long uninitialized_var(flags);

Special-case uninitialized_var() to prevent this.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/7db7944761b0bd88c70eb17d4b7f40fe589e14ed.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:44 -07:00
Lubomir Rintel
50c9290021 checkpatch: check proper licensing of Devicetree bindings
According to Devicetree maintainers (see Link: below), the Devicetree
binding documents are preferrably licensed (GPL-2.0-only OR BSD-2-Clause).

Let's check that.  The actual check is a bit more relaxed, to allow more
liberal but compatible licensing (e.g.  GPL-2.0-or-later OR BSD-2-Clause).

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Cc: Jonas Karlman <jonas@kwiboo.se>,
Cc: Jernej Skrabec <jernej.skrabec@siol.net>,
Cc: Mark Rutland <mark.rutland@arm.com>,
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>,
Link: https://lore.kernel.org/lkml/20200108142132.GA4830@bogus/
Link: http://lkml.kernel.org/r/20200309215153.38824-1-lkundrak@v3.sk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Joe Perches
44d303eb05 checkpatch: improve Gerrit Change-Id: test
The Gerrit Change-Id: entry is sometimes placed after a Signed-off-by:
line.  When this occurs, the Gerrit warning is not currently emitted as
the first Signed-off-by: signature sets a flag to stop looking.

Change the test to add a test for the --- patch separator and emit the
warning before any before the --- and also before any diff file name.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/2f6d5f8766fe7439a116c77ea8cc721a3f2d77a2.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Antonio Borneo
713a09de9c checkpatch: add command-line option for TAB size
Linux kernel coding style requires a size of 8 characters for both TAB and
indentation, and such value is embedded as magic value allover the
checkpatch script.

This makes hard to reuse the script by other projects with different
requirements in their coding style (e.g.  OpenOCD [1] requires TAB size of
4 characters [2]).

Replace the magic value 8 with a variable.

Add a command-line option "--tab-size" to let the user select a
TAB size value other than 8.

[1] http://openocd.org/
[2] http://openocd.org/doc/doxygen/html/stylec.html#styleformat

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Signed-off-by: Erik Ahlén <erik.ahlen@avalonenterprise.com>
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200122163852.124417-3-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Antonio Borneo
7b18496cbc checkpatch: fix multiple const * types
Commit 1574a29f8e ("checkpatch: allow multiple const * types") claims to
support repetition of pattern "const *", but it actually allows only one
extra instance.

Check the following lines
	int a(char const * const x[]);
	int b(char const * const *x);
	int c(char const * const * const x[]);
	int d(char const * const * const *x);

with command

	./scripts/checkpatch.pl --show-types -f filename

to find that only the first line passes the test, while a warning
is triggered by the other 3 lines:

	WARNING:FUNCTION_ARGUMENTS: function definition argument
	'char const * const' should also have an identifier name

The reason is that the pattern match halts at the second asterisk in the
line, thus the remaining text starting with asterisk fails to match a
valid name for a variable.

Fixed by replacing "?" (Match 1 or 0 times) with "{0,4}" (Match no more
than 4 times) in the regular expression.  Fix also the similar test for
types in unusual order.

Fixes: 1574a29f8e ("checkpatch: allow multiple const * types")
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200122163852.124417-1-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Antonio Borneo
342d3d2f13 checkpatch: fix minor typo and mixed space+tab in indentation
Fix spelling of "concatenation".
Don't use tab after space in indentation.

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200122163852.124417-2-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Joe Perches
f36d3eb89a checkpatch: prefer fallthrough; over fallthrough comments
commit 294f69e662 ("compiler_attributes.h: Add 'fallthrough' pseudo
keyword for switch/case use") added the pseudo keyword so add a test for
it to checkpatch.

Warn on a patch or use --strict for files.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/8b6c1b9031ab9f3cdebada06b8d46467f1492d68.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
John Hubbard
a8972573eb checkpatch: support "base-commit:" format
In order to support the get-lore-mbox.py tool described in [1], I ran:

    git format-patch --base=<commit> --cover-letter <revrange>

...  which generated a "base-commit: <commit-hash>" tag at the end of the
cover letter.  However, checkpatch.pl generated an error upon encounting
"base-commit:" in the cover letter:

    "ERROR: Please use git commit description style..."

...  because it found the "commit" keyword, and failed to recognize that
it was part of the "base-commit" phrase, and as such, should not be
subjected to the same commit description style rules.

Update checkpatch.pl to include a special case for "base-commit:" (at the
start of the line, possibly with some leading whitespace) so that that tag
no longer generates a checkpatch error.

[1] https://lwn.net/Articles/811528/ "Better tools for kernel
    developers"

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Link: http://lkml.kernel.org/r/20200213055004.69235-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Lubomir Rintel
c8df0ab614 checkpatch: check SPDX tags in YAML files
This adds a warning when a YAML file is lacking a SPDX header on first
line, or it uses incorrect commenting style.

Currently the only YAML files in the tree are Devicetree binding
documents.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Cc: Rob Herring <robh@kernel.org>
Link: http://lkml.kernel.org/r/20200129123356.388669-1-lkundrak@v3.sk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Joe Perches
dfa05c28ca checkpatch: remove email address comment from email address comparisons
About 2% of the last 100K commits have email addresses that include an
RFC2822 compliant comment like:

	Peter Zijlstra (Intel) <peterz@infradead.org>

checkpatch currently does a comparison of the complete name and address to
the submitted author to determine if the author has signed-off and emits a
warning if the exact email names and addresses do not match.

Unfortunately, the author email address can be written without the comment
like:

	Peter Zijlstra <peterz@infradead.org>

Add logic to compare the comment stripped email addresses to avoid this
warning.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/ebaa2f7c8f94e25520981945cddcc1982e70e072.camel@perches.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Nathan Chancellor
8306b057a8 lib/dynamic_debug.c: use address-of operator on section symbols
Clang warns:

../lib/dynamic_debug.c:1034:24: warning: array comparison always
evaluates to false [-Wtautological-compare]
        if (__start___verbose == __stop___verbose) {
                              ^
1 warning generated.

These are not true arrays, they are linker defined symbols, which are just
addresses.  Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Jason Baron <jbaron@akamai.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/894
Link: http://lkml.kernel.org/r/20200220051320.10739-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Rikard Falkeborn
295bcca849 linux/bits.h: add compile time sanity check of GENMASK inputs
GENMASK() and GENMASK_ULL() are supposed to be called with the high bit as
the first argument and the low bit as the second argument.  Mixing them
will return a mask with zero bits set.

Recent commits show getting this wrong is not uncommon, see e.g.  commit
aa4c0c9091 ("net: stmmac: Fix misuses of GENMASK macro") and commit
9bdd7bb3a8 ("clocksource/drivers/npcm: Fix misuse of GENMASK macro").

To prevent such mistakes from appearing again, add compile time sanity
checking to the arguments of GENMASK() and GENMASK_ULL().  If both
arguments are known at compile time, and the low bit is higher than the
high bit, break the build to detect the mistake immediately.

Since GENMASK() is used in declarations, BUILD_BUG_ON_ZERO() must be used
instead of BUILD_BUG_ON().

__builtin_constant_p does not evaluate is argument, it only checks if it
is a constant or not at compile time, and __builtin_choose_expr does not
evaluate the expression that is not chosen.  Therefore, GENMASK(x++, 0)
does only evaluate x++ once.

Commit 95b980d62d ("linux/bits.h: make BIT(), GENMASK(), and friends
available in assembly") made the macros in linux/bits.h available in
assembly.  Since BUILD_BUG_OR_ZERO() is not asm compatible, disable the
checks if the file is included in an asm file.

Due to bugs in GCC versions before 4.9 [0], disable the check if building
with a too old GCC compiler.

[0]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19449

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Haren Myneni <haren@us.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: lkml <linux-kernel@vger.kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200308193954.2372399-1-rikard.falkeborn@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Dan Carpenter
8f0259c27c lib/test_kmod.c: remove a NULL test
The "info" pointer has already been dereferenced so checking here is too
late.  Fortunately, we never pass NULL pointers to the
test_kmod_put_module() function so the test can simply be removed.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/20200228092452.vwkhthsn77nrxdy6@kili.mountain
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
chenqiwu
8d994cada2 lib/rbtree: fix coding style of assignments
Leave blank space between the right-hand and left-hand side of the
assignment to meet the kernel coding style better.

Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Michel Lespinasse <walken@google.com>
Link: http://lkml.kernel.org/r/1582621140-25850-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Andy Shevchenko
caa7f776cc lib/test_bitmap.c: make use of EXP2_IN_BITS
Commit 30544ed5de ("lib/bitmap: introduce bitmap_replace() helper")
introduced some new test cases to the test_bitmap.c module.  Among these
it also introduced an (unused) definition.  Let's make use of
EXP2_IN_BITS.

Reported-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Link: http://lkml.kernel.org/r/20200121151847.75223-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Qian Cai
7e23452002 percpu_counter: fix a data race at vm_committed_as
"vm_committed_as.count" could be accessed concurrently as reported by
KCSAN,

 BUG: KCSAN: data-race in __vm_enough_memory / percpu_counter_add_batch

 write to 0xffffffff9451c538 of 8 bytes by task 65879 on cpu 35:
  percpu_counter_add_batch+0x83/0xd0
  percpu_counter_add_batch at lib/percpu_counter.c:91
  __vm_enough_memory+0xb9/0x260
  dup_mm+0x3a4/0x8f0
  copy_process+0x2458/0x3240
  _do_fork+0xaa/0x9f0
  __do_sys_clone+0x125/0x160
  __x64_sys_clone+0x70/0x90
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 read to 0xffffffff9451c538 of 8 bytes by task 66773 on cpu 19:
  __vm_enough_memory+0x199/0x260
  percpu_counter_read_positive at include/linux/percpu_counter.h:81
  (inlined by) __vm_enough_memory at mm/util.c:839
  mmap_region+0x1b2/0xa10
  do_mmap+0x45c/0x700
  vm_mmap_pgoff+0xc0/0x130
  ksys_mmap_pgoff+0x6e/0x300
  __x64_sys_mmap+0x33/0x40
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The read is outside percpu_counter::lock critical section which results in
a data race.  Fix it by adding a READ_ONCE() in
percpu_counter_read_positive() which could also service as the existing
compiler memory barrier.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/1582302724-2804-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Alexander Potapenko
505a0ef15f kasan: stackdepot: move filter_irq_stacks() to stackdepot.c
filter_irq_stacks() can be used by other tools (e.g.  KMSAN), so it needs
to be moved to a common location.  lib/stackdepot.c seems a good place, as
filter_irq_stacks() is usually applied to the output of
stack_trace_save().

This patch has been previously mailed as part of KMSAN RFC patch series.

[glider@google.co: nds32: linker script: add SOFTIRQENTRY_TEXT\
  Link: http://lkml.kernel.org/r/20200311121002.241430-1-glider@google.com
[glider@google.com: add IRQENTRY_TEXT and SOFTIRQENTRY_TEXT to linker script]
  Link: http://lkml.kernel.org/r/20200311121124.243352-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Link: http://lkml.kernel.org/r/20200220141916.55455-3-glider@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Alexander Potapenko
7b65942fb2 lib/stackdepot.c: build with -fno-builtin
Clang may replace stackdepot_memcmp() with a call to instrumented bcmp(),
which is exactly what we wanted to avoid creating stackdepot_memcmp().
Building the file with -fno-builtin prevents such optimizations.

This patch has been previously mailed as part of KMSAN RFC patch series.

Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Link: http://lkml.kernel.org/r/20200220141916.55455-2-glider@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Alexander Potapenko
69866e156c lib/stackdepot.c: check depot_index before accessing the stack slab
Avoid crashes on corrupted stack ids.  Despite stack ID corruption may
indicate other bugs in the program, we'd better fail gracefully on such
IDs instead of crashing the kernel.

This patch has been previously mailed as part of KMSAN RFC patch series.

Link: http://lkml.kernel.org/r/20200220141916.55455-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: lib/stackdepot.c: fix a condition in stack_depot_fetch()

We should check for a NULL pointer first before adding the offset.
Otherwise if the pointer is NULL and the offset is non-zero, it will lead
to an Oops.

Fixes: d45048e65a59 ("lib/stackdepot.c: check depot_index before accessing the stack slab")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Alexander Potapenko <glider@google.com>
Link: http://lkml.kernel.org/r/20200312113006.GA20562@mwanda
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Kees Cook
9cf016e6b4 lib: test_stackinit.c: XFAIL switch variable init tests
The tests for initializing a variable defined between a switch statement's
test and its first "case" statement are currently not initialized in
Clang[1] nor the proposed auto-initialization feature in GCC.

We should retain the test (so that we can evaluate compiler fixes), but
mark it as an "expected fail".  The rest of the kernel source will be
adjusted to avoid this corner case.

Also disable -Wswitch-unreachable for the test so that the intentionally
broken code won't trigger warnings for GCC (nor future Clang) when
initialization happens this unhandled place.

[1] https://bugs.llvm.org/show_bug.cgi?id=44916

Suggested-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jann Horn <jannh@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Link: http://lkml.kernel.org/r/202002191358.2897A07C6@keescook
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Geert Uytterhoeven
6e85318521 lib/scatterlist: fix sg_copy_buffer() kerneldoc
Add the missing closing parenthesis to the description for the to_buffer
parameter of sg_copy_buffer().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com
Link: http://lkml.kernel.org/r/20200212084241.8778-1-geert+renesas@glider.be
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Gustavo A. R. Silva
51022f8715 lib/ts_kmp.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205948.GA26459@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Gustavo A. R. Silva
842ae1f52b lib/ts_fsm.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205813.GA25602@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:43 -07:00
Gustavo A. R. Silva
c6e2ac3b47 lib/ts_bm.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205620.GA24694@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Gustavo A. R. Silva
a44ce51370 lib/bch.c: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Konstantin Khlebnikov
aecd42df6d lib/test_lockup.c: add parameters for locking generic vfs locks
file_path=<path>	defines file or directory to open
lock_inode=Y		set lock_rwsem_ptr to inode->i_rwsem
lock_mapping=Y		set lock_rwsem_ptr to mapping->i_mmap_rwsem
lock_sb_umount=Y	set lock_rwsem_ptr to sb->s_umount

This gives safe and simple way to see how system reacts to contention of
common vfs locks and how syscalls depend on them directly or indirectly.

For example to block s_umount for 60 seconds:
# modprobe test_lockup file_path=. lock_sb_umount time_secs=60 state=S

This is useful for checking/testing scalability issues like this:
https://lore.kernel.org/lkml/158497590858.7371.9311902565121473436.stgit@buzz/

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Colin Ian King
ad3f434b87 lib/test_lockup.c: fix spelling mistake "iteraions" -> "iterations"
There is a spelling mistake in a pr_notice message.  Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20200221155145.79522-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00
Konstantin Khlebnikov
30428ef5d1 lib/test_lockup: test module to generate lockups
CONFIG_TEST_LOCKUP=m adds module "test_lockup" that helps to make sure
that watchdogs and lockup detectors are working properly.

Depending on module parameters test_lockup could emulate soft or hard
lockup, "hung task", hold arbitrary lock, allocate bunch of pages.

Also it could generate series of lockups with cooling-down periods, in
this way it could be used as "ping" for locks or page allocator.  Loop
checks signals between iteration thus could be stopped by ^C.

# modinfo test_lockup
...
parm:           time_secs:lockup time in seconds, default 0 (uint)
parm:           time_nsecs:nanoseconds part of lockup time, default 0 (uint)
parm:           cooldown_secs:cooldown time between iterations in seconds, default 0 (uint)
parm:           cooldown_nsecs:nanoseconds part of cooldown, default 0 (uint)
parm:           iterations:lockup iterations, default 1 (uint)
parm:           all_cpus:trigger lockup at all cpus at once (bool)
parm:           state:wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state (charp)
parm:           use_hrtimer:use high-resolution timer for sleeping (bool)
parm:           iowait:account sleep time as iowait (bool)
parm:           lock_read:lock read-write locks for read (bool)
parm:           lock_single:acquire locks only at one cpu (bool)
parm:           reacquire_locks:release and reacquire locks/irq/preempt between iterations (bool)
parm:           touch_softlockup:touch soft-lockup watchdog between iterations (bool)
parm:           touch_hardlockup:touch hard-lockup watchdog between iterations (bool)
parm:           call_cond_resched:call cond_resched() between iterations (bool)
parm:           measure_lock_wait:measure lock wait time (bool)
parm:           lock_wait_threshold:print lock wait time longer than this in nanoseconds, default off (ulong)
parm:           disable_irq:disable interrupts: generate hard-lockups (bool)
parm:           disable_softirq:disable bottom-half irq handlers (bool)
parm:           disable_preempt:disable preemption: generate soft-lockups (bool)
parm:           lock_rcu:grab rcu_read_lock: generate rcu stalls (bool)
parm:           lock_mmap_sem:lock mm->mmap_sem: block procfs interfaces (bool)
parm:           lock_rwsem_ptr:lock rw_semaphore at address (ulong)
parm:           lock_mutex_ptr:lock mutex at address (ulong)
parm:           lock_spinlock_ptr:lock spinlock at address (ulong)
parm:           lock_rwlock_ptr:lock rwlock at address (ulong)
parm:           alloc_pages_nr:allocate and free pages under locks (uint)
parm:           alloc_pages_order:page order to allocate (uint)
parm:           alloc_pages_gfp:allocate pages with this gfp_mask, default GFP_KERNEL (uint)
parm:           alloc_pages_atomic:allocate pages with GFP_ATOMIC (bool)
parm:           reallocate_pages:free and allocate pages between iterations (bool)

Parameters for locking by address are unsafe and taints kernel. With
CONFIG_DEBUG_SPINLOCK=y they at least check magics for embedded spinlocks.

Examples:

task hang in D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D

task hang in io-wait D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D iowait

softlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R

hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R disable_irq

system-wide hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq all_cpus

rcu stall:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 lock_rcu touch_softlockup

lock mmap_sem / block procfs interfaces:
modprobe test_lockup time_secs=1 iterations=60 state=S lock_mmap_sem

lock tasklist_lock for read / block forks:
TASKLIST_LOCK=$(awk '$3 == "tasklist_lock" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq lock_read lock_rwlock_ptr=$TASKLIST_LOCK

lock namespace_sem / block vfs mount operations:
NAMESPACE_SEM=$(awk '$3 == "namespace_sem" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_rwsem_ptr=$NAMESPACE_SEM

lock cgroup mutex / block cgroup operations:
CGROUP_MUTEX=$(awk '$3 == "cgroup_mutex" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX

ping cgroup_mutex every second and measure maximum lock wait time:
modprobe test_lockup cooldown_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX reacquire_locks measure_lock_wait

[linux@roeck-us.net: rename disable_irq to fix build error]
  Link: http://lkml.kernel.org/r/20200317133614.23152-1-linux@roeck-us.net
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/158132859146.2797.525923171323227836.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:42 -07:00