- 07 Apr, 2020 40 commits
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Gustavo A. R. Silva authored
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 76497732 ("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@embeddedorSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by:Peter Oberparleiter <oberpar@linux.ibm.com> Link: http://lkml.kernel.org/r/20200213152241.GA877@embeddedorSigned-off-by:
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Qiujun Huang authored
There is a typo in comment. Fix it. s/assuems/assumes/ Signed-off-by:
Qiujun Huang <hqjagain@gmail.com> Signed-off-by:
Luis Chamberlain <mcgrof@kernel.org> Link: http://lkml.kernel.org/r/1585891029-6450-1-git-send-email-hqjagain@gmail.comSigned-off-by:
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Colin Ian King authored
There are several places where code is indented incorrectly. Fix these. Signed-off-by:
Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Will Deacon authored
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:
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.orgSigned-off-by:
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Will Deacon authored
The 'data_breakpoint' test code is the only modular user of kallsyms_lookup_name(), which was exported as part of fixing the test in f60d24d2 ("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:
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Will Deacon authored
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: -
Alexey Dobriyan authored
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:
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Alexey Dobriyan authored
PT_INTERP ELF header can be spared if executable is static. Signed-off-by:
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Alexey Dobriyan authored
"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:
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Jason Baron authored
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:
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Roman Penyaev authored
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:
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Joe Perches authored
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:
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Lubomir Rintel authored
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:
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.skSigned-off-by:
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Joe Perches authored
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:
John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/2f6d5f8766fe7439a116c77ea8cc721a3f2d77a2.camel@perches.comSigned-off-by:
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Antonio Borneo authored
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#styleformatSigned-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:
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Antonio Borneo authored
Commit 1574a29f ("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: 1574a29f ("checkpatch: allow multiple const * types") Signed-off-by:
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Antonio Borneo authored
Fix spelling of "concatenation". Don't use tab after space in indentation. Signed-off-by:
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Joe Perches authored
commit 294f69e6 ("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:
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John Hubbard authored
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:John Hubbard <jhubbard@nvidia.com> Signed-off-by:
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Lubomir Rintel authored
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:
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Joe Perches authored
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:
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Nathan Chancellor authored
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:
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Rikard Falkeborn authored
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 aa4c0c90 ("net: stmmac: Fix misuses of GENMASK macro") and commit 9bdd7bb3 ("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 95b980d6 ("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=19449Signed-off-by:
Rikard Falkeborn <rikard.falkeborn@gmail.com> Signed-off-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.comSigned-off-by:
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Dan Carpenter authored
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:
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chenqiwu authored
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:
Michel Lespinasse <walken@google.com> Link: http://lkml.kernel.org/r/1582621140-25850-1-git-send-email-qiwuchen55@gmail.comSigned-off-by:
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Andy Shevchenko authored
Commit 30544ed5 ("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:
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Qian Cai authored
"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:
Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/1582302724-2804-1-git-send-email-cai@lca.pwSigned-off-by:
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Alexander Potapenko authored
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.comSigned-off-by:
Alexander Potapenko <glider@google.com> Signed-off-by:
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Alexander Potapenko authored
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:
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Alexander Potapenko authored
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.comSigned-off-by:
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Kees Cook authored
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=44916Suggested-by:
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Geert Uytterhoeven authored
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:
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Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Gustavo A. R. Silva authored
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 76497732 ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: -
Konstantin Khlebnikov authored
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:
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Colin Ian King authored
There is a spelling mistake in a pr_notice message. Fix it. Signed-off-by:
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