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2020-04-07checkpatch: check proper licensing of Devicetree bindingsLubomir Rintel
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>
2020-04-07checkpatch: improve Gerrit Change-Id: testJoe Perches
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>
2020-04-07checkpatch: add command-line option for TAB sizeAntonio Borneo
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>
2020-04-07checkpatch: fix multiple const * typesAntonio Borneo
Commit 1574a29f8e76 ("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: 1574a29f8e76 ("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>
2020-04-07checkpatch: fix minor typo and mixed space+tab in indentationAntonio Borneo
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>
2020-04-07checkpatch: prefer fallthrough; over fallthrough commentsJoe Perches
commit 294f69e662d1 ("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>
2020-04-07checkpatch: support "base-commit:" formatJohn Hubbard
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>
2020-04-07checkpatch: check SPDX tags in YAML filesLubomir Rintel
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>
2020-04-07checkpatch: remove email address comment from email address comparisonsJoe Perches
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>
2020-04-07lib/dynamic_debug.c: use address-of operator on section symbolsNathan Chancellor
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>
2020-04-07linux/bits.h: add compile time sanity check of GENMASK inputsRikard Falkeborn
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 aa4c0c9091b0 ("net: stmmac: Fix misuses of GENMASK macro") and commit 9bdd7bb3a844 ("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 95b980d62d52 ("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>
2020-04-07lib/test_kmod.c: remove a NULL testDan Carpenter
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>
2020-04-07lib/rbtree: fix coding style of assignmentschenqiwu
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>
2020-04-07lib/test_bitmap.c: make use of EXP2_IN_BITSAndy Shevchenko
Commit 30544ed5de43 ("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>
2020-04-07percpu_counter: fix a data race at vm_committed_asQian Cai
"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>
2020-04-07kasan: stackdepot: move filter_irq_stacks() to stackdepot.cAlexander Potapenko
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>
2020-04-07lib/stackdepot.c: build with -fno-builtinAlexander Potapenko
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>
2020-04-07lib/stackdepot.c: check depot_index before accessing the stack slabAlexander Potapenko
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>
2020-04-07lib: test_stackinit.c: XFAIL switch variable init testsKees Cook
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>
2020-04-07lib/scatterlist: fix sg_copy_buffer() kerneldocGeert Uytterhoeven
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>
2020-04-07lib/ts_kmp.c: replace zero-length array with flexible-array memberGustavo A. R. Silva
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 76497732932f ("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>
2020-04-07lib/ts_fsm.c: replace zero-length array with flexible-array memberGustavo A. R. Silva
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 76497732932f ("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>
2020-04-07lib/ts_bm.c: replace zero-length array with flexible-array memberGustavo A. R. Silva
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 76497732932f ("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>
2020-04-07lib/bch.c: replace zero-length array with flexible-array memberGustavo A. R. Silva
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 76497732932f ("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>
2020-04-07lib/test_lockup.c: add parameters for locking generic vfs locksKonstantin Khlebnikov
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>
2020-04-07lib/test_lockup.c: fix spelling mistake "iteraions" -> "iterations"Colin Ian King
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>
2020-04-07lib/test_lockup: test module to generate lockupsKonstantin Khlebnikov
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>
2020-04-07bitops: always inline sign extension helpersJosh Poimboeuf
With CONFIG_CC_OPTIMIZE_FOR_SIZE, objtool reports: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x5b7: call to gen8_canonical_addr() with UACCESS enabled This means i915_gem_execbuffer2_ioctl() is calling gen8_canonical_addr() from the user_access_begin/end critical region (i.e, with SMAP disabled). While it's probably harmless in this case, in general we like to avoid extra function calls in SMAP-disabled regions because it can open up inadvertent security holes. Fix the warning by changing the sign extension helpers to __always_inline. This convinces GCC to inline gen8_canonical_addr(). The sign extension functions are trivial anyway, so it makes sense to always inline them. With my test optimize-for-size-based config, this actually shrinks the text size of i915_gem_execbuffer.o by 45 bytes -- and no change for vmlinux. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07MAINTAINERS: list the section entries in the preferred orderJoe Perches
The MAINTAINERS file header has never shown a preferred order for the section entries but scripts/parse-maintainers.pl added a preferred order with commit 61f741645a35 ("parse-maintainers: Add section pattern sorting") Commit 5cdbec108fd2 ("parse-maintainers: Do not sort section content by default") changed the preferred order to be a bit more sensible. Update the MAINTAINERS section description block to use this preferred section entry ordering. Add a slightly better description for the N: entry too. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: http://lkml.kernel.org/r/5aa5aad6fb1678230c260337dc066cd449a2bf32.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07compiler.h: fix error in BUILD_BUG_ON() reportingVegard Nossum
compiletime_assert() uses __LINE__ to create a unique function name. This means that if you have more than one BUILD_BUG_ON() in the same source line (which can happen if they appear e.g. in a macro), then the error message from the compiler might output the wrong condition. For this source file: #include <linux/build_bug.h> #define macro() \ BUILD_BUG_ON(1); \ BUILD_BUG_ON(0); void foo() { macro(); } gcc would output: ./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_9' declared with attribute error: BUILD_BUG_ON failed: 0 _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) However, it was not the BUILD_BUG_ON(0) that failed, so it should say 1 instead of 0. With this patch, we use __COUNTER__ instead of __LINE__, so each BUILD_BUG_ON() gets a different function name and the correct condition is printed: ./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_0' declared with attribute error: BUILD_BUG_ON failed: 1 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Daniel Santos <daniel.santos@pobox.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Ian Abbott <abbotti@mev.co.uk> Cc: Joe Perches <joe@perches.com> Link: http://lkml.kernel.org/r/20200331112637.25047-1-vegard.nossum@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07compiler: remove CONFIG_OPTIMIZE_INLINING entirelyMasahiro Yamada
Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") made this always-on option. We released v5.4 and v5.5 including that commit. Remove the CONFIG option and clean up the code now. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: David Miller <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200220110807.32534-2-masahiroy@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLININGMasahiro Yamada
The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected because <linux/compiler_types.h> is parsed before vclock_gettime.c since 28128c61e08e ("kconfig.h: Include compiler types to avoid missed struct attributes"). Since then, <linux/compiler_types.h> is included really early by using the '-include' option. So, you cannot negate the decision of <linux/compiler_types.h> in this way. You can confirm it by checking the pre-processed code, like this: $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE. It is about two years since 28128c61e08e. Nobody has reported a problem (or, nobody has even noticed the fact that this code is not working). It is ugly and unreliable to attempt to undefine a CONFIG option from C files, and anyway the inlining heuristic is up to the compiler. Just remove the broken code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: David Miller <davem@davemloft.net> Link: http://lkml.kernel.org/r/20200220110807.32534-1-masahiroy@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07kernel/extable.c: use address-of operator on section symbolsNathan Chancellor
Clang warns: ../kernel/extable.c:37:52: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) { ^ 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> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: https://github.com/ClangBuiltLinux/linux/issues/892 Link: http://lkml.kernel.org/r/20200219202036.45702-1-natechancellor@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07asm-generic: fix unistd_32.h generation formatMichal Simek
Generated files are also checked by sparse that's why add newline to remove sparse (C=1) warning. The issue was found on Microblaze and reported like this: ./arch/microblaze/include/generated/uapi/asm/unistd_32.h:438:45: warning: no newline at end of file Mips and PowerPC have it already but let's align with style used by m68k. Signed-off-by: Michal Simek <michal.simek@xilinx.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Stefan Asserhall <stefan.asserhall@xilinx.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> (xtensa) Cc: Arnd Bergmann <arnd@arndb.de> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Zankel <chris@zankel.net> Cc: David S. Miller <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Helge Deller <deller@gmx.de> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Burton <paulburton@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Tony Luck <tony.luck@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/4d32ab4e1fb2edb691d2e1687e8fb303c09fd023.1581504803.git.michal.simek@xilinx.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: inline m_next_vma into m_nextMatthew Wilcox (Oracle)
It's clearer to just put this inline. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200317193201.9924-5-adobriyan@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07seq_file: remove m->versionMatthew Wilcox (Oracle)
The process maps file was the only user of version (introduced back in 2005). Now that it uses ppos instead, we can remove it. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200317193201.9924-4-adobriyan@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: use ppos instead of m->versionMatthew Wilcox (Oracle)
The ppos is a private cursor, just like m->version. Use the canonical cursor, not a special one. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200317193201.9924-3-adobriyan@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: remove m_cache_vmaMatthew Wilcox (Oracle)
Instead of setting m->version in the show method, set it in m_next(), where it should be. Also remove the fallback code for failing to find a vma, or version being zero. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200317193201.9924-2-adobriyan@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: inline vma_stop into m_stopMatthew Wilcox (Oracle)
Instead of calling vma_stop() from m_start() and m_next(), do its work in m_stop(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200317193201.9924-1-adobriyan@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: speed up /proc/*/statmAlexey Dobriyan
top(1) reads all /proc/*/statm files but kernel threads will always have zeros. Print those zeroes directly without going through seq_put_decimal_ull(). Speed up reading /proc/2/statm (which is kthreadd) is like 3%. My system has more kernel threads than normal processes after booting KDE. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200307154435.GA2788@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07proc: faster open/read/close with "permanent" filesAlexey Dobriyan
Now that "struct proc_ops" exist we can start putting there stuff which could not fly with VFS "struct file_operations"... Most of fs/proc/inode.c file is dedicated to make open/read/.../close reliable in the event of disappearing /proc entries which usually happens if module is getting removed. Files like /proc/cpuinfo which never disappear simply do not need such protection. Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such "permanent" files. Enable "permanent" flag for /proc/cpuinfo /proc/kmsg /proc/modules /proc/slabinfo /proc/stat /proc/sysvipc/* /proc/swaps More will come once I figure out foolproof way to prevent out module authors from marking their stuff "permanent" for performance reasons when it is not. This should help with scalability: benchmark is "read /proc/cpuinfo R times by N threads scattered over the system". N R t, s (before) t, s (after) ----------------------------------------------------- 64 4096 1.582458 1.530502 -3.2% 256 4096 6.371926 6.125168 -3.9% 1024 4096 25.64888 24.47528 -4.6% Benchmark source: #include <chrono> #include <iostream> #include <thread> #include <vector> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN); int N; const char *filename; int R; int xxx = 0; int glue(int n) { cpu_set_t m; CPU_ZERO(&m); CPU_SET(n, &m); return sched_setaffinity(0, sizeof(cpu_set_t), &m); } void f(int n) { glue(n % NR_CPUS); while (*(volatile int *)&xxx == 0) { } for (int i = 0; i < R; i++) { int fd = open(filename, O_RDONLY); char buf[4096]; ssize_t rv = read(fd, buf, sizeof(buf)); asm volatile ("" :: "g" (rv)); close(fd); } } int main(int argc, char *argv[]) { if (argc < 4) { std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R "; return 1; } N = atoi(argv[1]); filename = argv[2]; R = atoi(argv[3]); for (int i = 0; i < NR_CPUS; i++) { if (glue(i) == 0) break; } std::vector<std::thread> T; T.reserve(N); for (int i = 0; i < N; i++) { T.emplace_back(f, i); } auto t0 = std::chrono::system_clock::now(); { *(volatile int *)&xxx = 1; for (auto& t: T) { t.join(); } } auto t1 = std::chrono::system_clock::now(); std::chrono::duration<double> dt = t1 - t0; std::cout << dt.count() << ' '; return 0; } P.S.: Explicit randomization marker is added because adding non-function pointer will silently disable structure layout randomization. [akpm@linux-foundation.org: coding style fixes] Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Joe Perches <joe@perches.com> Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07fs/proc/inode.c: annotate close_pdeo() for sparseJules Irenge
Fix sparse locking imbalance warning: warning: context imbalance in close_pdeo() - unexpected unlock Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200227201538.GA30462@avx2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: remove dummy struct bootmem_data/bootmem_data_tWaiman Long
Both bootmem_data and bootmem_data_t structures are no longer defined. Remove the dummy forward declarations. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Baoquan He <bhe@redhat.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Link: http://lkml.kernel.org/r/20200326022617.26208-1-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/dmapool.c: micro-optimisation remove unnecessary branchMateusz Nosek
Previously there was a check if 'size' is aligned to 'align' and if not then it was aligned. This check was expensive as both branch and division are expensive instructions in most architectures. 'ALIGN' function on already aligned value will not change it, and as it is cheaper than branch + division it can be executed all the time and branch can be removed. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07include/linux/memremap.h: remove stale commentsIra Weiny
Fixes: 80a72d0af05a ("memremap: remove the data field in struct dev_pagemap") Fixes: fdc029b19dfd ("memremap: remove the dev field in struct dev_pagemap") Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/20200316213205.145333-1-ira.weiny@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07include/linux/swapops.h: correct guards for non_swap_entry()Steven Price
If CONFIG_DEVICE_PRIVATE is defined, but neither CONFIG_MEMORY_FAILURE nor CONFIG_MIGRATION, then non_swap_entry() will return 0, meaning that the condition (non_swap_entry(entry) && is_device_private_entry(entry)) in zap_pte_range() will never be true even if the entry is a device private one. Equally any other code depending on non_swap_entry() will not function as expected. I originally spotted this just by looking at the code, I haven't actually observed any problems. Looking a bit more closely it appears that actually this situation (currently at least) cannot occur: DEVICE_PRIVATE depends on ZONE_DEVICE ZONE_DEVICE depends on MEMORY_HOTREMOVE MEMORY_HOTREMOVE depends on MIGRATION Fixes: 5042db43cc26 ("mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory") Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: John Hubbard <jhubbard@nvidia.com> Link: http://lkml.kernel.org/r/20200305130550.22693-1-steven.price@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: use fallthrough;Joe Perches
Convert the various /* fallthrough */ comments to the pseudo-keyword fallthrough; Done via script: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Link: http://lkml.kernel.org/r/f62fea5d10eb0ccfc05d87c242a620c261219b66.camel@perches.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/mm_init.c: clean code. Use BUILD_BUG_ON when comparing compile time constantMateusz Nosek
MAX_ZONELISTS is a compile time constant, so it should be compared using BUILD_BUG_ON not BUG_ON. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Link: http://lkml.kernel.org/r/20200228224617.11343-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm: fix ambiguous comments for better code readabilitychenqiwu
The parameter of remap_pfn_range() @pfn passed from the caller is actually a page-frame number converted by corresponding physical address of kernel memory, the original comment is ambiguous that may mislead the users. Meanwhile, there is an ambiguous typo "VMM" in the comment of vm_area_struct. So fixing them will make the code more readable. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1583026921-15279-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07mm/zsmalloc: add missing annotation for unpin_tag()Jules Irenge
Sparse reports a warning at unpin_tag()() warning: context imbalance in unpin_tag() - unexpected unlock The root cause is the missing annotation at unpin_tag() Add the missing __releases(bitlock) annotation Signed-off-by: Jules Irenge <jbi.octave@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Minchan Kim <minchan@kernel.org> Link: http://lkml.kernel.org/r/20200214204741.94112-14-jbi.octave@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>