- 18 Nov, 2017 40 commits
-
-
Jason Baron authored
The use of ep_call_nested() in ep_eventpoll_poll(), which is the .poll routine for an epoll fd, is used to prevent excessively deep epoll nesting, and to prevent circular paths. However, we are already preventing these conditions during EPOLL_CTL_ADD. In terms of too deep epoll chains, we do in fact allow deep nesting of the epoll fds themselves (deeper than EP_MAX_NESTS), however we don't allow more than EP_MAX_NESTS when an epoll file descriptor is actually connected to a wakeup source. Thus, we do not require the use of ep_call_nested(), since ep_eventpoll_poll(), which is called via ep_scan_ready_list() only continues nesting if there are events available. Since ep_call_nested() is implemented using a global lock, applications that make use of nested epoll can see large performance improvements with this change. Davidlohr said: : Improvements are quite obscene actually, such as for the following : epoll_wait() benchmark with 2 level nesting on a 80 core IvyBridge: : : ncpus vanilla dirty delta : 1 2447092 3028315 +23.75% : 4 231265 2986954 +1191.57% : 8 121631 2898796 +2283.27% : 16 59749 2902056 +4757.07% : 32 26837 2326314 +8568.30% : 64 12926 1341281 +10276.61% : : (http://linux-scalability.org/epoll/epoll-test.c) Link: http://lkml.kernel.org/r/1509430214-5599-1-git-send-email-jbaron@akamai.comSigned-off-by:
Jason Baron <jbaron@akamai.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Salman Qazi <sqazi@google.com> Cc: Hou Tao <houtao1@huawei.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Jason Baron authored
ep_poll_safewake() is used to wakeup potentially nested epoll file descriptors. The function uses ep_call_nested() to prevent entering the same wake up queue more than once, and to prevent excessively deep wakeup paths (deeper than EP_MAX_NESTS). However, this is not necessary since we are already preventing these conditions during EPOLL_CTL_ADD. This saves extra function calls, and avoids taking a global lock during the ep_call_nested() calls. I have, however, left ep_call_nested() for the CONFIG_DEBUG_LOCK_ALLOC case, since ep_call_nested() keeps track of the nesting level, and this is required by the call to spin_lock_irqsave_nested(). It would be nice to remove the ep_call_nested() calls for the CONFIG_DEBUG_LOCK_ALLOC case as well, however its not clear how to simply pass the nesting level through multiple wake_up() levels without more surgery. In any case, I don't think CONFIG_DEBUG_LOCK_ALLOC is generally used for production. This patch, also apparently fixes a workload at Google that Salman Qazi reported by completely removing the poll_safewake_ncalls->lock from wakeup paths. Link: http://lkml.kernel.org/r/1507920533-8812-1-git-send-email-jbaron@akamai.comSigned-off-by:
Davidlohr Bueso <dbueso@suse.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Salman Qazi <sqazi@google.com> Signed-off-by:
-
Shakeel Butt authored
A userspace application can directly trigger the allocations from eventpoll_epi and eventpoll_pwq slabs. A buggy or malicious application can consume a significant amount of system memory by triggering such allocations. Indeed we have seen in production where a buggy application was leaking the epoll references and causing a burst of eventpoll_epi and eventpoll_pwq slab allocations. This patch opt-in the charging of eventpoll_epi and eventpoll_pwq slabs. There is a per-user limit (~4% of total memory if no highmem) on these caches. I think it is too generous particularly in the scenario where jobs of multiple users are running on the system and the administrator is reducing cost by overcomitting the memory. This is unaccounted kernel memory and will not be considered by the oom-killer. I think by accounting it to kmemcg, for systems with kmem accounting enabled, we can provide better isolation between jobs of different users. Link: http://lkml.kernel.org/r/20171003021519.23907-1-shakeelb@google.comSigned-off-by:
Shakeel Butt <shakeelb@google.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Greg Thelen <gthelen@google.com> Signed-off-by:
-
Masahiro Yamada authored
checkpatch.pl does not check missing blank line before module_*_driver. I want it to behave likewise for builtin_*_driver. Link: http://lkml.kernel.org/r/1505700081-12854-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by:
Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by:
Joe Perches <joe@perches.com> Signed-off-by:
-
Joe Perches authored
Lines that end in an open bracket or open parenthesis are generally hard to follow. Lines following those ending with open parenthesis are also rarely aligned to that open parenthesis. Suggest not ending lines with '[' or '(' Link: http://lkml.kernel.org/r/8fd0b2b4a7482064254e37931eb9302a81d5aa2f.1508340786.git.joe@perches.comSigned-off-by:Vivien Didelot <vivien.didelot@savoirfairelinux.com> Signed-off-by:
-
Joe Perches authored
So the line length check can be bypassed by its callers. Link: http://lkml.kernel.org/r/7de542c08a6e79f2ebe7c1416c9f403c23fdcc09.1508282823.git.joe@perches.comSigned-off-by:
Song Liu <songliubraving@fb.com> Tested-by:
-
Joe Perches authored
Some of the definitions are very long and can't be split into multiple lines because ctags is limited. Exempt these lines from the line length checks. See commit 25528213 ("tags: Fix DEFINE_PER_CPU expansions") for more details. Link: http://lkml.kernel.org/r/1508170320.6530.15.camel@perches.comSigned-off-by:
Mark Rutland <mark.rutland@arm.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by:
-
Joe Perches authored
There was code in checkpatch that allowed continuation printks to be used without KERN_CONT. Remove the continuation check and always require a KERN_<LEVEL>. Link: http://lkml.kernel.org/r/61980ef41d5b9b6543da1c49055042e0ab74d308.1507047008.git.joe@perches.comSigned-off-by:
-
Heinrich Schuchardt authored
void foo(int a) switch (a) { case 'h': fun1(); exit(1); default: } creates a warning "Possible switch case/default not preceded by break or fallthrough comment". exit( should be treated like return. Link: http://lkml.kernel.org/r/20170910154618.25819-1-xypron.glpk@gmx.deSigned-off-by:Heinrich Schuchardt <xypron.glpk@gmx.de> Acked-by:
-
Miles Chen authored
Current unnamed function definition argument does not include function pointer cases and it reports something like: WARNING: function definition argument 'void' should also have an identifier name +unsigned int (*dummy)(void); Support function pointers for unnamed function arguments Link: http://lkml.kernel.org/r/1505389925-31087-1-git-send-email-miles.chen@mediatek.comSigned-off-by:
Miles Chen <miles.chen@mediatek.com> Acked-by:
-
Yury Norov authored
find_bit functions are widely used in the kernel, including hot paths. This module tests performance of those functions in 2 typical scenarios: randomly filled bitmap with relatively equal distribution of set and cleared bits, and sparse bitmap which has 1 set bit for 500 cleared bits. On ThunderX machine: Start testing find_bit() with random-filled bitmap find_next_bit: 240043 cycles, 164062 iterations find_next_zero_bit: 312848 cycles, 163619 iterations find_last_bit: 193748 cycles, 164062 iterations find_first_bit: 177720874 cycles, 164062 iterations Start testing find_bit() with sparse bitmap find_next_bit: 3633 cycles, 656 iterations find_next_zero_bit: 620399 cycles, 327025 iterations find_last_bit: 3038 cycles, 656 iterations find_first_bit: 691407 cycles, 656 iterations [arnd@arndb.de: use correct format string for find-bit tests] Link: http://lkml.kernel.org/r/20171113135605.3166307-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20171109140714.13168-1-ynorov@caviumnetworks.comSigned-off-by:
Yury Norov <ynorov@caviumnetworks.com> Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Reviewed-by:
Clement Courbet <courbet@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
-
Davidlohr Bueso authored
Fengguang reported soft lockups while running the rbtree and interval tree test modules. The logic for these tests all occur in init phase, and we currently are pounding with the default values for number of nodes and number of iterations of each test. Reduce the latter by two orders of magnitude. This does not influence the value of the tests in that one thousand times by default is enough to get the picture. Link: http://lkml.kernel.org/r/20171109161715.xai2dtwqw2frhkcm@linux-n805Signed-off-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
-
Cheng Jian authored
The uniform structure filter_arg sets its union based on the difference of enum filter_arg_type, However, some functions use implicit type conversion obviously. warning: implicit conversion from enumeration type 'enum filter_exp_type' to different enumeration type 'enum filter_op_type' warning: implicit conversion from enumeration type 'enum filter_cmp_type' to different enumeration type 'enum filter_exp_type' Link: http://lkml.kernel.org/r/1509938415-113825-1-git-send-email-cj.chengjian@huawei.comSigned-off-by:
Cheng Jian <cj.chengjian@huawei.com> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Xie XiuQi <xiexiuqi@huawei.com> Cc: Li Bin <huawei.libin@huawei.com> Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org> Signed-off-by:
-
Liu, Changcheng authored
Don't leak idle function address in NMI backtrace. Link: http://lkml.kernel.org/r/20171106165648.GA95243@sofiaSigned-off-by:
Liu Changcheng <changcheng.liu@intel.com> Reviewed-by:
Petr Mladek <pmladek@suse.com> Reviewed-by:
Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by:
-
Stephen Bates authored
If the amount of resources allocated to a gen_pool exceeds 2^32 then the avail atomic overflows and this causes problems when clients try and borrow resources from the pool. This is only expected to be an issue on 64 bit systems. Add the <linux/atomic.h> header to pull in atomic_long* operations. So that 32 bit systems continue to use atomic32_t but 64 bit systems can use atomic64_t. Link: http://lkml.kernel.org/r/1509033843-25667-1-git-send-email-sbates@raithlin.comSigned-off-by:
Stephen Bates <sbates@raithlin.com> Reviewed-by:
Logan Gunthorpe <logang@deltatee.com> Reviewed-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by:
Daniel Mentz <danielmentz@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
-
Peter Zijlstra authored
Our current int_sqrt() is not rough nor any approximation; it calculates the exact value of: floor(sqrt()). Document this. Link: http://lkml.kernel.org/r/20171020164645.001652117@infradead.orgSigned-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
-
Peter Zijlstra authored
The initial value (@M) compute is: m = 1UL << (BITS_PER_LONG - 2); while (m > x) m >>= 2; Which is a linear search for the highest even bit smaller or equal to @x We can implement this using a binary search using __fls() (or better when its hardware implemented). m = 1UL << (__fls(x) & ~1UL); Especially for small values of @x; which are the more common arguments when doing a CDF on idle times; the linear search is near to worst case, while the binary search of __fls() is a constant 6 (or 5 on 32bit) branches. cycles: branches: branch-misses: PRE: hot: 43.633557 +- 0.034373 45.333132 +- 0.002277 0.023529 +- 0.000681 cold: 207.438411 +- 0.125840 45.333132 +- 0.002277 6.976486 +- 0.004219 SOFTWARE FLS: hot: 29.576176 +- 0.028850 26.666730 +- 0.004511 0.019463 +- 0.000663 cold: 165.947136 +- 0.188406 26.666746 +- 0.004511 6.133897 +- 0.004386 HARDWARE FLS: hot: 24.720922 +- 0.025161 20.666784 +- 0.004509 0.020836 +- 0.000677 cold: 132.777197 +- 0.127471 20.666776 +- 0.004509 5.080285 +- 0.003874 Averages computed over all values <128k using a LFSR to generate order. Cold numbers have a LFSR based branch trace buffer 'confuser' ran between each int_sqrt() invocation. Link: http://lkml.kernel.org/r/20171020164644.936577234@infradead.orgSigned-off-by:
Will Deacon <will.deacon@arm.com> Acked-by:
-
Peter Zijlstra authored
The current int_sqrt() computation is sub-optimal for the case of small @x. Which is the interesting case when we're going to do cumulative distribution functions on idle times, which we assume to be a random variable, where the target residency of the deepest idle state gives an upper bound on the variable (5e6ns on recent Intel chips). In the case of small @x, the compute loop: while (m != 0) { b = y + m; y >>= 1; if (x >= b) { x -= b; y += m; } m >>= 2; } can be reduced to: while (m > x) m >>= 2; Because y==0, b==m and until x>=m y will remain 0. And while this is computationally equivalent, it runs much faster because there's less code, in particular less branches. cycles: branches: branch-misses: OLD: hot: 45.109444 +- 0.044117 44.333392 +- 0.002254 0.018723 +- 0.000593 cold: 187.737379 +- 0.156678 44.333407 +- 0.002254 6.272844 +- 0.004305 PRE: hot: 67.937492 +- 0.064124 66.999535 +- 0.000488 0.066720 +- 0.001113 cold: 232.004379 +- 0.332811 66.999527 +- 0.000488 6.914634 +- 0.006568 POST: hot: 43.633557 +- 0.034373 45.333132 +- 0.002277 0.023529 +- 0.000681 cold: 207.438411 +- 0.125840 45.333132 +- 0.002277 6.976486 +- 0.004219 Averages computed over all values <128k using a LFSR to generate order. Cold numbers have a LFSR based branch trace buffer 'confuser' ran between each int_sqrt() invocation. Link: http://lkml.kernel.org/r/20171020164644.876503355@infradead.org Fixes: 30493cc9 ("lib/int_sqrt.c: optimize square root algorithm") Signed-off-by:Anshul Garg <aksgarg1989@gmail.com> Acked-by:
-
Markus Elfring authored
Omit extra messages for a memory allocation failure in these functions. This issue was detected by using the Coccinelle software. Link: http://lkml.kernel.org/r/410a4c5a-4ee0-6fcc-969c-103d8e496b78@users.sourceforge.netSigned-off-by:
Markus Elfring <elfring@users.sourceforge.net> Acked-by:
-
Geert Uytterhoeven authored
Extract the string test code into its own source file, to allow compiling it either to a loadable module, or built into the kernel. Fixes: 03270c13 ("lib/string.c: add testcases for memset16/32/64") Link: http://lkml.kernel.org/r/1505397744-3387-1-git-send-email-geert@linux-m68k.orgSigned-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
-
Masahiro Yamada authored
This include was added by commit 187f1882 ("BUG: headers with BUG/BUG_ON etc. need linux/bug.h") because BUG_ON() was used in this header at that time. Some time later, commit 6d75f366 ("lib: radix-tree: check accounting of existing slot replacement users") removed the use of BUG_ON() from this header. Since then, there is no reason to include <linux/bug.h>. Link: http://lkml.kernel.org/r/1505660151-4383-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by:
-
Masahiro Yamada authored
Since commit bc6245e5 ("bug: split BUILD_BUG stuff out into <linux/build_bug.h>"), #include <linux/build_bug.h> is better to pull minimal headers needed for BUILG_BUG() family. Link: http://lkml.kernel.org/r/1505700775-19826-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by:
Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Dinan Gunawardena <dinan.gunawardena@netronome.com> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Ian Abbott <abbotti@mev.co.uk> Signed-off-by:
-
Joe Perches authored
Add tests for duplicate section headers, missing section content, link and scm reachability. Miscellanea: o Add --self-test=<foo> options (a comma separated list of any of sections, patterns, links or scm) where the default without options is all tests o Rename check_maintainers_patterns to self_test o Rename self_test_pattern_info to self_test_info [tom.saeger@oracle.com: improvements] Link: http://lkml.kernel.org/r/13e3986c374902fcf08ae947e36c5c608bbe3b79.1510075301.git.joe@perches.comSigned-off-by:
Tom Saeger <tom.saeger@oracle.com> Signed-off-by:
-
Tom Saeger authored
Add "--self-test" option to get_maintainer.pl to show potential issues in MAINTAINERS file(s) content. Pattern check warnings are shown for "F" and "X" patterns found in MAINTAINERS file(s) which do not match any files known by git. Link: http://lkml.kernel.org/r/64994f911b3510d0f4c8ac2e113501dfcec1f3c9.1509559540.git.tom.saeger@oracle.comSigned-off-by:
-
Randy Dunlap authored
Fix minor typo. Fix missing words in explaining parsing of last line number. Link: http://lkml.kernel.org/r/ebb7ff42-4945-103f-d5b4-f07a6f3343a7@infradead.orgSigned-off-by:
Randy Dunlap <rdunlap@infradead.org> Cc: Jason Baron <jbaron@akamai.com> Signed-off-by:
-
Randy Dunlap authored
line-range is supposed to treat "1-" as "1-endoffile", so handle the special case by setting last_lineno to UINT_MAX. Fixes this error: dynamic_debug:ddebug_parse_query: last-line:0 < 1st-line:1 dynamic_debug:ddebug_exec_query: query parse failed Link: http://lkml.kernel.org/r/10a6a101-e2be-209f-1f41-54637824788e@infradead.orgSigned-off-by:
-
Christophe JAILLET authored
If 'write' is 0, we can avoid a call to spin_lock/spin_unlock. Link: http://lkml.kernel.org/r/20171020193331.7233-1-christophe.jaillet@wanadoo.frSigned-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Acked-by:
Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by:
-
Sandipan Das authored
The GCC randomize layout plugin can randomize the member offsets of sensitive kernel data structures. To use this feature, certain annotations and members are added to the structures which affect the member offsets even if this plugin is not used. All of these structures are completely randomized, except for task_struct which leaves out some of its members. All the other members are wrapped within an anonymous struct with the __randomize_layout attribute. This is done using the randomized_struct_fields_start and randomized_struct_fields_end defines. When the plugin is disabled, the behaviour of this attribute can vary based on the GCC version. For GCC 5.1+, this attribute maps to __designated_init otherwise it is just an empty define but the anonymous structure is still present. For other compilers, both randomized_struct_fields_start and randomized_struct_fields_end default to empty defines meaning the anonymous structure is not introduced at all. So, if a module compiled with Clang, such as a BPF program, needs to access task_struct fields such as pid and comm, the offsets of these members as recognized by Clang are different from those recognized by modules compiled with GCC. If GCC 4.6+ is used to build the kernel, this can be solved by introducing appropriate defines for Clang so that the anonymous structure is seen when determining the offsets for the members. Link: http://lkml.kernel.org/r/20171109064645.25581-1-sandipan@linux.vnet.ibm.comSigned-off-by:
Sandipan Das <sandipan@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by:
-
Kees Cook authored
Prior to v4.11, x86 used warn_slowpath_fmt() for handling WARN()s. After WARN() was moved to using UD0 on x86, the warning text started appearing _before_ the "cut here" line. This appears to have been a long-standing bug on architectures that used __WARN_TAINT, but it didn't get fixed. v4.11 and earlier on x86: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 2956 at drivers/misc/lkdtm_bugs.c:65 lkdtm_WARNING+0x21/0x30 This is a warning message Modules linked in: v4.12 and later on x86: This is a warning message ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2982 at drivers/misc/lkdtm_bugs.c:68 lkdtm_WARNING+0x15/0x20 Modules linked in: With this fix: ------------[ cut here ]------------ This is a warning message WARNING: CPU: 3 PID: 3009 at drivers/misc/lkdtm_bugs.c:67 lkdtm_WARNING+0x15/0x20 Since the __FILE__ reporting happens as part of the UD0 handler, it isn't trivial to move the message to after the WARNING line, but at least we can fix the position of the "cut here" line so all the various logging tools will start including the actual runtime warning message again, when they follow the instruction and "cut here". Link: http://lkml.kernel.org/r/1510100869-73751-4-git-send-email-keescook@chromium.org Fixes: 9a93848f ("x86/debug: Implement __WARN() using UD0") Signed-off-by:
Kees Cook <keescook@chromium.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by:
-
Kees Cook authored
The "cut here" string is used in a few paths. Define it in a single place. Link: http://lkml.kernel.org/r/1510100869-73751-3-git-send-email-keescook@chromium.orgSigned-off-by:
-
Kees Cook authored
In order to test the ordering of WARN format strings, actually include one in LKDTM. Link: http://lkml.kernel.org/r/1510100869-73751-2-git-send-email-keescook@chromium.orgSigned-off-by:
-
Arnd Bergmann authored
When we pass the result of a multiplication as the timeout or the delay, we can get a warning from gcc-7: drivers/mmc/host/bcm2835.c:596:149: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] drivers/mfd/arizona-core.c:247:195: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c:49:27: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context] The warning is a bit questionable inside of a macro, but this is intentional on the side of the gcc developers. It is also an indication of another problem: we evaluate the timeout and sleep arguments multiple times, which can have undesired side-effects when those are complex expressions. This changes the two iopoll variants to use local variables for storing copies of the timeouts. This adds some more type safety, and avoids both the double-evaluation and the gcc warning. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81484 Link: http://lkml.kernel.org/r/20170726133756.2161367-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20171102114048.1526955-1-arnd@arndb.deSigned-off-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
-
Joe Perches authored
parse-maintainers.pl is convenient, but currently hard-codes the filenames that are used. Allow user-specified filenames to simplify the use of the script. Link: http://lkml.kernel.org/r/48703c068b3235223ffa3b2eb268fa0a125b25e0.1502251549.git.joe@perches.comSigned-off-by:
-
Andi Kleen authored
Some architectures store the WARN_ONCE state in the flags field of the bug_entry. Clear that one too when resetting once state through /sys/kernel/debug/clear_warn_once Pointed out by Michael Ellerman Improves the earlier patch that add clear_warn_once. [ak@linux.intel.com: add a missing ifdef CONFIG_MODULES] Link: http://lkml.kernel.org/r/20171020170633.9593-1-andi@firstfloor.org [akpm@linux-foundation.org: fix unused var warning] [akpm@linux-foundation.org: Use 0200 for clear_warn_once file, per mpe] [akpm@linux-foundation.org: clear BUGFLAG_DONE in clear_once_table(), per mpe] Link: http://lkml.kernel.org/r/20171019204642.7404-1-andi@firstfloor.orgSigned-off-by:
Andi Kleen <ak@linux.intel.com> Tested-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
-
Andi Kleen authored
I like _ONCE warnings because it's guaranteed that they don't flood the log. During testing I find it useful to reset the state of the once warnings, so that I can rerun tests and see if they trigger again, or can guarantee that a test run always hits the same warnings. This patch adds a debugfs interface to reset all the _ONCE warnings so that they appear again: echo 1 > /sys/kernel/debug/clear_warn_once This is implemented by putting all the warning booleans into a special section, and clearing it. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20171017221455.6740-1-andi@firstfloor.orgSigned-off-by:
-
Kees Cook authored
The sh decompressor code triggers stack-protector code generation when using CONFIG_CC_STACKPROTECTOR_STRONG. As done for arm and mips, add a simple static stack-protector canary. As this wasn't protected before, the risk of using a weak canary is minimized. Once the kernel is actually up, a better canary is chosen. Link: http://lkml.kernel.org/r/1506972007-80614-2-git-send-email-keescook@chromium.orgSigned-off-by:
-
Joe Perches authored
Add unnecessary typos by copying the necessary typos. Link: http://lkml.kernel.org/r/1505074722.22023.6.camel@perches.comSigned-off-by:
-
Alexey Dobriyan authored
Gcc doesn't know that "len" is guaranteed to be >=1 by dcache and generates standard while-loop prologue duplicating loop condition. add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27) function old new delta name_to_int 104 77 -27 Link: http://lkml.kernel.org/r/20170912195213.GB17730@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
-
Alexey Dobriyan authored
Save ~360 bytes. add/remove: 1/0 grow/shrink: 0/4 up/down: 104/-463 (-359) function old new delta name_to_int - 104 +104 proc_pid_lookup 217 126 -91 proc_lookupfd_common 212 121 -91 proc_task_lookup 289 194 -95 __proc_create 588 402 -186 Link: http://lkml.kernel.org/r/20170912194850.GA17730@avx2Signed-off-by:
-
Roman Gushchin authored
Right now there is no convenient way to check if a process is being coredumped at the moment. It might be necessary to recognize such state to prevent killing the process and getting a broken coredump. Writing a large core might take significant time, and the process is unresponsive during it, so it might be killed by timeout, if another process is monitoring and killing/restarting hanging tasks. We're getting a significant number of corrupted coredump files on machines in our fleet, just because processes are being killed by timeout in the middle of the core writing process. We do have a process health check, and some agent is responsible for restarting processes which are not responding for health check requests. Writing a large coredump to the disk can easily exceed the reasonable timeout (especially on an overloaded machine). This flag will allow the agent to distinguish processes which are being coredumped, extend the timeout for them, and let them produce a full coredump file. To provide an ability to detect if a process is in the state of being coredumped, we can expose a boolean CoreDumping flag in /proc/pid/status. Example: $ cat core.sh #!/bin/sh echo "|/usr/bin/sleep 10" > /proc/sys/kernel/core_pattern sleep 1000 & PID=$! cat /proc/$PID/status | grep CoreDumping kill -ABRT $PID sleep 1 cat /proc/$PID/status | grep CoreDumping $ ./core.sh CoreDumping: 0 CoreDumping: 1 [guro@fb.com: document CoreDumping flag in /proc/<pid>/status] Link: http://lkml.kernel.org/r/20170928135357.GA8470@castle.DHCP.thefacebook.com Link: http://lkml.kernel.org/r/20170920230634.31572-1-guro@fb.comSigned-off-by:
Roman Gushchin <guro@fb.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Ingo Molnar <mingo@kernel.org> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by:
-
