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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/[email protected]
Signed-off-by: Jason Baron <[email protected]>
Acked-by: Davidlohr Bueso <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Salman Qazi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Shakeel Butt <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Greg Thelen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.com
Signed-off-by: Joe Perches <[email protected]>
Suggested-by: Vivien Didelot <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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So the line length check can be bypassed by its callers.
Link: http://lkml.kernel.org/r/7de542c08a6e79f2ebe7c1416c9f403c23fdcc09.1508282823.git.joe@perches.com
Signed-off-by: Joe Perches <[email protected]>
Reported-by: Song Liu <[email protected]>
Tested-by: Song Liu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 25528213fe9f ("tags: Fix DEFINE_PER_CPU expansions") for more
details.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Joe Perches <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.com
Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Heinrich Schuchardt <[email protected]>
Acked-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Miles Chen <[email protected]>
Acked-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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
[[email protected]: use correct format string for find-bit tests]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Yury Norov <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Clement Courbet <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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-n805
Signed-off-by: Davidlohr Bueso <[email protected]>
Reported-by: Fengguang Wu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Cheng Jian <[email protected]>
Cc: Kate Stewart <[email protected]>
Cc: Xie XiuQi <[email protected]>
Cc: Li Bin <[email protected]>
Cc: Steven Rostedt (Red Hat) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Don't leak idle function address in NMI backtrace.
Link: http://lkml.kernel.org/r/20171106165648.GA95243@sofia
Signed-off-by: Liu Changcheng <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Stephen Bates <[email protected]>
Reviewed-by: Logan Gunthorpe <[email protected]>
Reviewed-by: Mathieu Desnoyers <[email protected]>
Reviewed-by: Daniel Mentz <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Anshul Garg <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David Miller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michael Davidson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Suggested-by: Joe Perches <[email protected]>
Acked-by: Will Deacon <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Anshul Garg <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David Miller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michael Davidson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Fixes: 30493cc9dddb ("lib/int_sqrt.c: optimize square root algorithm")
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Suggested-by: Anshul Garg <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: David Miller <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Michael Davidson <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Markus Elfring <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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: 03270c13c5ffaa6a ("lib/string.c: add testcases for memset16/32/64")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This include was added by commit 187f1882b5b0 ("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 6d75f366b924 ("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/[email protected]
Signed-off-by: Masahiro Yamada <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Chris Mi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Since commit bc6245e5efd7 ("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/[email protected]
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Cc: Dinan Gunawardena <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: Ian Abbott <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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
[[email protected]: improvements]
Link: http://lkml.kernel.org/r/13e3986c374902fcf08ae947e36c5c608bbe3b79.1510075301.git.joe@perches.com
Signed-off-by: Joe Perches <[email protected]>
Reviewed-by: Tom Saeger <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.com
Signed-off-by: Tom Saeger <[email protected]>
Acked-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Fix minor typo.
Fix missing words in explaining parsing of last line number.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Jason Baron <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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instead of 0
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/[email protected]
Signed-off-by: Randy Dunlap <[email protected]>
Acked-by: Jason Baron <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If 'write' is 0, we can avoid a call to spin_lock/spin_unlock.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Christophe JAILLET <[email protected]>
Acked-by: Luis R. Rodriguez <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Sandipan Das <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Kate Stewart <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Fixes: 9a93848fe787 ("x86/debug: Implement __WARN() using UD0")
Signed-off-by: Kees Cook <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The "cut here" string is used in a few paths. Define it in a single
place.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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In order to test the ordering of WARN format strings, actually include
one in LKDTM.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Mark Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.com
Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.
[[email protected]: add a missing ifdef CONFIG_MODULES]
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: fix unused var warning]
[[email protected]: Use 0200 for clear_warn_once file, per mpe]
[[email protected]: clear BUGFLAG_DONE in clear_once_table(), per mpe]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andi Kleen <[email protected]>
Tested-by: Michael Ellerman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.
[[email protected]: coding-style fixes]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andi Kleen <[email protected]>
Tested-by: Michael Ellerman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Kees Cook <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add unnecessary typos by copying the necessary typos.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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
[[email protected]: document CoreDumping flag in /proc/<pid>/status]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Roman Gushchin <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit f3c931633a59 ("mm, compaction: persistently skip hugetlbfs
pageblocks") has introduced pageblock_skip_persistent() checks into
migration and free scanners, to make sure pageblocks that should be
persistently skipped are marked as such, regardless of the
ignore_skip_hint flag.
Since the previous patch introduced a new no_set_skip_hint flag, the
ignore flag no longer prevents marking pageblocks as skipped. Therefore
we can remove the special cases. The relevant pageblocks will be marked
as skipped by the common logic which marks each pageblock where no page
could be isolated. This makes the code simpler.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Pageblock skip hints were added as a heuristic for compaction, which
shares core code with CMA. Since CMA reliability would suffer from the
heuristics, compact_control flag ignore_skip_hint was added for the CMA
use case. Since 6815bf3f233e ("mm/compaction: respect ignore_skip_hint
in update_pageblock_skip") the flag also means that CMA won't *update*
the skip hints in addition to ignoring them.
Today, direct compaction can also ignore the skip hints in the last
resort attempt, but there's no reason not to set them when isolation
fails in such case. Thus, this patch splits off a new no_set_skip_hint
flag to avoid the updating, which only CMA sets. This should improve
the heuristics a bit, and allow us to simplify the persistent skip bit
handling as the next step.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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pageblock_skip_persistent() checks for HugeTLB pages of pageblock order.
When clearing pageblock skip bits for compaction, the bits are not
cleared for such pageblocks, because they cannot contain base pages
suitable for migration, nor free pages to use as migration targets.
This optimization can be simply extended to all compound pages of order
equal or larger than pageblock order, because migrating such pages (if
they support it) cannot help sub-pageblock fragmentation. This includes
THP's and also gigantic HugeTLB pages, which the current implementation
doesn't persistently skip due to a strict pageblock_order equality check
and not recognizing tail pages.
While THP pages are generally less "persistent" than HugeTLB, we can
still expect that if a THP exists at the point of
__reset_isolation_suitable(), it will exist also during the subsequent
compaction run. The time difference here could be actually smaller than
between a compaction run that sets a (non-persistent) skip bit on a THP,
and the next compaction run that observes it.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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It is pointless to migrate hugetlb memory as part of memory compaction
if the hugetlb size is equal to the pageblock order. No defragmentation
is occurring in this condition.
It is also pointless to for the freeing scanner to scan a pageblock
where a hugetlb page is pinned. Unconditionally skip these pageblocks,
and do so peristently so that they are not rescanned until it is
observed that these hugepages are no longer pinned.
It would also be possible to do this by involving the hugetlb subsystem
in marking pageblocks to no longer be skipped when they hugetlb pages
are freed. This is a simple solution that doesn't involve any
additional subsystems in pageblock skip manipulation.
[[email protected]: fix build]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Rientjes <[email protected]>
Tested-by: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Kcompactd is needlessly ignoring pageblock skip information. It is
doing MIGRATE_SYNC_LIGHT compaction, which is no more powerful than
MIGRATE_SYNC compaction.
If compaction recently failed to isolate memory from a set of
pageblocks, there is nothing to indicate that kcompactd will be able to
do so, or that it is beneficial from attempting to isolate memory.
Use the pageblock skip hint to avoid rescanning pageblocks needlessly
until that information is reset.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Rientjes <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Fix the following warning by removing the unused variable:
mm/shmem.c:3205:27: warning: variable 'info' set but not used [-Wunused-but-set-variable]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Corentin Labbe <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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dma-debug reports the following warning:
WARNING: CPU: 3 PID: 298 at kernel-4.4/lib/dma-debug.c:604
debug _dma_assert_idle+0x1a8/0x230()
DMA-API: cpu touching an active dma mapped cacheline [cln=0x00000882300]
CPU: 3 PID: 298 Comm: vold Tainted: G W O 4.4.22+ #1
Hardware name: MT6739 (DT)
Call trace:
debug_dma_assert_idle+0x1a8/0x230
wp_page_copy.isra.96+0x118/0x520
do_wp_page+0x4fc/0x534
handle_mm_fault+0xd4c/0x1310
do_page_fault+0x1c8/0x394
do_mem_abort+0x50/0xec
I found that debug_dma_alloc_coherent() and debug_dma_free_coherent()
assume that dma_alloc_coherent() always returns a linear address.
However it's possible that dma_alloc_coherent() returns a non-linear
address. In this case, page_to_pfn(virt_to_page(virt)) will return an
incorrect pfn. If the pfn is valid and mapped as a COW page, we will
hit the warning when doing wp_page_copy().
Fix this by calculating pfn for linear and non-linear addresses.
[[email protected]: v4]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Miles Chen <[email protected]>
Reviewed-by: Robin Murphy <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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There is a race in the current z3fold implementation between
do_compact() called in a work queue context and the page release
procedure when page's kref goes to 0.
do_compact() may be waiting for page lock, which is released by
release_z3fold_page_locked right before putting the page onto the
"stale" list, and then the page may be freed as do_compact() modifies
its contents.
The mechanism currently implemented to handle that (checking the
PAGE_STALE flag) is not reliable enough. Instead, we'll use page's kref
counter to guarantee that the page is not released if its compaction is
scheduled. It then becomes compaction function's responsibility to
decrease the counter and quit immediately if the page was actually
freed.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vitaly Wool <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The cleanup caused build warnings for constant mask pointers:
mm/mempolicy.c: In function `mpol_to_str':
./include/linux/nodemask.h:108:11: warning: the comparison will always evaluate as `true' for the address of `nodes' will never be NULL [-Waddress]
An earlier workaround I suggested was incorporated in the version that
got merged, but that only solved the problem for gcc-7 and higher, while
gcc-4.6 through gcc-6.x still warn.
This changes the printing again to use inline functions that make it
clear to the compiler that the line that does the NULL check has no idea
whether the argument is a constant NULL.
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 0205f75571e3 ("mm: simplify nodemask printing")
Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Zhangshaokun <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from
- allow module init functions to be traced
- clean up some unused or not used by config events (saves space)
- clean up of trace histogram code
- add support for preempt and interrupt enabled/disable events
- other various clean ups
* tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits)
tracing, thermal: Hide cpu cooling trace events when not in use
tracing, thermal: Hide devfreq trace events when not in use
ftrace: Kill FTRACE_OPS_FL_PER_CPU
perf/ftrace: Small cleanup
perf/ftrace: Fix function trace events
perf/ftrace: Revert ("perf/ftrace: Fix double traces of perf on ftrace:function")
tracing, dma-buf: Remove unused trace event dma_fence_annotate_wait_on
tracing, memcg, vmscan: Hide trace events when not in use
tracing/xen: Hide events that are not used when X86_PAE is not defined
tracing: mark trace_test_buffer as __maybe_unused
printk: Remove superfluous memory barriers from printk_safe
ftrace: Clear hashes of stale ips of init memory
tracing: Add support for preempt and irq enable/disable events
tracing: Prepare to add preempt and irq trace events
ftrace/kallsyms: Have /proc/kallsyms show saved mod init functions
ftrace: Add freeing algorithm to free ftrace_mod_maps
ftrace: Save module init functions kallsyms symbols for tracing
ftrace: Allow module init functions to be traced
ftrace: Add a ftrace_free_mem() function for modules to use
tracing: Reimplement log2
...
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git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kselftest updates from Shuah Khan:
"This update to Kselftest consists of cleanup patches, fixes, and a new
test for ion buffer sharing.
Fixes include changes to skip firmware tests on systems that aren't
configured to support them, as opposed to failing them"
* tag 'linux-kselftest-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests: firmware: skip unsupported custom firmware fallback tests
selftests: firmware: skip unsupported async loading tests
selftests: memfd_test.c: fix compilation warning.
selftests/ftrace: Introduce exit_pass and exit_fail
selftests: ftrace: add more config fragments
android/ion: userspace test utility for ion buffer sharing
selftests: remove obsolete kconfig fragment for cpu-hotplug
selftests: vdso_test: support ARM64 targets
selftests/ftrace: Do not use arch dependent do_IRQ as a target function
selftests: breakpoints: fix compile error on breakpoint_test_arm64
selftests: add missing test result status in memory-hotplug test
selftests/exec: include cwd in long path calculation
selftests: seccomp: update .gitignore with newly added tests
selftests: vm: Update .gitignore with newly added tests
selftests: timers: Update .gitignore with newly added tests
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