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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 <[email protected]>
Signed-off-by: Erik Ahlén <[email protected]>
Signed-off-by: Spencer Oliver <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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Fix spelling of "concatenation".
Don't use tab after space in indentation.
Signed-off-by: Antonio Borneo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: John Hubbard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Joe Perches <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Cc: Konstantin Ryabitsev <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Joe Perches <[email protected]>
Cc: Rob Herring <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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About 2% of the last 100K commits have email addresses that include an
RFC2822 compliant comment like:
Peter Zijlstra (Intel) <[email protected]>
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 <[email protected]>
Add logic to compare the comment stripped email addresses to avoid this
warning.
Reported-by: Peter Zijlstra <[email protected]>
Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Jason Baron <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/894
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Masahiro Yamada <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Haren Myneni <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: lkml <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Luis Chamberlain <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Michel Lespinasse <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Alex Shi <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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"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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Marco Elver <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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.
[[email protected]: nds32: linker script: add SOFTIRQENTRY_TEXT\
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: add IRQENTRY_TEXT and SOFTIRQENTRY_TEXT to linker script]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Vegard Nossum <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Vegard Nossum <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
Cc: Vegard Nossum <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
From: Dan Carpenter <[email protected]>
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Alexander Potapenko <[email protected]>
Link: http://lkml.kernel.org/r/20200312113006.GA20562@mwanda
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Link: http://lkml.kernel.org/r/202002191358.2897A07C6@keescook
Signed-off-by: Linus Torvalds <[email protected]>
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Add the missing closing parenthesis to the description for the to_buffer
parameter of sg_copy_buffer().
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Akinobu Mita <[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200211205948.GA26459@embeddedor
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200211205813.GA25602@embeddedor
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200211205620.GA24694@embeddedor
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz
Signed-off-by: Linus Torvalds <[email protected]>
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There is a spelling mistake in a pr_notice message. Fix it.
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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
[[email protected]: rename disable_irq to fix build error]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Dmitry Monakhov <[email protected]
Cc: Colin Ian King <[email protected]>
Cc: Guenter Roeck <[email protected]>
Link: http://lkml.kernel.org/r/158132859146.2797.525923171323227836.stgit@buzz
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Chris Wilson <[email protected]>
Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Masahiro Yamada <[email protected]>
Reviewed-by: Daniel Santos <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Ian Abbott <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Miguel Ojeda <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Miller <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Acked-by: Miguel Ojeda <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: David Miller <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/892
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Stefan Asserhall <[email protected]>
Acked-by: Max Filippov <[email protected]> (xtensa)
Cc: Arnd Bergmann <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Link: http://lkml.kernel.org/r/4d32ab4e1fb2edb691d2e1687e8fb303c09fd023.1581504803.git.michal.simek@xilinx.com
Signed-off-by: Linus Torvalds <[email protected]>
|
|
It's clearer to just put this inline.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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) <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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The ppos is a private cursor, just like m->version. Use the canonical
cursor, not a special one.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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) <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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Instead of calling vma_stop() from m_start() and m_next(), do its work
in m_stop().
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200307154435.GA2788@avx2
Signed-off-by: Linus Torvalds <[email protected]>
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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.
[[email protected]: coding style fixes]
Reported-by: kbuild test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Fix sparse locking imbalance warning:
warning: context imbalance in close_pdeo() - unexpected unlock
Signed-off-by: Jules Irenge <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/20200227201538.GA30462@avx2
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Both bootmem_data and bootmem_data_t structures are no longer defined.
Remove the dummy forward declarations.
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Acked-by: Mike Rapoport <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Dan Williams <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: John Hubbard <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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MAX_ZONELISTS is a compile time constant, so it should be compared using
BUILD_BUG_ON not BUG_ON.
Signed-off-by: Mateusz Nosek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Sparse reports a warning at pin_tag()()
warning: context imbalance in pin_tag() - wrong count at exit
The root cause is the missing annotation at pin_tag()
Add the missing __acquires(bitlock) annotation
Signed-off-by: Jules Irenge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Sparse reports a warning at migrate_read_unlock()()
warning: context imbalance in migrate_read_unlock() - unexpected unlock
The root cause is the missing annotation at migrate_read_unlock()
Add the missing __releases(&zspage->lock) annotation
Signed-off-by: Jules Irenge <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
|