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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2014-12-05 13:22:22 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-01-14 13:34:15 +0100 |
| commit | 1f8a7633094b7886c0677b78ba60b82e501f3ce6 (patch) | |
| tree | 35b1e774960265e9463b4985dca4f09c3d2b9f26 /lib/stmp_device.c | |
| parent | sched/debug: Check for stack overflow in ___might_sleep() (diff) | |
| download | linux-1f8a7633094b7886c0677b78ba60b82e501f3ce6.tar.xz linux-1f8a7633094b7886c0677b78ba60b82e501f3ce6.zip | |
sched/debug: Fix potential call to __ffs(0) in sched_show_task()
"struct task_struct"->state is "volatile long" and __ffs() warns that
"Undefined if no bit exists, so code should check against 0 first."
Therefore, at expression
state = p->state ? __ffs(p->state) + 1 : 0;
in sched_show_task(), CPU might see "p->state" before "?" as "non-zero"
but "p->state" after "?" as "zero", which could result in
"state >= sizeof(stat_nam)" being true and bogus '?' is printed.
This patch changes "state" from "unsigned int" to "unsigned long" and
save "p->state" before calling __ffs(), in order to avoid potential call
to __ffs(0).
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/201412052131.GCE35924.FVHFOtLOJOMQFS@I-love.SAKURA.ne.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib/stmp_device.c')
0 files changed, 0 insertions, 0 deletions