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author | Stanislaw Gruszka <sgruszka@redhat.com> | 2013-04-30 13:35:06 +0400 |
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committer | Ingo Molnar <mingo@kernel.org> | 2013-04-30 21:13:05 +0400 |
commit | 68aa8efcd1ab961e4684ef5af32f72a6ec1911de (patch) | |
tree | ccf6ffe680a1e85f9319c70dcf45f1bba81243e9 /drivers/auxdisplay | |
parent | 772c808a252594692972773f6ee41c289b8e0b2a (diff) | |
download | linux-68aa8efcd1ab961e4684ef5af32f72a6ec1911de.tar.xz |
sched: Avoid prev->stime underflow
Dave Hansen reported strange utime/stime values on his system:
https://lkml.org/lkml/2013/4/4/435
This happens because prev->stime value is bigger than rtime
value. Root of the problem are non-monotonic rtime values (i.e.
current rtime is smaller than previous rtime) and that should be
debugged and fixed.
But since problem did not manifest itself before commit
62188451f0d63add7ad0cd2a1ae269d600c1663d "cputime: Avoid
multiplication overflow on utime scaling", it should be threated
as regression, which we can easily fixed on cputime_adjust()
function.
For now, let's apply this fix, but further work is needed to fix
root of the problem.
Reported-and-tested-by: Dave Hansen <dave@sr71.net>
Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: rostedt@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1367314507-9728-3-git-send-email-sgruszka@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/auxdisplay')
0 files changed, 0 insertions, 0 deletions