Messages in this thread Patch in this message |  | | | Date | Wed, 15 Sep 2010 10:01:31 GMT | | From | tip-bot for Stanislaw Gruszka <> | | Subject | [tip:sched/urgent] sched: Fix user time incorrectly accounted as system time on 32-bit |
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Commit-ID: e75e863dd5c7d96b91ebbd241da5328fc38a78cc Gitweb: http://git.kernel.org/tip/e75e863dd5c7d96b91ebbd241da5328fc38a78cc Author: Stanislaw Gruszka <sgruszka@redhat.com> AuthorDate: Tue, 14 Sep 2010 16:35:14 +0200 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Wed, 15 Sep 2010 10:41:36 +0200
sched: Fix user time incorrectly accounted as system time on 32-bit
We have 32-bit variable overflow possibility when multiply in task_times() and thread_group_times() functions. When the overflow happens then the scaled utime value becomes erroneously small and the scaled stime becomes i erroneously big.
Reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=633037 https://bugzilla.kernel.org/show_bug.cgi?id=16559
Reported-by: Michael Chapman <redhat-bugzilla@very.puzzling.org> Reported-by: Ciriaco Garcia de Celis <sysman@etherpilot.com> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: <stable@kernel.org> # 2.6.32.19+ (partially) and 2.6.33+ LKML-Reference: <20100914143513.GB8415@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- kernel/sched.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index ed09d4f..dc85ceb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3513,9 +3513,9 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) rtime = nsecs_to_cputime(p->se.sum_exec_runtime); if (total) { - u64 temp; + u64 temp = rtime; - temp = (u64)(rtime * utime); + temp *= utime; do_div(temp, total); utime = (cputime_t)temp; } else @@ -3546,9 +3546,9 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) rtime = nsecs_to_cputime(cputime.sum_exec_runtime); if (total) { - u64 temp; + u64 temp = rtime; - temp = (u64)(rtime * cputime.utime); + temp *= cputime.utime; do_div(temp, total); utime = (cputime_t)temp; } else
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