Messages in this thread Patch in this message | | | Date | Fri, 24 Sep 2010 09:31:49 -0700 | From | Greg KH <> | Subject | [25/68] sched: Fix user time incorrectly accounted as system time on 32-bit |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Stanislaw Gruszka <sgruszka@redhat.com>
commit e75e863dd5c7d96b91ebbd241da5328fc38a78cc upstream.
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> LKML-Reference: <20100914143513.GB8415@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/sched.c +++ b/kernel/sched.c @@ -5341,9 +5341,9 @@ void thread_group_times(struct task_stru 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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