Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 11/25] sched: Fix the broken sched_rr_get_interval() | Date | Thu, 8 Aug 2013 18:41:47 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Zhu Yanhai <gaoyang.zyh@taobao.com>
commit a59f4e079d19464eebb9b06513a1d4f55fdae5ba upstream.
The caller of sched_sliced() should pass se.cfs_rq and se as the arguments, however in sched_rr_get_interval() we gave it rq.cfs_rq and se, which made the following computation obviously wrong.
The change was introduced by commit:
77034937dc45 sched: fix crash in sys_sched_rr_get_interval()
... 5 years ago, while it had been the correct 'cfs_rq_of' before the commit. The change seems to be irrelevant to the commit msg, which was to return a 0 timeslice for tasks that are on an idle runqueue. So I believe that was just a plain typo.
Signed-off-by: Zhu Yanhai <gaoyang.zyh@taobao.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Turner <pjt@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1357621012-15039-1-git-send-email-gaoyang.zyh@taobao.com [ Since this is an ABI and an old bug, we'll test this via a slow upstream route, to hopefully discover any app breakage. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5511,7 +5511,7 @@ static unsigned int get_rr_interval_fair * idle runqueue: */ if (rq->cfs.load.weight) - rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); + rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); return rr_interval; }
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