This is a note to let you know that I've just added the patch titled
sched: Fix the broken sched_rr_get_interval()
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-fix-the-broken-sched_rr_get_interval.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a59f4e079d19464eebb9b06513a1d4f55fdae5ba Mon Sep 17 00:00:00 2001
From: Zhu Yanhai <gaoyang.zyh@xxxxxxxxxx>
Date: Tue, 8 Jan 2013 12:56:52 +0800
Subject: sched: Fix the broken sched_rr_get_interval()
From: Zhu Yanhai <gaoyang.zyh@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1357621012-15039-1-git-send-email-gaoyang.zyh@xxxxxxxxxx
[ 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@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
Patches currently in stable-queue which might be from gaoyang.zyh@xxxxxxxxxx are
queue-3.4/sched-fix-the-broken-sched_rr_get_interval.patch
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