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| author | Dmitry Adamushko <dmitry.adamushko@gmail.com> | 2008-07-10 00:32:40 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-10 09:35:34 +0200 |
| commit | dc7fab8b3bb388c57c6c4a43ba68c8a32ca25204 (patch) | |
| tree | 4f96ecc3625b3af71d00592f0e47841b8ab849a7 | |
| parent | 619b0488038224391e64fa03854651ca0f5efe56 (diff) | |
| download | linux-dc7fab8b3bb388c57c6c4a43ba68c8a32ca25204.tar.bz2 | |
sched: fix cpu hotplug
I think we may have a race between try_to_wake_up() and
migrate_live_tasks() -> move_task_off_dead_cpu() when the later one
may end up looping endlessly.
Interrupts are enabled on other CPUs when migration_call(CPU_DEAD, ...) is
called so we may get a race between try_to_wake_up() and
migrate_live_tasks() -> move_task_off_dead_cpu(). The former one may push
a task out of a dead CPU causing the later one to loop endlessly.
Heiko Carstens observed:
| That's exactly what explains a dump I got yesterday. Thanks for fixing! :)
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: miaox@cn.fujitsu.com
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 94ead43eda62..9397b8710138 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5621,8 +5621,10 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) double_rq_lock(rq_src, rq_dest); /* Already moved. */ - if (task_cpu(p) != src_cpu) + if (task_cpu(p) != src_cpu) { + ret = 1; goto out; + } /* Affinity changed (again). */ if (!cpu_isset(dest_cpu, p->cpus_allowed)) goto out; |