On Thu, 2009-10-22 at 20:33 -0300, Kevin Winchester wrote:Hi,
A week or two ago I saw a panic on boot in try_to_wake_up, but it was not
reproducible and I had not written down any trace information. This
evening I saw it twice more, but then on the third boot things worked fine.
This time I copied down the stack trace:
The first time it happened, I remember checking the git logs and it was
Author: Mike Galbraith <efault@xxxxxx>
Date: Fri Oct 9 08:35:03 2009 +0200
sched: Update the clock of runqueue select_task_rq() selected
In try_to_wake_up(), we update the runqueue clock, but
select_task_rq() may select a different runqueue than the one we
updated, leaving the new runqueue's clock stale for a bit.
This patch cures occasional huge latencies reported by latencytop
when coming out of idle on a mostly idle NO_HZ box.
Signed-off-by: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
...so perhaps that has something to do with it.
I don't think that's very likely. Box did explode near my grubby
Config below. Any help would be appreciated.
Building with your config, try_to_wake_up+0x2e is around..
(gdb) list *try_to_wake_up+0x2e
0xffffffff81029107 is in try_to_wake_up (kernel/sched.c:2324).
2319 this_cpu = get_cpu();
2322 rq = orig_rq = task_rq_lock(p, &flags);
2324 if (!(p->state & state))
2325 goto out;
2327 if (p->se.on_rq)
2328 goto out_running;
I don't see how any of that can explode without something very bad
having happened to ksoftirqd before we tried to wake it.