Messages in this thread Patch in this message | | | Date | Wed, 21 May 2014 09:08:26 -0400 | From | Sasha Levin <> | Subject | Re: sched: spinlock recursion in migrate_swap_stop |
| |
On 05/20/2014 09:03 AM, Sasha Levin wrote: > On 05/20/2014 07:04 AM, Peter Zijlstra wrote: >> > On Mon, May 19, 2014 at 10:05:31PM -0400, Sasha Levin wrote: >>> >> ping? It seems to be easy enough to reproduce on -next, I'd be happy to try >>> >> debug patches/fixes. >> > >> > Does this fuzzing you do also include hotplug? If so, does disabling >> > that make this problem go away? >> > > There were no hotplug operations going on when this happens, so it seems > unrelated.
I've added a small test:
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 927fa33..b5e11c7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1154,6 +1156,7 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p) goto out;
trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); + BUG_ON(cur == p); ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
out:
Which seems to get hit. This sounds like a race with task moving to other cpu maybe?
Thanks, Sasha
| |