Re: CFS and suspend2: hang in atomic copy

Ingo Molnar
2007-04-19T06:29:59Z

* Bob Picco <bob.picco@hp.com> wrote:

> I had hoped to collect more data with CFS V2. It crashes in
> scale_nice_down for s2ram when attempting to disable_nonboot_cpus. So
> part of traceback looks like (typed by hand with obvious omissions):
>
> scale_nice_down
> update_stats_wait_end - not shown in traceback because inlined
> pick_next_task_fair
> migration_call
> task_rq_lock
> notifier_call_chain
> _cpu_down
> disable_nonboot_cpus

ok, this looks similar to the jpeg Christian did. Does the patch below
fix the crash for you?

Ingo

---
kernel/sched.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -4425,6 +4425,8 @@ static void migrate_dead_tasks(unsigned
struct task_struct *next;

for (;;) {
+ if (!rq->nr_running)
+ break;
next = pick_next_task(rq, rq->curr);
if (!next)
break;