Re: BUG: spinlock recursion on 2.6.14-mm2 when oprofiling

Paul E. McKenney
2005-11-26T05:14:47Z

On Sat, Nov 26, 2005 at 11:39:55AM +0800, Wu Fengguang wrote:
> On Fri, Nov 25, 2005 at 03:28:29PM -0800, Paul E. McKenney wrote:
> > And here is an alternative patch that assumes that the answer to both
> > questions above is "no". It is shorter, though mostly due to use of
> > the list_splice_init() and list_for_each_entry_safe() primitives.
>
> Ok, I'll try it. But it may take time.
>
> Currently I'm running oprofile on linux-2.6.15-rc2-mm1. It seems the bug is not
> quite reproducible. I'll report again if there are any new findings.

Yep, the bug is indeed non-deterministic. For it to happen, softirq
must interrupt a "task_mortuary" critical section, and that softirq
must execute a task-struct RCU callback.

Thanx, Paul