Messages in this thread | | | Date | Mon, 2 Jul 2012 04:35:41 -0700 | From | "Paul E. McKenney" <> | Subject | Re: rcu: BUG: spinlock recursion on CPU#3, trinity-child19/5970 |
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On Mon, Jul 02, 2012 at 12:32:19PM +0200, Peter Zijlstra wrote: > On Fri, 2012-06-29 at 23:40 +0200, Sasha Levin wrote: > > > > The bad news are that what you saw was a lockdep enabled run > > (CONFIG_PROVE_RCU is enabled, and lockdep was enabled). There were no > > lockdep warnings at any point while reproducing it. > > rcu_switch_from() -> rcu_preempt_note_context_switch() is called _after_ > the lockdep context switch annotation. Therefore lockdep things the prev > task isn't holding any locks anymore.
In other words, moving rcu_preempt_note_context_switch() deeper into the scheduler is totally bogus, and I need to move it back out into the original rcu_note_context_switch(), reverting 616c310e (Move PREEMPT_RCU preemption to switch_to() invocation), correct?
Sigh. "It seemed like a good idea at the time."
Thanx, Paul
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