Messages in this thread Patch in this message | | | Date | Wed, 4 Nov 2015 17:59:03 -0800 | From | "Paul E. McKenney" <> | Subject | Re: perf related lockdep bug |
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On Wed, Nov 04, 2015 at 04:55:28PM -0800, Paul E. McKenney wrote: > On Wed, Nov 04, 2015 at 09:58:36PM +0100, Andi Kleen wrote: > > > > I tested my perf stress workload with the patch applied on 4.3, > > unfortunately got a hang again :-/ > > Any diagnostics, sysrq-T output, or whatever?
Given that it looks like your hang is happening at runtime, I would guess that the following patch won't help, but who knows?
Thanx, Paul
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commit 05faf451f1239a28fcd63bf4b66c0db57d7b13f9 Author: Peter Zijlstra <peterz@infradead.org> Date: Wed Nov 4 08:22:05 2015 -0800
rcu: Move wakeup out from under rnp->lock This patch removes a potential deadlock hazard by moving the wake_up_process() in rcu_spawn_gp_kthread() out from under rnp->lock. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index caf3651fa5c9..183445959d00 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4323,8 +4323,8 @@ static int __init rcu_spawn_gp_kthread(void) sp.sched_priority = kthread_prio; sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); } - wake_up_process(t); raw_spin_unlock_irqrestore(&rnp->lock, flags); + wake_up_process(t); } rcu_spawn_nocb_kthreads(); rcu_spawn_boost_kthreads();
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