Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread Srivatsa S. Bhat
On 10/25/2012 09:02 AM, Michael Wang wrote: > On 10/24/2012 05:38 PM, Peter Zijlstra wrote: >> On Wed, 2012-10-24 at 17:25 +0800, Huacai Chen wrote: >>> We found poweroff sometimes fails on our computers, so we have the >>> lock debug options configured. Then, when we do poweroff or take a >>> cpu

Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread Michael Wang
On 10/24/2012 05:38 PM, Peter Zijlstra wrote: > On Wed, 2012-10-24 at 17:25 +0800, Huacai Chen wrote: >> We found poweroff sometimes fails on our computers, so we have the >> lock debug options configured. Then, when we do poweroff or take a >> cpu down via cpu-hotplug, kernel complain as below. To

Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread 陈华才
> On Wed, 2012-10-24 at 20:34 +0800, 陈华才 wrote: >> I see, this is an arch-specific bug, sorry for my carelessness and thank >> you for your tips. > > What arch are you using? And what exactly did the arch do wrong? Most of > the code involved seems to be common code. > > Going by c0_compare_interr

Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread Peter Zijlstra
On Wed, 2012-10-24 at 20:34 +0800, 陈华才 wrote: > I see, this is an arch-specific bug, sorry for my carelessness and thank > you for your tips. What arch are you using? And what exactly did the arch do wrong? Most of the code involved seems to be common code. Going by c0_compare_interrupt, this is

Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread 陈华才
> On Wed, 2012-10-24 at 17:25 +0800, Huacai Chen wrote: >> We found poweroff sometimes fails on our computers, so we have the >> lock debug options configured. Then, when we do poweroff or take a >> cpu down via cpu-hotplug, kernel complain as below. To resove this, >> we modify sched_ttwu_pending

Re: [RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread Peter Zijlstra
On Wed, 2012-10-24 at 17:25 +0800, Huacai Chen wrote: > We found poweroff sometimes fails on our computers, so we have the > lock debug options configured. Then, when we do poweroff or take a > cpu down via cpu-hotplug, kernel complain as below. To resove this, > we modify sched_ttwu_pending(), dis

[RFC][PATCH] sched: Fix a deadlock of cpu-hotplug

2012-10-24 Thread Huacai Chen
We found poweroff sometimes fails on our computers, so we have the lock debug options configured. Then, when we do poweroff or take a cpu down via cpu-hotplug, kernel complain as below. To resove this, we modify sched_ttwu_pending(), disable the local irq when acquire rq->lock. [ 83.066406]