Messages in this thread Patch in this message | | | Date | Thu, 3 Apr 2014 12:11:03 -0700 | From | David Cohen <> | Subject | Re: Soft lockup regression since kernel 3.13 |
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On Wed, Apr 02, 2014 at 04:29:48PM -0700, David Cohen wrote: > Hi, > > I've detected a regression from upstream (using an Intel Merrifield > device) since 3.13 (still exists in 3.14) which I never had much time > to start to investigate until now. The symptoms are: the device boots > and works fine for while until it silently hangs. > > I finally bisected v3.12..v3.13 and found exactly which commit created > the issue: > > commit f27dde8deef33c9e58027df11ceab2198601d6a6 > Author: Peter Zijlstra <peterz@infradead.org> > Date: Wed Aug 14 14:55:31 2013 +0200 > > sched: Add NEED_RESCHED to the preempt_count
FWIW I did further investigation and made the issue to go away with this hack:
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index c8b051933b1b..41744d99c88f 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -95,7 +95,7 @@ static __always_inline bool __preempt_count_dec_and_test(void) */ static __always_inline bool should_resched(void) { - return unlikely(!__this_cpu_read_4(__preempt_count)); + return unlikely(tif_need_resched()); } #ifdef CONFIG_PREEMPT -- I extended part of this patch to x86:
commit ba1f14fbe70965ae0fb1655a5275a62723f65b77 Author: Peter Zijlstra <peterz@infradead.org> Date: Thu Nov 28 14:26:41 2013 +0100
sched: Remove PREEMPT_NEED_RESCHED from generic code --
Br, David Cohen
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