Re: Yet more softlockups.

[Vince Weaver]

On Fri, 12 Jul 2013, Dave Jones wrote:

> 
> Here's a fun trick:
> 
> trinity -c perf_event_open -C4 -q -l off
> 
> Within about a minute, that brings any of my boxes to its knees.
> The softlockup detector starts going nuts, and then the box wedges solid.

are you running with the patch

 [PATCH 1/2] perf: Clone child context from parent context pmu

 https://lkml.org/lkml/2013/7/9/310

It hasn't hit Linus git yet.

It fixes a bug that my perf_fuzzer would hit within seconds but it took me 
over a month of trace bisecting and kernel bisecting to isolate it.

The symptoms were stuck processes and NMI tracebacks leading to hard 
locks.  

With the patch applied my perf_fuzzer (which uses the same perf_event_open 
syscall generator as trinity) runs for hours w/o problems.

Vince
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