Re: workqueue: WARN at at kernel/workqueue.c:2176

From: Jason J. Herne
Date: Wed May 14 2014 - 12:52:25 EST


On 05/12/2014 10:17 PM, Sasha Levin wrote:
I don't have an easy way to reproduce it as I only saw the bug once, but
it happened when I started pressuring CPU hotplug paths by adding and removing
CPUs often. Maybe it has anything to do with that?

As per the original report (http://article.gmane.org/gmane.linux.kernel/1643027)
I am able to reproduce the problem.

The workload is (on S390 architecture):
2 processes onlining random cpus in a tight loop by using 'echo 1 >
/sys/bus/cpu.../online'
2 processes offlining random cpus in a tight loop by using 'echo 0 >
/sys/bus/cpu.../online'
Otherwise, fairly idle system. load average: 5.82, 6.27, 6.27

The machine has 10 processors.
The warning message some times hits within a few minutes on starting the
workload. Other times it takes several hours.


-- Jason J. Herne (jjherne@xxxxxxxxxxxxxxxxxx)

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