Messages in this thread | | | Date | Thu, 16 Jun 2016 15:39:05 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH 2/2] workqueue:Fix affinity of an unbound worker of a node with 1 online CPU |
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On Thu, Jun 16, 2016 at 02:45:48PM +0200, Peter Zijlstra wrote: > Subject: workqueue: Fix setting affinity of unbound worker threads > From: Peter Zijlstra <peterz@infradead.org> > Date: Thu Jun 16 14:38:42 CEST 2016 > > With commit e9d867a67fd03ccc ("sched: Allow per-cpu kernel threads to > run on online && !active"), __set_cpus_allowed_ptr() expects that only > strict per-cpu kernel threads can have affinity to an online CPU which > is not yet active. > > This assumption is currently broken in the CPU_ONLINE notification > handler for the workqueues where restore_unbound_workers_cpumask() > calls set_cpus_allowed_ptr() when the first cpu in the unbound > worker's pool->attr->cpumask comes online. Since > set_cpus_allowed_ptr() is called with pool->attr->cpumask in which > only one CPU is online which is not yet active, we get the following > WARN_ON during an CPU online operation.
Applied to wq/for-4.7-fixes.
Thanks.
-- tejun
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