Re: [PATCH RT 1/3] rt: Move migrate_disable up in trylocks

From: Sebastian Andrzej Siewior
Date: Fri May 02 2014 - 11:32:04 EST


* Steven Rostedt | 2014-04-30 20:47:58 [-0400]:

>From: Steven Rostedt <rostedt@xxxxxxxxxxx>
>
>The changes to move the migrate_disable() down in the trylocks()
>caused race conditions to appear in the cpu hotplug code. The
>migrate disables must be done before any of the rtmutexes are
>taken, otherwise a lock may be held that prevents hotplug from
>moving forward.
>
>Link: http://lkml.kernel.org/r/20140429201308.63292691@xxxxxxxxxxxxxxxxxx

Okay. I am taking a modified version (so it applies) of this into v3.14
tree. Mike also suggested to drop
migrate_disable-pushd-down-in-atomic_dec_and_spin_lo.patch because we
which is basicaly the some thing. And then we have
migrate_disable-pushd-down-in-rt_spin_trylock_irqsav.patch which we
could drop as well for the same reason.

Sebastian
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