From: Andreas Larsson <andreas@gaisler.com>
Date: Thu, 18 Dec 2014 12:23:23 +0000 (+0100)
Subject: sparc32: destroy_context() and switch_mm() needs to disable interrupts.
X-Git-Tag: omap-for-v3.19/fixes-rc1~40^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=66d0f7ec9f1038452178b1993fc07fd96d30fd38;p=pandora-kernel.git

sparc32: destroy_context() and switch_mm() needs to disable interrupts.

Load balancing can be triggered in the critical sections protected by
srmmu_context_spinlock in destroy_context() and switch_mm() and can hang
the cpu waiting for the rq lock of another cpu that in turn has called
switch_mm hangning on srmmu_context_spinlock leading to deadlock.

So, disable interrupt while taking srmmu_context_spinlock in
destroy_context() and switch_mm() so we don't deadlock.

See also commit 77b838fa1ef0 ("[SPARC64]: destroy_context() needs to disable
interrupts.")

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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