sched: Make wakeup side and atomic variants of completion API irq safe
authorRafael J. Wysocki <rjw@sisk.pl>
Sat, 12 Dec 2009 23:07:30 +0000 (00:07 +0100)
committerIngo Molnar <mingo@elte.hu>
Sun, 13 Dec 2009 07:12:46 +0000 (08:12 +0100)
commit7539a3b3d1f892dd97eaf094134d7de55c13befe
treef49c29135265e452208c5a2e404590f2e0becbc8
parentf40542532e96dda5506eb76badea322f2ae4731c
sched: Make wakeup side and atomic variants of completion API irq safe

Alan Stern noticed that all the wakeup side (and atomic) variants of the
completion APIs should be irq safe, but the newly introduced
completion_done() and try_wait_for_completion() aren't. The use of the
irq unsafe variants in IRQ contexts can cause crashes/hangs.

Fix the problem by making them use spin_lock_irqsave() and
spin_lock_irqrestore().

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Chinner <david@fromorbit.com>
Cc: Lachlan McIlroy <lachlan@sgi.com>
LKML-Reference: <200912130007.30541.rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/sched.c