diff options
| author | Rafael J.Wysocki <rjw@sisk.pl> | 2009-12-13 00:07:30 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-20 13:17:59 -0700 |
| commit | ad6899b37b13b669b2c52d1a86827d62459760a4 (patch) | |
| tree | 3b5752574d222aba956099397ea9fd7af964739a /kernel | |
| parent | 7a3ca629e89928f038eedc68bc48b2e604fe9711 (diff) | |
sched: Make wakeup side and atomic variants of completion API irq safe
commit 7539a3b3d1f892dd97eaf094134d7de55c13befe upstream
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>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ab6081ea4d3..70cbe4b4a27 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5947,14 +5947,15 @@ EXPORT_SYMBOL(wait_for_completion_killable); */ bool try_wait_for_completion(struct completion *x) { + unsigned long flags; int ret = 1; - spin_lock_irq(&x->wait.lock); + spin_lock_irqsave(&x->wait.lock, flags); if (!x->done) ret = 0; else x->done--; - spin_unlock_irq(&x->wait.lock); + spin_unlock_irqrestore(&x->wait.lock, flags); return ret; } EXPORT_SYMBOL(try_wait_for_completion); @@ -5969,12 +5970,13 @@ EXPORT_SYMBOL(try_wait_for_completion); */ bool completion_done(struct completion *x) { + unsigned long flags; int ret = 1; - spin_lock_irq(&x->wait.lock); + spin_lock_irqsave(&x->wait.lock, flags); if (!x->done) ret = 0; - spin_unlock_irq(&x->wait.lock); + spin_unlock_irqrestore(&x->wait.lock, flags); return ret; } EXPORT_SYMBOL(completion_done); |