This is a note to let you know that I've just added the patch titled
sched: Make wakeup side and atomic variants of completion API irq safe
to the 2.6.32-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-make-wakeup-side-and-atomic-variants-of-completion-api-irq-safe.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxx> know about it.
>From rjw@xxxxxxx Thu Sep 16 14:03:08 2010
From: Rafael J.Wysocki <rjw@xxxxxxx>
Date: Sun, 13 Dec 2009 00:07:30 +0100
Subject: sched: Make wakeup side and atomic variants of completion API irq safe
To: stable <stable@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>, Greg KH <greg@xxxxxxxxx>
Message-ID: <09c3ea5b3483bec5c4181b9dfd61b5da6b15969b.1283514306.git.efault@xxxxxx>
From: Rafael J.Wysocki <rjw@xxxxxxx>
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@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: pm list <linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: David Chinner <david@xxxxxxxxxxxxx>
Cc: Lachlan McIlroy <lachlan@xxxxxxx>
LKML-Reference: <200912130007.30541.rjw@xxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
kernel/sched.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5947,14 +5947,15 @@ EXPORT_SYMBOL(wait_for_completion_killab
*/
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);
Patches currently in stable-queue which might be from rjw@xxxxxxx are
queue-2.6.32/sched-make-wakeup-side-and-atomic-variants-of-completion-api-irq-safe.patch
queue-2.6.32/x86-tsc-fix-a-preemption-leak-in-restore_sched_clock_state.patch
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm
