[ 37/54] MD: Add del_timer_sync to mddev_suspend (fix nasty panic)

From: Greg KH
Date: Fri May 18 2012 - 19:26:55 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jonathan Brassow <jbrassow@xxxxxxxxxx>

commit 0d9f4f135eb6dea06bdcb7065b1e4ff78274a5e9 upstream.

Use del_timer_sync to remove timer before mddev_suspend finishes.

We don't want a timer going off after an mddev_suspend is called. This is
especially true with device-mapper, since it can call the destructor function
immediately following a suspend. This results in the removal (kfree) of the
structures upon which the timer depends - resulting in a very ugly panic.
Therefore, we add a del_timer_sync to mddev_suspend to prevent this.

Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/md/md.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -348,6 +348,8 @@ void mddev_suspend(mddev_t *mddev)
synchronize_rcu();
wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
mddev->pers->quiesce(mddev, 1);
+
+ del_timer_sync(&mddev->safemode_timer);
}
EXPORT_SYMBOL_GPL(mddev_suspend);



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