From 5e3283e2920a0bd8a806964d80274b8756e0dd7f Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Tue, 8 Apr 2014 11:08:41 +0100 Subject: [PATCH] dm thin: irqsave must always be used with the pool->lock spinlock Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists") incorrectly stopped disabling irqs when taking the pool's spinlock. Irqs must be disabled when taking the pool's spinlock otherwise a thread could spin_lock(), then get interrupted to service thin_endio() in interrupt context, which would then deadlock in spin_lock_irqsave(). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-thin.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 53728be84dee..ae5fd0b9c75c 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3101,6 +3101,7 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) struct thin_c *tc; struct dm_dev *pool_dev, *origin_dev; struct mapped_device *pool_md; + unsigned long flags; mutex_lock(&dm_thin_pool_table.mutex); @@ -3191,9 +3192,9 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) mutex_unlock(&dm_thin_pool_table.mutex); - spin_lock(&tc->pool->lock); + spin_lock_irqsave(&tc->pool->lock, flags); list_add_tail_rcu(&tc->list, &tc->pool->active_thins); - spin_unlock(&tc->pool->lock); + spin_unlock_irqrestore(&tc->pool->lock, flags); /* * This synchronize_rcu() call is needed here otherwise we risk a * wake_worker() call finding no bios to process (because the newly