Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5e3283e2 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin: irqsave must always be used with the pool->lock spinlock 



Commit c140e1c4 ("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: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 0596661f

drivers/md/dm-thin.c

+3 −2
Original line number Diff line number Diff line
@@ -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