4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tahsin Erdogan <tahsin@xxxxxxxxxx>
commit d09960b0032174eb493c4c13be5b9c9ef36dc9a7 upstream.
dm_old_request_fn() has paths that access md->io_barrier. The party
destroying io_barrier should ensure that no future execution of
dm_old_request_fn() is possible. Move io_barrier destruction to below
blk_cleanup_queue() to ensure this and avoid a NULL pointer crash during
request-based DM device shutdown.
Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2260,8 +2260,6 @@ static void cleanup_mapped_device(struct
if (md->bs)
bioset_free(md->bs);
- cleanup_srcu_struct(&md->io_barrier);
-
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
@@ -2273,6 +2271,8 @@ static void cleanup_mapped_device(struct
if (md->queue)
blk_cleanup_queue(md->queue);
+ cleanup_srcu_struct(&md->io_barrier);
+
if (md->bdev) {
bdput(md->bdev);
md->bdev = NULL;
--
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