tree 1a356ada71b373b363f9fc2204769f8eee920f30
parent aea9058801c0acfa2831af1714da412dfb0018c2
author Alasdair G Kergon <agk@redhat.com> 1238698528 +0100
committer Alasdair G Kergon <agk@redhat.com> 1238698528 +0100

dm table: fix upgrade mode race

upgrade_mode() sets bdev to NULL temporarily, and does not have any
locking to exclude anything from seeing that NULL.

In dm_table_any_congested() bdev_get_queue() can dereference that NULL and
cause a reported oops.

Fix this by not changing that field during the mode upgrade.

Cc: stable@kernel.org
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>