blk-mq: Avoid race condition with uninitialized requests

This patch should fix the bug reported in
https://lkml.org/lkml/2014/9/11/249.

We have to initialize at least the atomic_flags and the cmd_flags when
allocating storage for the requests.

Otherwise blk_mq_timeout_check() might dereference uninitialized
pointers when racing with the creation of a request.

Also move the reset of cmd_flags for the initializing code to the point
where a request is freed. So we will never end up with pending flush
request indicators that might trigger dereferences of invalid pointers
in blk_mq_timeout_check().

Cc: [email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Reported-by: Paulo De Rezende Pinatti <[email protected]>
Tested-by: Paulo De Rezende Pinatti <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

0 files changed, 0 insertions, 0 deletions