bfq-iosched: ensure to clear bic/bfqq pointers when preparing request
Even if we don't have an IO context attached to a request, we still
need to clear the priv[0..1] pointers, as they could be pointing
to previously used bic/bfqq structures. If we don't do so, we'll
either corrupt memory on dispatching a request, or cause an
imbalance in counters.
Inspired by a fix from Kees.
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name> Reported-by: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler") Signed-off-by: Jens Axboe <axboe@kernel.dk>