null_blk: fix use-after-free error

blk_end_request_all may free request, so we need to save
request_queue pointer before blk_end_request_all call.

The problem was introduced in commit cf8ecc5a84
("null_blk: guarantee device restart in all irq modes")
and causes general protection fault with slab poisoning
enabled.

Fixes: cf8ecc5a84 ("null_blk: guarantee device
       restart in all irq modes")

Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Mike Krinkin 2015-12-15 12:56:40 +03:00 коммит произвёл Jens Axboe
Родитель 23688bf4f8
Коммит e827120146
1 изменённых файлов: 3 добавлений и 3 удалений

Просмотреть файл

@ -219,6 +219,9 @@ static void end_cmd(struct nullb_cmd *cmd)
{
struct request_queue *q = NULL;
if (cmd->rq)
q = cmd->rq->q;
switch (queue_mode) {
case NULL_Q_MQ:
blk_mq_end_request(cmd->rq, 0);
@ -232,9 +235,6 @@ static void end_cmd(struct nullb_cmd *cmd)
goto free_cmd;
}
if (cmd->rq)
q = cmd->rq->q;
/* Restart queue if needed, as we are freeing a tag */
if (q && !q->mq_ops && blk_queue_stopped(q)) {
unsigned long flags;