mmc: fix use-after-free of struct request
We call mmc_req_is_special() after having processed a request, but
it could be freed after that. Check that ahead of time, and use
the cached value.
Reported-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Fixes: c2df40dfb8c0 ("drivers: use req op accessor")
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 82503e6..2206d44 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2151,6 +2151,7 @@
struct mmc_card *card = md->queue.card;
struct mmc_host *host = card->host;
unsigned long flags;
+ bool req_is_special = mmc_req_is_special(req);
if (req && !mq->mqrq_prev->req)
/* claim host only for the first request */
@@ -2191,8 +2192,7 @@
}
out:
- if ((!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) ||
- mmc_req_is_special(req))
+ if ((!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) || req_is_special)
/*
* Release host when there are no more requests
* and after special request(discard, flush) is done.
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 29578e9..7080572 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -65,6 +65,8 @@
spin_unlock_irq(q->queue_lock);
if (req || mq->mqrq_prev->req) {
+ bool req_is_special = mmc_req_is_special(req);
+
set_current_state(TASK_RUNNING);
mq->issue_fn(mq, req);
cond_resched();
@@ -80,7 +82,7 @@
* has been finished. Do not assign it to previous
* request.
*/
- if (mmc_req_is_special(req))
+ if (req_is_special)
mq->mqrq_cur->req = NULL;
mq->mqrq_prev->brq.mrq.data = NULL;