The function blk_get_request() can return NULL in some cases. There are
checks on it if function is called with argumetns one of which is
GFP_ATOMIC/GFP_NOIO/etc. If system couldn't find request
blk_get_request() return NULL.
But if there is function call with argument __GFP_WAIT
the system will wait until get request or the queue becomes
dead. If something kills the queue, blk_get_request()
return NULL and next operations will lead to errors.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Marina Makienko <makie...@ispras.ru>
---
drivers/ide/ide-park.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
index 6ab9ab2..4d178bd 100644
--- a/drivers/ide/ide-park.c
+++ b/drivers/ide/ide-park.c
@@ -32,6 +32,8 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long
timeout)
spin_unlock_irq(&hwif->lock);
rq = blk_get_request(q, READ, __GFP_WAIT);
+ if (!rq)
+ goto out;
rq->cmd[0] = REQ_PARK_HEADS;
rq->cmd_len = 1;
rq->cmd_type = REQ_TYPE_SPECIAL;
--
1.7.7
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