[PATCH] ide: fix for potential NULL-pointer dereference

[Nikolay Burykin]

After having been compared to NULL value at ide-io.c:370,
pointer 'rq->rq_disk' is dereferenced at ide-io.c:381.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Nikolay Burykin <burikin@xxxxxx>
---
 drivers/ide/ide-io.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 4867b67b60d6..343e93824b03 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -367,7 +367,11 @@ static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 			    pm->pm_step == IDE_PM_COMPLETED)
 				ide_complete_pm_rq(drive, rq);
 			return startstop;
-		} else if (!rq->rq_disk && ata_misc_request(rq))
+		} else if (!rq->rq_disk) {
+			if (!ata_misc_request(rq)) {
+				rq->rq_flags |= RQF_FAILED;
+				goto kill_rq;
+			}
 			/*
 			 * TODO: Once all ULDs have been modified to
 			 * check for specific op codes rather than
@@ -377,6 +381,7 @@ static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 			 * dropped entirely.
 			 */
 			return ide_special_rq(drive, rq);
+		}
 
 		drv = *(struct ide_driver **)rq->rq_disk->private_data;
 
-- 
2.38.1