From: Nicholas Krause <xerofoify@xxxxxxxxx> [ Upstream commit 7296f62f0322d808362b21064deb34f20799c20d ] This adds the needed check after the call to the function mraid_mm_alloc_kioc in order to make sure that this function has not returned NULL and therefore makes sure we do not deference a NULL pointer if one is returned by mraid_mm_alloc_kioc. Further more add needed comments explaining that this function call can return NULL if the list head is empty for the pointer passed in order to allow furture users to understand this required pointer check. Signed-off-by: Nicholas Krause <xerofoify@xxxxxxxxx> Acked-by: Sumit Saxena <sumit.saxena@xxxxxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- drivers/scsi/megaraid/megaraid_mm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/scsi/megaraid/megaraid_mm.c b/drivers/scsi/megaraid/megaraid_mm.c index a706927..4cf9ed9 100644 --- a/drivers/scsi/megaraid/megaraid_mm.c +++ b/drivers/scsi/megaraid/megaraid_mm.c @@ -179,8 +179,12 @@ mraid_mm_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) /* * The following call will block till a kioc is available + * or return NULL if the list head is empty for the pointer + * of type mraid_mmapt passed to mraid_mm_alloc_kioc */ kioc = mraid_mm_alloc_kioc(adp); + if (!kioc) + return -ENXIO; /* * User sent the old mimd_t ioctl packet. Convert it to uioc_t. -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html