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 <[email protected]> --- drivers/scsi/scsi_error.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 4a6381c..7dd67d4 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1624,6 +1624,9 @@ static void scsi_eh_lock_door(struct scsi_device *sdev) */ req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL); + if (!req) + return; + req->cmd[0] = ALLOW_MEDIUM_REMOVAL; req->cmd[1] = 0; req->cmd[2] = 0; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
