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 <makienko@xxxxxxxxx> --- drivers/ide/ide-ioctls.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c index 4d19eb9..463f0ff 100644 --- a/drivers/ide/ide-ioctls.c +++ b/drivers/ide/ide-ioctls.c @@ -126,6 +126,8 @@ static int ide_cmd_ioctl(ide_drive_t *drive, unsigned long arg) struct request *rq; rq = blk_get_request(drive->queue, READ, __GFP_WAIT); + if (!rq) + return err; rq->cmd_type = REQ_TYPE_ATA_TASKFILE; err = blk_execute_rq(drive->queue, NULL, rq, 0); blk_put_request(rq); @@ -222,6 +224,8 @@ static int generic_drive_reset(ide_drive_t *drive) int ret = 0; rq = blk_get_request(drive->queue, READ, __GFP_WAIT); + if (!rq) + return ret; rq->cmd_type = REQ_TYPE_SPECIAL; rq->cmd_len = 1; rq->cmd[0] = REQ_DRIVE_RESET; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
