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/block/paride/pd.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c index 831e3ac..6e28910 100644 --- a/drivers/block/paride/pd.c +++ b/drivers/block/paride/pd.c @@ -723,6 +723,9 @@ static int pd_special_command(struct pd_unit *disk, rq = blk_get_request(disk->gd->queue, READ, __GFP_WAIT); + if (!rq) + return Fail; + rq->cmd_type = REQ_TYPE_SPECIAL; rq->special = func; -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/