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/pktcdvd.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index ba66e44..be477aa 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -743,6 +743,9 @@ static int pkt_generic_packet(struct pktcdvd_device *pd,
struct packet_command *
rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
WRITE : READ, __GFP_WAIT);
+ if (!rq)
+ return -EIO;
+
if (cgc->buflen) {
if (blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen,
__GFP_WAIT))
goto out;
--
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/
