Messages in this thread Patch in this message | | | From | Marina Makienko <> | Subject | [PATCH 02/13] block: Potential null pointer dereference in pkt_generic_packet() | Date | Thu, 9 Aug 2012 17:54:06 +0400 |
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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@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
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