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authorJens Axboe <jens.axboe@oracle.com>2008-11-18 15:07:05 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-11-18 15:08:56 +0100
commitc26156b2534c75bb3cdedf76f6ad1340971cf5bd (patch)
treeb95ed72f569c105fcc9e8f38df3d47628e689059 /block/blk-map.c
parent98ba4031ab2adc8b394295e68aa4c8fe9d5060db (diff)
downloadkernel-c26156b2534c75bb3cdedf76f6ad1340971cf5bd.tar.gz
block: hold extra reference to bio in blk_rq_map_user_iov()
If the size passed in is OK but we end up mapping too many segments, we call the unmap path directly like from IO completion. But from IO completion we have an extra reference to the bio, so this error case goes OOPS when it attempts to free and already free bio. Fix it by getting an extra reference to the bio before calling the unmap failure case. Reported-by: Petr Vandrovec <vandrove@vc.cvut.cz> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-map.c')
-rw-r--r--block/blk-map.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/block/blk-map.c b/block/blk-map.c
index 4849fa36161e..0f4b4b881811 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -217,6 +217,12 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
return PTR_ERR(bio);
if (bio->bi_size != len) {
+ /*
+ * Grab an extra reference to this bio, as bio_unmap_user()
+ * expects to be able to drop it twice as it happens on the
+ * normal IO completion path
+ */
+ bio_get(bio);
bio_endio(bio, 0);
bio_unmap_user(bio);
return -EINVAL;