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authorVegard Nossum <vegard.nossum@oracle.com>2013-09-05 13:00:14 +0200
committerJens Axboe <axboe@kernel.dk>2013-11-08 09:10:27 -0700
commitea5ec76d76da9279d12027c1828544c5ccbe7932 (patch)
tree0ce18ebc97696b04df2be341238b977c588b2fb5 /drivers/block
parentc47206e25f28232ff979994c32758c82841d81cd (diff)
downloadlinux-ea5ec76d76da9279d12027c1828544c5ccbe7932.tar.bz2
xen/blkback: fix reference counting
If the permission check fails, we drop a reference to the blkif without having taken it in the first place. The bug was introduced in commit 604c499cbbcc3d5fe5fb8d53306aa0fae1990109 (xen/blkback: Check device permissions before allowing OP_DISCARD). Cc: stable@vger.kernel.org Cc: Jan Beulich <JBeulich@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/xen-blkback/blkback.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index bf4b9d282c04..6620b73d0490 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -887,6 +887,8 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
unsigned long secure;
struct phys_req preq;
+ xen_blkif_get(blkif);
+
preq.sector_number = req->u.discard.sector_number;
preq.nr_sects = req->u.discard.nr_sectors;
@@ -899,7 +901,6 @@ static int dispatch_discard_io(struct xen_blkif *blkif,
}
blkif->st_ds_req++;
- xen_blkif_get(blkif);
secure = (blkif->vbd.discard_secure &&
(req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
BLKDEV_DISCARD_SECURE : 0;