diff options
| author | Vegard Nossum <vegard.nossum@oracle.com> | 2013-09-05 13:00:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-12-04 10:50:30 -0800 |
| commit | fbd604987d9c53f79abd385fc8d510d7e71dac9e (patch) | |
| tree | 6852711fea5c7385233c48b8ccd70e3ce1c2c27d | |
| parent | dc51161bf8064f63470ee718843a1b4fd75d0bb5 (diff) | |
xen/blkback: fix reference counting
commit ea5ec76d76da9279d12027c1828544c5ccbe7932 upstream.
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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 4ed7bf9b4fd1..0ed5df4d3e9f 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -401,6 +401,8 @@ 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; @@ -413,7 +415,6 @@ 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; |