3.11.10.1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Vegard Nossum <vegard.nossum@xxxxxxxxxx> 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@xxxxxxxx> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> --- drivers/block/xen-blkback/blkback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index bf4b9d2..6620b73 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; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html