From 663ae2cc04773608e1e741f693e41200fd4faf14 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Mon, 16 May 2016 13:18:57 +0200 Subject: [PATCH] rbd: get/put img_request in rbd_img_request_submit() By the time we get to checking for_each_obj_request_safe(img_request) terminating condition, all obj_requests may be complete and img_request ref, that rbd_img_request_submit() takes away from its caller, may be put. Moving the next_obj_request cursor is then a use-after-free on img_request. It's totally benign, as the value that's read is never used, but I think it's still worth fixing. Cc: Alex Elder Signed-off-by: Ilya Dryomov --- drivers/block/rbd.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 0ede6d7e2568..c3089f32a392 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -2973,17 +2973,20 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request) { struct rbd_obj_request *obj_request; struct rbd_obj_request *next_obj_request; + int ret = 0; dout("%s: img %p\n", __func__, img_request); - for_each_obj_request_safe(img_request, obj_request, next_obj_request) { - int ret; + rbd_img_request_get(img_request); + for_each_obj_request_safe(img_request, obj_request, next_obj_request) { ret = rbd_img_obj_request_submit(obj_request); if (ret) - return ret; + goto out_put_ireq; } - return 0; +out_put_ireq: + rbd_img_request_put(img_request); + return ret; } static void rbd_img_parent_read_callback(struct rbd_img_request *img_request) -- 2.20.1