From: Ilya Dryomov <idryomov@gmail.com>
Date: Tue, 22 May 2018 14:26:51 +0000 (+0200)
Subject: libceph: avoid a use-after-free during map check
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6001567c14eb8e93f8bceb35fc02158a3e1f20f8;p=linux.git

libceph: avoid a use-after-free during map check

Sending map check after complete_request() was called is not only
useless, but can lead to a use-after-free as req->r_kref decrement in
__complete_request() races with map check code.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
---

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 34b5334548c30..294320400c723 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -2266,7 +2266,7 @@ again:
 		complete_request(req, err);
 	mutex_unlock(&osd->lock);
 
-	if (ct_res == CALC_TARGET_POOL_DNE)
+	if (!err && ct_res == CALC_TARGET_POOL_DNE)
 		send_map_check(req);
 
 	if (promoted)