| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 53/77] ceph: fix null pointer dereference in discard_cap_releases() | Date | Tue, 13 Jan 2015 23:23:33 -0800 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: "Yan, Zheng" <zheng.z.yan@intel.com>
commit 00bd8edb861eb41d274938cfc0338999d9c593a3 upstream.
send_mds_reconnect() may call discard_cap_releases() after all release messages have been dropped by cleanup_cap_releases()
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Reviewed-by: Sage Weil <sage@inktank.com> Cc: Markus Blank-Burian <burian@muenster.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ceph/mds_client.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)
--- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1461,15 +1461,18 @@ static void discard_cap_releases(struct dout("discard_cap_releases mds%d\n", session->s_mds); - /* zero out the in-progress message */ - msg = list_first_entry(&session->s_cap_releases, - struct ceph_msg, list_head); - head = msg->front.iov_base; - num = le32_to_cpu(head->num); - dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg, num); - head->num = cpu_to_le32(0); - msg->front.iov_len = sizeof(*head); - session->s_num_cap_releases += num; + if (!list_empty(&session->s_cap_releases)) { + /* zero out the in-progress message */ + msg = list_first_entry(&session->s_cap_releases, + struct ceph_msg, list_head); + head = msg->front.iov_base; + num = le32_to_cpu(head->num); + dout("discard_cap_releases mds%d %p %u\n", + session->s_mds, msg, num); + head->num = cpu_to_le32(0); + msg->front.iov_len = sizeof(*head); + session->s_num_cap_releases += num; + } /* requeue completed messages */ while (!list_empty(&session->s_cap_releases_done)) {
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