[ 204/221] ceph: dont reference req after put

[Greg Kroah-Hartman]

3.7-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Alex Elder <elder@xxxxxxxxxxx>

(cherry picked from commit 7d5f24812bd182a2471cb69c1c2baf0648332e1f)

In __unregister_request(), there is a call to list_del_init()
referencing a request that was the subject of a call to
ceph_osdc_put_request() on the previous line.  This is not
safe, because the request structure could have been freed
by the time we reach the list_del_init().

Fix this by reversing the order of these lines.

Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
Reviewed-off-by: Sage Weil <sage@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ceph/osd_client.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -873,9 +873,9 @@ static void __unregister_request(struct
 			req->r_osd = NULL;
 	}
 
+	list_del_init(&req->r_req_lru_item);
 	ceph_osdc_put_request(req);
 
-	list_del_init(&req->r_req_lru_item);
 	if (osdc->num_requests == 0) {
 		dout(" no requests, canceling timeout\n");
 		__cancel_osd_timeout(osdc);


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