libceph: fix null dereference when unregistering linger requests

We should only clear r_osd if we are neither registered as a linger or a
regular request.  We may unregister as a linger while still registered as
a regular request (e.g., in reset_osd).  Incorrectly clearing r_osd there
leads to a null pointer dereference in __send_request.

Also simplify the parallel check in __unregister_request() where we just
removed r_osd_item and know it's empty.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 03740e8fc9d1..3b91d651fe08 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -837,8 +837,7 @@ static void __unregister_request(struct ceph_osd_client *osdc,
                         dout("moving osd to %p lru\n", req->r_osd);
                         __move_osd_to_lru(osdc, req->r_osd);
                 }
-                if (list_empty(&req->r_osd_item) &&
-                    list_empty(&req->r_linger_item))
+                if (list_empty(&req->r_linger_item))
                         req->r_osd = NULL;
         }
 
@@ -883,7 +882,8 @@ static void __unregister_linger_request(struct ceph_osd_client *osdc,
                         dout("moving osd to %p lru\n", req->r_osd);
                         __move_osd_to_lru(osdc, req->r_osd);
                 }
-                req->r_osd = NULL;
+                if (list_empty(&req->r_osd_item))
+                        req->r_osd = NULL;
         }
 }