cifs: Possible slab memory corruption while updating extended stats (…

…repost)

Updating extended statistics here can cause slab memory corruption
if a callback function frees slab memory (mid_entry).

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/connect.c

@@ -633,11 +633,11 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 				mid_entry->largeBuf = isLargeBuf;
 multi_t2_fnd:
 				mid_entry->midState = MID_RESPONSE_RECEIVED;
-				list_del_init(&mid_entry->qhead);
-				mid_entry->callback(mid_entry);
 #ifdef CONFIG_CIFS_STATS2
 				mid_entry->when_received = jiffies;
 #endif
+				list_del_init(&mid_entry->qhead);
+				mid_entry->callback(mid_entry);
 				break;
 			}
 			mid_entry = NULL;