1 files changed, 11 insertions, 0 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 0127a284681..8b8388eca05 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -696,17 +696,28 @@ EXPORT_SYMBOL(posix_test_lock);
  * Note: the above assumption may not be true when handling lock requests
  * from a broken NFS client. But broken NFS clients have a lot more to
  * worry about than proper deadlock detection anyway... --okir
+ *
+ * However, the failure of this assumption (also possible in the case of
+ * multiple tasks sharing the same open file table) also means there's no
+ * guarantee that the loop below will terminate.  As a hack, we give up
+ * after a few iterations.
  */
+
+#define MAX_DEADLK_ITERATIONS 10
+
 static int posix_locks_deadlock(struct file_lock *caller_fl,
                                 struct file_lock *block_fl)
 {
         struct file_lock *fl;
+        int i = 0;
 
 next_task:
         if (posix_same_owner(caller_fl, block_fl))
                 return 1;
         list_for_each_entry(fl, &blocked_list, fl_link) {
                 if (posix_same_owner(fl, block_fl)) {
+                        if (i++ > MAX_DEADLK_ITERATIONS)
+                                return 0;
                         fl = fl->fl_next;
                         block_fl = fl;
                         goto next_task;