Merge tag 'filelock-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux

Pull file locking fixes from Jeff Layton:
 "Just a couple of late-breaking patches for the file locking code. The
  second patch (from yangerkun) fixes a rather nasty looking potential
  use-after-free that should go to stable.

  The other patch could technically wait for 5.7, but it's fairly
  innocuous so I figured we might as well take it"

* tag 'filelock-v5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  locks: fix a potential use-after-free problem when wakeup a waiter
  fcntl: Distribute switch variables for initialization

1 files changed, 0 insertions, 14 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 44b6da032842..426b55d333d5 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -753,20 +753,6 @@ int locks_delete_block(struct file_lock *waiter)
 {
 	int status = -ENOENT;
 
-	/*
-	 * If fl_blocker is NULL, it won't be set again as this thread
-	 * "owns" the lock and is the only one that might try to claim
-	 * the lock.  So it is safe to test fl_blocker locklessly.
-	 * Also if fl_blocker is NULL, this waiter is not listed on
-	 * fl_blocked_requests for some lock, so no other request can
-	 * be added to the list of fl_blocked_requests for this
-	 * request.  So if fl_blocker is NULL, it is safe to
-	 * locklessly check if fl_blocked_requests is empty.  If both
-	 * of these checks succeed, there is no need to take the lock.
-	 */
-	if (waiter->fl_blocker == NULL &&
-	    list_empty(&waiter->fl_blocked_requests))
-		return status;
 	spin_lock(&blocked_lock_lock);
 	if (waiter->fl_blocker)
 		status = 0;