fcntl: don't leak fd reference when fixup_compat_flock fails

[ Upstream commit 9280a601 ]

Currently we just return err here, but we need to put the fd reference
first.

Fixes: 94073ad7 (fs/locks: don't mess with the address limit in compat_fcntl64)
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/fcntl.c

@@ -632,8 +632,7 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
 		if (err)
 			break;
 		err = fixup_compat_flock(&flock);
-		if (err)
-			return err;
+		if (!err)
 			err = put_compat_flock(&flock, compat_ptr(arg));
 		break;
 	case F_GETLK64: