svn commit: r326919 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Mark Johnston]

Author: markj
Date: Sun Dec 17 18:21:40 2017
New Revision: 326919
URL: https://svnweb.freebsd.org/changeset/base/326919

Log:
  Unregister the ARC lowmem event handler earlier in arc_fini().
  
  Otherwise a poorly timed lowmem event may attempt to acquire a destroyed
  lock. Unregister the handler before destroying the ARC reclaim thread.
  
  Reported by:	gjb
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D13480

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c	Sun Dec 17 06:00:49 2017	(r326918)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c	Sun Dec 17 18:21:40 2017	(r326919)
@@ -6619,6 +6619,11 @@ arc_init(void)
 void
 arc_fini(void)
 {
+#ifdef _KERNEL
+	if (arc_event_lowmem != NULL)
+		EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
+#endif
+
 	mutex_enter(&arc_reclaim_lock);
 	arc_reclaim_thread_exit = B_TRUE;
 	/*
@@ -6664,11 +6669,6 @@ arc_fini(void)
 	buf_fini();
 
 	ASSERT0(arc_loaned_bytes);
-
-#ifdef _KERNEL
-	if (arc_event_lowmem != NULL)
-		EVENTHANDLER_DEREGISTER(vm_lowmem, arc_event_lowmem);
-#endif
 }
 
 /*