svn commit: r352409 - head/sys/vm

[Mark Johnston]

Author: markj
Date: Mon Sep 16 15:09:31 2019
New Revision: 352409
URL: https://svnweb.freebsd.org/changeset/base/352409

Log:
  Fix a page leak in vm_page_reclaim_run().
  
  After r352110 the attempt to remove mappings of the page being replaced
  may fail if the page is wired.  In this case we must free the replacement
  page.
  
  Reviewed by:	alc, kib
  Sponsored by:	Netflix
  Differential Revision:	https://reviews.freebsd.org/D21639

Modified:
  head/sys/vm/vm_page.c

Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c	Mon Sep 16 15:06:19 2019	(r352408)
+++ head/sys/vm/vm_page.c	Mon Sep 16 15:09:31 2019	(r352409)
@@ -2597,16 +2597,23 @@ retry:
 					}
 
 					/*
-					 * Replace "m" with the new page.  For
-					 * vm_page_replace(), "m" must be busy
-					 * and dequeued.  Finally, change "m"
-					 * as if vm_page_free() was called.
+					 * Unmap the page and check for new
+					 * wirings that may have been acquired
+					 * through a pmap lookup.
 					 */
 					if (object->ref_count != 0 &&
 					    !vm_page_try_remove_all(m)) {
+						vm_page_free(m_new);
 						error = EBUSY;
 						goto unlock;
 					}
+
+					/*
+					 * Replace "m" with the new page.  For
+					 * vm_page_replace(), "m" must be busy
+					 * and dequeued.  Finally, change "m"
+					 * as if vm_page_free() was called.
+					 */
 					m_new->aflags = m->aflags &
 					    ~PGA_QUEUE_STATE_MASK;
 					KASSERT(m_new->oflags == VPO_UNMANAGED,