svn commit: r325385 - stable/11/sys/vm

[Konstantin Belousov]

Author: kib
Date: Sat Nov  4 10:10:34 2017
New Revision: 325385
URL: https://svnweb.freebsd.org/changeset/base/325385

Log:
  MFC r324824:
  Check that the page which is freed as zeroed, indeed has all-zero content.

Modified:
  stable/11/sys/vm/vm_page.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/vm/vm_page.c
==============================================================================
--- stable/11/sys/vm/vm_page.c	Sat Nov  4 07:05:21 2017	(r325384)
+++ stable/11/sys/vm/vm_page.c	Sat Nov  4 10:10:34 2017	(r325385)
@@ -2767,6 +2767,16 @@ bool
 vm_page_free_prep(vm_page_t m, bool pagequeue_locked)
 {
 
+#if defined(DIAGNOSTIC) && defined(PHYS_TO_DMAP)
+	if ((m->flags & PG_ZERO) != 0) {
+		uint64_t *p;
+		int i;
+		p = (uint64_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
+		for (i = 0; i < PAGE_SIZE / sizeof(uint64_t); i++, p++)
+			KASSERT(*p == 0, ("vm_page_free_prep %p PG_ZERO %d %jx",
+			    m, i, (uintmax_t)*p));
+	}
+#endif
 	if ((m->oflags & VPO_UNMANAGED) == 0) {
 		vm_page_lock_assert(m, MA_OWNED);
 		KASSERT(!pmap_page_is_mapped(m),