Author: kib
Date: Wed Mar 27 11:03:07 2019
New Revision: 345572
URL: https://svnweb.freebsd.org/changeset/base/345572
Log:
MFC r345324:
vm_fault_copy_entry: accept invalid source pages.
Modified:
stable/11/sys/vm/vm_fault.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/vm/vm_fault.c
==============================================================================
--- stable/11/sys/vm/vm_fault.c Wed Mar 27 10:58:37 2019 (r345571)
+++ stable/11/sys/vm/vm_fault.c Wed Mar 27 11:03:07 2019 (r345572)
@@ -1705,8 +1705,7 @@ again:
}
pmap_copy_page(src_m, dst_m);
VM_OBJECT_RUNLOCK(object);
- dst_m->valid = VM_PAGE_BITS_ALL;
- dst_m->dirty = VM_PAGE_BITS_ALL;
+ dst_m->dirty = dst_m->valid = src_m->valid;
} else {
dst_m = src_m;
if (vm_page_sleep_if_busy(dst_m, "fltupg"))
@@ -1719,8 +1718,6 @@ again:
*/
break;
vm_page_xbusy(dst_m);
- KASSERT(dst_m->valid == VM_PAGE_BITS_ALL,
- ("invalid dst page %p", dst_m));
}
VM_OBJECT_WUNLOCK(dst_object);
@@ -1728,9 +1725,18 @@ again:
* Enter it in the pmap. If a wired, copy-on-write
* mapping is being replaced by a write-enabled
* mapping, then wire that new mapping.
+ *
+ * The page can be invalid if the user called
+ * msync(MS_INVALIDATE) or truncated the backing vnode
+ * or shared memory object. In this case, do not
+ * insert it into pmap, but still do the copy so that
+ * all copies of the wired map entry have similar
+ * backing pages.
*/
- pmap_enter(dst_map->pmap, vaddr, dst_m, prot,
- access | (upgrade ? PMAP_ENTER_WIRED : 0), 0);
+ if (dst_m->valid == VM_PAGE_BITS_ALL) {
+ pmap_enter(dst_map->pmap, vaddr, dst_m, prot,
+ access | (upgrade ? PMAP_ENTER_WIRED : 0), 0);
+ }
/*
* Mark it no longer busy, and put it on the active list.
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
