Date: Wed, 27 Mar 2019 11:03:07 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r345572 - stable/11/sys/vm Message-ID: <201903271103.x2RB375S008283@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
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.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201903271103.x2RB375S008283>