From owner-svn-src-head@FreeBSD.ORG Sun Aug 18 21:36:22 2013 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id AE0C579F; Sun, 18 Aug 2013 21:36:22 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 99B302E3A; Sun, 18 Aug 2013 21:36:22 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.7/8.14.7) with ESMTP id r7ILaMxM093196; Sun, 18 Aug 2013 21:36:22 GMT (envelope-from kib@svn.freebsd.org) Received: (from kib@localhost) by svn.freebsd.org (8.14.7/8.14.5/Submit) id r7ILaMAb093192; Sun, 18 Aug 2013 21:36:22 GMT (envelope-from kib@svn.freebsd.org) Message-Id: <201308182136.r7ILaMAb093192@svn.freebsd.org> From: Konstantin Belousov Date: Sun, 18 Aug 2013 21:36:22 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r254501 - head/sys/amd64/amd64 X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Aug 2013 21:36:22 -0000 Author: kib Date: Sun Aug 18 21:36:22 2013 New Revision: 254501 URL: http://svnweb.freebsd.org/changeset/base/254501 Log: When code from r254064 in pmap_ts_referenced() drops pv lock and blocks on a pmap lock, pmap_release() might proceed in parallel and destroy the pmap mutex, since unlocked pv lock allows to remove pv entry owned by the pmap. For now, gate the pmap_release() on write-locked pvh_global_lock. Since pmap_ts_release() does not unlock the global lock, pmap_release() would not destroy pmap mutex until the pmap_ts_referenced() finished. We cannot enter pmap_ts_referenced() and encounter a pv entry for the destroyed pmap if pmap_release() passed the global lock gate, since pmap_remove_pages() would finish earlier. Reported by: jeff, pho Reviewed by: alc Tested by: pho Sponsored by: The FreeBSD Foundation Modified: head/sys/amd64/amd64/pmap.c Modified: head/sys/amd64/amd64/pmap.c ============================================================================== --- head/sys/amd64/amd64/pmap.c Sun Aug 18 20:40:13 2013 (r254500) +++ head/sys/amd64/amd64/pmap.c Sun Aug 18 21:36:22 2013 (r254501) @@ -1959,6 +1959,9 @@ pmap_release(pmap_t pmap) KASSERT(vm_radix_is_empty(&pmap->pm_root), ("pmap_release: pmap has reserved page table page(s)")); + rw_wlock(&pvh_global_lock); + rw_wunlock(&pvh_global_lock); + m = PHYS_TO_VM_PAGE(pmap->pm_pml4[PML4PML4I] & PG_FRAME); for (i = 0; i < NKPML4E; i++) /* KVA */