From owner-svn-src-head@freebsd.org Mon Sep 16 15:16:48 2019 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id E816C12548D; Mon, 16 Sep 2019 15:16:48 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46X8wc5s8Cz3Kfk; Mon, 16 Sep 2019 15:16:48 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id A8204221F1; Mon, 16 Sep 2019 15:16:48 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x8GFGmFJ059901; Mon, 16 Sep 2019 15:16:48 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x8GFGm40059900; Mon, 16 Sep 2019 15:16:48 GMT (envelope-from markj@FreeBSD.org) Message-Id: <201909161516.x8GFGm40059900@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Mon, 16 Sep 2019 15:16:48 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352411 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 352411 X-SVN-Commit-Repository: base 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: 2.1.29 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: Mon, 16 Sep 2019 15:16:49 -0000 Author: markj Date: Mon Sep 16 15:16:48 2019 New Revision: 352411 URL: https://svnweb.freebsd.org/changeset/base/352411 Log: Assert that the refcount value is not VPRC_BLOCKED in vm_page_drop(). VPRC_BLOCKED is a refcount flag used to indicate that a thread is tearing down mappings of a page. When set, it causes attempts to wire a page via a pmap lookup to fail. It should never represent the last reference to a page, so assert this. Suggested by: kib Reviewed by: alc, kib Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D21639 Modified: head/sys/vm/vm_page.h Modified: head/sys/vm/vm_page.h ============================================================================== --- head/sys/vm/vm_page.h Mon Sep 16 15:12:49 2019 (r352410) +++ head/sys/vm/vm_page.h Mon Sep 16 15:16:48 2019 (r352411) @@ -902,13 +902,17 @@ vm_page_in_laundry(vm_page_t m) static inline u_int vm_page_drop(vm_page_t m, u_int val) { + u_int old; /* * Synchronize with vm_page_free_prep(): ensure that all updates to the * page structure are visible before it is freed. */ atomic_thread_fence_rel(); - return (atomic_fetchadd_int(&m->ref_count, -val)); + old = atomic_fetchadd_int(&m->ref_count, -val); + KASSERT(old != VPRC_BLOCKED, + ("vm_page_drop: page %p has an invalid refcount value", m)); + return (old); } /*