From owner-svn-src-stable-9@FreeBSD.ORG Sun Jan 11 12:19:50 2015 Return-Path: Delivered-To: svn-src-stable-9@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 80748282; Sun, 11 Jan 2015 12:19:50 +0000 (UTC) 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)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 6B333B6F; Sun, 11 Jan 2015 12:19:50 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id t0BCJoOf087065; Sun, 11 Jan 2015 12:19:50 GMT (envelope-from hselasky@FreeBSD.org) Received: (from hselasky@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id t0BCJouB087064; Sun, 11 Jan 2015 12:19:50 GMT (envelope-from hselasky@FreeBSD.org) Message-Id: <201501111219.t0BCJouB087064@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: hselasky set sender to hselasky@FreeBSD.org using -f From: Hans Petter Selasky Date: Sun, 11 Jan 2015 12:19:50 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r276970 - stable/9/sys/kern X-SVN-Group: stable-9 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable-9@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SVN commit messages for only the 9-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Jan 2015 12:19:50 -0000 Author: hselasky Date: Sun Jan 11 12:19:49 2015 New Revision: 276970 URL: https://svnweb.freebsd.org/changeset/base/276970 Log: MFC r276532 and r276626: The "cnputs_mtx" mutex must be allowed to recurse. Debug prints and/or witness printouts in the console driver clients can cause this mutex to recurse by calls to "printf()" from witness for example. In particular this can happen if "debug.witness.skipspin=0" is set in the boot environment. Modified: stable/9/sys/kern/kern_cons.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/kern/kern_cons.c ============================================================================== --- stable/9/sys/kern/kern_cons.c Sun Jan 11 12:17:27 2015 (r276969) +++ stable/9/sys/kern/kern_cons.c Sun Jan 11 12:19:49 2015 (r276970) @@ -497,6 +497,13 @@ cnputs(char *p) int unlock_reqd = 0; if (use_cnputs_mtx) { + /* + * NOTE: Debug prints and/or witness printouts in + * console driver clients can cause the "cnputs_mtx" + * mutex to recurse. Simply return if that happens. + */ + if (mtx_owned(&cnputs_mtx)) + return; mtx_lock_spin(&cnputs_mtx); unlock_reqd = 1; }