From owner-svn-src-all@FreeBSD.ORG Tue Aug 20 19:13:14 2013 Return-Path: Delivered-To: svn-src-all@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 6A52A6AF; Tue, 20 Aug 2013 19:13:14 +0000 (UTC) (envelope-from bryanv@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 56FFF2590; Tue, 20 Aug 2013 19:13:14 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.7/8.14.7) with ESMTP id r7KJDEsR066629; Tue, 20 Aug 2013 19:13:14 GMT (envelope-from bryanv@svn.freebsd.org) Received: (from bryanv@localhost) by svn.freebsd.org (8.14.7/8.14.5/Submit) id r7KJDENI066628; Tue, 20 Aug 2013 19:13:14 GMT (envelope-from bryanv@svn.freebsd.org) Message-Id: <201308201913.r7KJDENI066628@svn.freebsd.org> From: Bryan Venteicher Date: Tue, 20 Aug 2013 19:13:14 +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: r254578 - 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-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Aug 2013 19:13:14 -0000 Author: bryanv Date: Tue Aug 20 19:13:13 2013 New Revision: 254578 URL: http://svnweb.freebsd.org/changeset/base/254578 Log: MFC r254457 Do not use potentially stale thread in kthread_add() When an existing process is provided, the thread selected to use to initialize the new thread could have exited and be reaped. Acquire the proc lock earlier to ensure the thread remains valid. Modified: stable/9/sys/kern/kern_kthread.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/kern/kern_kthread.c ============================================================================== --- stable/9/sys/kern/kern_kthread.c Tue Aug 20 18:22:04 2013 (r254577) +++ stable/9/sys/kern/kern_kthread.c Tue Aug 20 19:13:13 2013 (r254578) @@ -257,18 +257,17 @@ kthread_add(void (*func)(void *), void * panic("kthread_add called too soon"); /* If no process supplied, put it on proc0 */ - if (p == NULL) { + if (p == NULL) p = &proc0; - oldtd = &thread0; - } else { - oldtd = FIRST_THREAD_IN_PROC(p); - } /* Initialize our new td */ newtd = thread_alloc(pages); if (newtd == NULL) return (ENOMEM); + PROC_LOCK(p); + oldtd = FIRST_THREAD_IN_PROC(p); + bzero(&newtd->td_startzero, __rangeof(struct thread, td_startzero, td_endzero)); /* XXX check if we should zero. */ @@ -293,7 +292,6 @@ kthread_add(void (*func)(void *), void * newtd->td_ucred = crhold(p->p_ucred); /* this code almost the same as create_thread() in kern_thr.c */ - PROC_LOCK(p); p->p_flag |= P_HADTHREADS; newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */ thread_link(newtd, p);