From owner-svn-src-all@FreeBSD.ORG  Tue Apr  3 07:48:59 2012
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 2A366106564A;
	Tue,  3 Apr 2012 07:48:59 +0000 (UTC)
	(envelope-from fabient@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id 140EB8FC17;
	Tue,  3 Apr 2012 07:48:59 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id q337mwEp037983;
	Tue, 3 Apr 2012 07:48:58 GMT (envelope-from fabient@svn.freebsd.org)
Received: (from fabient@localhost)
	by svn.freebsd.org (8.14.4/8.14.4/Submit) id q337mwEY037981;
	Tue, 3 Apr 2012 07:48:58 GMT (envelope-from fabient@svn.freebsd.org)
Message-Id: <201204030748.q337mwEY037981@svn.freebsd.org>
From: Fabien Thomas <fabient@FreeBSD.org>
Date: Tue, 3 Apr 2012 07:48:58 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
	svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org
X-SVN-Group: stable-8
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r233825 - stable/8/sys/dev/hwpmc
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
	user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 03 Apr 2012 07:48:59 -0000

Author: fabient
Date: Tue Apr  3 07:48:58 2012
New Revision: 233825
URL: http://svn.freebsd.org/changeset/base/233825

Log:
  MFC r233544:
  Fix random deadlock on pmcstat exit:
  - Exit the thread when soft shutdown is requested
  - Wakeup owner thread.
  
  Reproduced/tested by looping pmcstat measurement:
  pmcstat -S instructions -O/tmp/test ls

Modified:
  stable/8/sys/dev/hwpmc/hwpmc_logging.c
Directory Properties:
  stable/8/sys/   (props changed)

Modified: stable/8/sys/dev/hwpmc/hwpmc_logging.c
==============================================================================
--- stable/8/sys/dev/hwpmc/hwpmc_logging.c	Tue Apr  3 07:15:42 2012	(r233824)
+++ stable/8/sys/dev/hwpmc/hwpmc_logging.c	Tue Apr  3 07:48:58 2012	(r233825)
@@ -284,6 +284,7 @@ pmclog_loop(void *arg)
 			if ((lb = TAILQ_FIRST(&po->po_logbuffers)) == NULL) {
 				mtx_unlock_spin(&po->po_mtx);
 
+				/* No more buffers and shutdown required. */
 				if (po->po_flags & PMC_PO_SHUTDOWN) {
 					mtx_unlock(&pmc_kthread_mtx);
 					/*
@@ -292,6 +293,7 @@ pmclog_loop(void *arg)
 					 */
 					fo_close(po->po_file, curthread);
 					mtx_lock(&pmc_kthread_mtx);
+					break;
 				}
 
 				(void) msleep(po, &pmc_kthread_mtx, PWAIT,
@@ -354,6 +356,7 @@ pmclog_loop(void *arg)
 		lb = NULL;
 	}
 
+	wakeup_one(po->po_kthread);
 	po->po_kthread = NULL;
 
 	mtx_unlock(&pmc_kthread_mtx);
@@ -652,8 +655,7 @@ pmclog_deconfigure_log(struct pmc_owner 
 	    ("[pmclog,%d] po=%p no log file", __LINE__, po));
 
 	/* stop the kthread, this will reset the 'OWNS_LOGFILE' flag */
-	if (po->po_kthread)
-		pmclog_stop_kthread(po);
+	pmclog_stop_kthread(po);
 
 	KASSERT(po->po_kthread == NULL,
 	    ("[pmclog,%d] po=%p kthread not stopped", __LINE__, po));