From owner-p4-projects  Tue Mar 11  9:26: 7 2003
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id 8658537B405; Tue, 11 Mar 2003 09:26:04 -0800 (PST)
Delivered-To: perforce@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 1F54937B401
	for <perforce@freebsd.org>; Tue, 11 Mar 2003 09:26:04 -0800 (PST)
Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115])
	by mx1.FreeBSD.org (Postfix) with ESMTP id BB02043FA3
	for <perforce@freebsd.org>; Tue, 11 Mar 2003 09:26:03 -0800 (PST)
	(envelope-from jhb@freebsd.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.12.6/8.12.6) with ESMTP id h2BHQ30U059529
	for <perforce@freebsd.org>; Tue, 11 Mar 2003 09:26:03 -0800 (PST)
	(envelope-from jhb@freebsd.org)
Received: (from perforce@localhost)
	by repoman.freebsd.org (8.12.6/8.12.6/Submit) id h2BHQ309059526
	for perforce@freebsd.org; Tue, 11 Mar 2003 09:26:03 -0800 (PST)
Date: Tue, 11 Mar 2003 09:26:03 -0800 (PST)
Message-Id: <200303111726.h2BHQ309059526@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: perforce set sender to jhb@freebsd.org using -f
From: John Baldwin <jhb@FreeBSD.org>
Subject: PERFORCE change 26687 for review
To: Perforce Change Reviews <perforce@freebsd.org>
Sender: owner-p4-projects@FreeBSD.ORG
Precedence: bulk
List-ID: <p4-projects.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20p4-projects>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20p4-projects>
X-Loop: FreeBSD.ORG

http://perforce.freebsd.org/chv.cgi?CH=26687

Change 26687 by jhb@jhb_laptop on 2003/03/11 09:25:58

	Bah, I think my problem with kldunload was a race condition where
	the next thread destory event was posted before thread 1 had a
	chance to reacquire the event_mtx lock.  Instead, use a cv to
	close this race and similar races when sending events via the
	sysctl.  In evtest_postevent() we wait on this cv after we send
	an event and in event_thread() we signal this cv after setting
	event back to 0.  In thread_destroy() we wait on this cv only if
	the event is not zero after we resume from msleep().

Affected files ...

.. //depot/projects/smpng/sys/modules/evtest/evtest.c#11 edit

Differences ...

==== //depot/projects/smpng/sys/modules/evtest/evtest.c#11 (text+ko) ====

@@ -58,7 +58,7 @@
 #define	EVENT_TYPE_BROADCAST	0x1
 
 static eventhandler_tag first_tag;
-static struct cv event_cv, broadcast_cv;
+static struct cv event_cv, broadcast_cv, event_recvd;
 static struct mtx event_mtx;
 static struct sema evtest_sema;
 static int event, broadcast_count;
@@ -137,6 +137,7 @@
 		event = new_event;
 		cv_signal(&event_cv);
 	}
+	cv_wait(&event_recvd, &event_mtx);
 	mtx_unlock(&event_mtx);
 	return (0);
 }
@@ -245,6 +246,7 @@
 			}
 		}
 		event = 0;
+		cv_signal(&event_recvd);
 		while ((ev = event) == 0)
 			cv_wait(&event_cv, &event_mtx);
 		mtx_unlock(&event_mtx);
@@ -351,6 +353,8 @@
 	cv_broadcast(&event_cv);
 	msleep(threads[i].ti_p, &event_mtx, PWAIT, "evtstun", 0);
 	threads[i].ti_p = NULL;
+	if (event != 0)
+		cv_wait(&event_recvd, &event_mtx);
 }
 
 static void

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe p4-projects" in the body of the message