From owner-p4-projects Sat Jul 27 16:20:53 2002 Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id DC3B337B401; Sat, 27 Jul 2002 16:20:48 -0700 (PDT) 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 79DBC37B400 for ; Sat, 27 Jul 2002 16:20:48 -0700 (PDT) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id BED8943E4A for ; Sat, 27 Jul 2002 16:20:47 -0700 (PDT) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.12.4/8.12.4) with SMTP id g6RNKdOo025840; Sat, 27 Jul 2002 19:20:39 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Sat, 27 Jul 2002 19:20:38 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: Bosko Milekic Cc: Perforce Change Reviews Subject: Re: PERFORCE change 14877 for review In-Reply-To: <20020724224812.A1630@unixdaemons.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-p4-projects@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, 24 Jul 2002, Bosko Milekic wrote: > On Wed, Jul 24, 2002 at 07:21:38PM -0700, Robert Watson wrote: > > http://people.freebsd.org/~peter/p4db/chv.cgi?CH=14877 > > > > Change 14877 by rwatson@rwatson_curry on 2002/07/24 19:21:02 > > > > Hopefully a bug fix for a bug whereby when one pipe end is > > terminated, the label is prematurely destroyed, resulting in > > a blank label during follow-up policy checks. I believe this > > change modifies the logic so that the pipe label is destroyed > > only when the second end-point is removed. We'll see if this > > corrects the problem I'm bumping into. > > Since you have one mutex and one label for both ends of the > bi-directional pipe, why don't you just use the code already in place > for destroying the mutex 'safely' to also destroy the label? In > other words, pipeclose() has this `hadpeer' variable which it > increments if it finds that the other end exists (and the mutex is > grabbed, then). In other words, just group the label destroy with > the mutex destroy. If one is wrong, they're both wrong and you can > fix them both at the same time. I think that you should only be > destroying the label if it hasn't already been initialized, as well. > It could be that this is a partially created pipe and so the mutex > (and possibly the label?) have not yet been created. I would examine > this further myself but it'll have to wait... :-( Yeah, I think there may be windows where for fdesc-shared processes (and presumably KSE's), the pipe is present but not yet available. An interesting question is whether you can perform pipe operations in the window, and if so, whether we need to initialize the labels earlier, and destroy them later. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe p4-projects" in the body of the message