Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 27 Feb 2001 17:41:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 27 Feb 2001 17:41:04 -0500 Received: from horus.its.uow.edu.au ([130.130.68.25]:6379 "EHLO horus.its.uow.edu.au") by vger.kernel.org with ESMTP id ; Tue, 27 Feb 2001 17:40:56 -0500 Message-ID: <3A9C2CE3.ABA1A6A6@uow.edu.au> Date: Tue, 27 Feb 2001 22:40:35 +0000 From: Andrew Morton X-Mailer: Mozilla 4.61 [en] (X11; I; Linux 2.4.1-pre10 i686) X-Accept-Language: en MIME-Version: 1.0 To: Tim Waugh CC: linux-kernel@vger.kernel.org Subject: Re: timing out on a semaphore In-Reply-To: <20010225224039.W13721@redhat.com> <3A9990EF.8D4ECF49@uow.edu.au> <20010227143942.C13721@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tim Waugh wrote: > > On Sun, Feb 25, 2001 at 11:10:39PM +0000, Andrew Morton wrote: > > > I think there might be a bogon in __down_interruptible's > > handling of the semaphore state in this case. I remember > > spotting something a few months back but I can't immediately > > remember what it was :( > > > > I'd suggest you slot a > > > > sema_init(&port->physport->ieee1284.irq, 1); > > > > into parport_wait_event() prior to adding the timer. If that > > fixes it I'll go back through my patchpile, see if I can > > resurrect that grey cell. > > I haven't been able to confirm that it works around it (can't repeat > the problem here), but what would you say if I said it did? ;-) One of two things: 1: Your code is leaving the semaphore in a down'ed state somehow. 2: The semaphore code is leaving the semaphore in a funny state. hmm. I see from your other email that the sema_init() has made the problem go away. Could you please review the code, see if there's an imbalance somewhere? What is parport_ieee1284_write_compat() trying to do with the semaphore? It will leave the semaphore in a downed state. Intentional? Is this code actually being used by the person who is having the problem? Could this loop be replaced by a simple sema_init()? (As you can tell, I'm desparately avoiding having to understand the semaphore code again :)) - - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/