From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965060AbWLTOAw (ORCPT ); Wed, 20 Dec 2006 09:00:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965066AbWLTOAw (ORCPT ); Wed, 20 Dec 2006 09:00:52 -0500 Received: from tirith.ics.muni.cz ([147.251.4.36]:55168 "EHLO tirith.ics.muni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965060AbWLTOAw (ORCPT ); Wed, 20 Dec 2006 09:00:52 -0500 Message-ID: <458941D1.7070301@gmail.com> Date: Wed, 20 Dec 2006 14:59:45 +0100 From: Jiri Slaby User-Agent: Thunderbird 2.0a1 (X11/20060724) MIME-Version: 1.0 To: Arjan van de Ven CC: Linux kernel mailing list Subject: Re: locking issue (hardirq+softirq+user) References: <45893C1C.60305@gmail.com> <1166622618.3365.1389.camel@laptopd505.fenrus.org> In-Reply-To: <1166622618.3365.1389.camel@laptopd505.fenrus.org> X-Enigmail-Version: 0.94.1.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Muni-Spam-TestIP: 147.251.48.3 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven wrote: > On Wed, 2006-12-20 at 14:35 +0100, Jiri Slaby wrote: >> Hi! >> >> an user still gets NMI watchdog warning, that the machine deadlocked. > > have you tried enabling LOCKDEP ? No, only PROVE_LOCKING, I apply him to turn this on too. >> isr() /* i.e. hardirq context */ >> { >> spin_lock(&lock); >> ... >> spin_unlock(&lock); >> } > > this is ok if you are 100% sure that this never gets called in any other > way It holds. Only in request_irq isr function name occurs. >> timer() /* i.e. softirq context */ >> { >> unsigned int f; >> spin_lock_irqsave(&lock, f) /* stack shows, that it locks here */ > > this is a bug, the flags are an "unsigned long" not "unsigned int"! > It may do really bad stuff! Aah, sorry, I misread the code, I saw flags, but it was port->flags; board->flags, which is used in irq{save,restore} functions, is ulong. thanks for the quick reply, -- http://www.fi.muni.cz/~xslaby/ Jiri Slaby faculty of informatics, masaryk university, brno, cz e-mail: jirislaby gmail com, gpg pubkey fingerprint: B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E