From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 4 Sep 2002 18:14:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 4 Sep 2002 18:14:41 -0400 Received: from deimos.hpl.hp.com ([192.6.19.190]:62680 "EHLO deimos.hpl.hp.com") by vger.kernel.org with ESMTP id ; Wed, 4 Sep 2002 18:14:40 -0400 Date: Wed, 4 Sep 2002 15:18:53 -0700 To: Linux kernel mailing list , Jeff Garzik , Alan Cox Subject: Irq handler reentrancy ? Message-ID: <20020904221853.GB21494@bougret.hpl.hp.com> Reply-To: jt@hpl.hp.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.28i Organisation: HP Labs Palo Alto Address: HP Labs, 1U-17, 1501 Page Mill road, Palo Alto, CA 94304, USA. E-mail: jt@hpl.hp.com From: Jean Tourrilhes Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, Just a quick question : can an interrupt handler be preempted or reenter itself ? I know that it can execute in parallel on the various CPUs, so require spin_lock protection. However, on 2.5.32 I see weird bugs that lead me to believe that the irq handler is interrupted at the point where a new hardware interrupt is generated (for example, after clearing the previous irq or after setting the new irq mask). The box just freezes, without giving any Opps or anything on the serial console. Of course, any attempt to add relevant printks make the bug goes away, so it's impossible to debug. 2.4.20 runs fine. Thanks... Jean