From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757630AbYDUWyy (ORCPT ); Mon, 21 Apr 2008 18:54:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753225AbYDUWyq (ORCPT ); Mon, 21 Apr 2008 18:54:46 -0400 Received: from mx1.redhat.com ([66.187.233.31]:41559 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752520AbYDUWyp (ORCPT ); Mon, 21 Apr 2008 18:54:45 -0400 Message-ID: <480D1B14.7070806@redhat.com> Date: Mon, 21 Apr 2008 18:54:12 -0400 From: Masami Hiramatsu User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Adrian Bunk CC: ananth@in.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, bugme-daemon@bugzilla.kernel.org, jean-marc LACROIX , linux-kernel@vger.kernel.org, Ingo Molnar , Arjan van de Ven Subject: Re: [Bug 10489] Kprobe smoke test lockdep warning References: <20080421150656.GJ6011@cs181133002.pp.htv.fi> In-Reply-To: <20080421150656.GJ6011@cs181133002.pp.htv.fi> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you for reporting. Actually, kprobes tries to fixup thread's flags in post_kprobe_handler (which is called from kprobe_exceptions_notify) by trace_hardirqs_fixup_flags(pt_regs->flags). However, even the irq flag is set in pt_regs->flags, true hardirq is still off until returning from do_debug. Thus, lockdep assumes that hardirq is off without annotation. IMHO, one possible solution is that fixing hardirq flags right after notify_die in do_debug instead of in post_kprobe_handler. Thanks, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: mhiramat@redhat.com