From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763539AbYDVN1B (ORCPT ); Tue, 22 Apr 2008 09:27:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755983AbYDVN0y (ORCPT ); Tue, 22 Apr 2008 09:26:54 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:41563 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754573AbYDVN0x (ORCPT ); Tue, 22 Apr 2008 09:26:53 -0400 Subject: Re: [Bug 10489] Kprobe smoke test lockdep warning From: Peter Zijlstra To: Masami Hiramatsu Cc: Adrian Bunk , 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 In-Reply-To: <1208869770.7115.265.camel@twins> References: <20080421150656.GJ6011@cs181133002.pp.htv.fi> <480D1B14.7070806@redhat.com> <1208869770.7115.265.camel@twins> Content-Type: text/plain Date: Tue, 22 Apr 2008 15:26:31 +0200 Message-Id: <1208870791.7115.269.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2008-04-22 at 15:09 +0200, Peter Zijlstra wrote: > On Mon, 2008-04-21 at 18:54 -0400, Masami Hiramatsu wrote: > > 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. Ah, can you clarrify? pt_regs->flags will only be set when returning to the original trap site? in that case we should not need a lockdep annotation I guess, unless its allowed and exptected for the int3 site to change IRQ state.