Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754681AbYKFNqw (ORCPT ); Thu, 6 Nov 2008 08:46:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753783AbYKFNqn (ORCPT ); Thu, 6 Nov 2008 08:46:43 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:57755 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753777AbYKFNqm (ORCPT ); Thu, 6 Nov 2008 08:46:42 -0500 Date: Thu, 6 Nov 2008 08:46:39 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Ingo Molnar cc: Zdenek Kabelac , Linux Kernel Mailing List , Peter Zijlstra Subject: Re: sys_sched_yield keeps locked irq before call of schedule() In-Reply-To: <20081106075754.GE8459@elte.hu> Message-ID: References: <20081105130113.GB29548@elte.hu> <20081106075754.GE8459@elte.hu> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1758 Lines: 53 On Thu, 6 Nov 2008, Ingo Molnar wrote: > > * Zdenek Kabelac wrote: > > > > is this some special warning you added? The stock kernel certainly > > > does not emit this warning. > > > > Yes - it's my personal debug checker that tries to watch wether irq > > & irqsafe are running in pair. So it shows a warning if there is a > > call of spin_lock_irq and irq is already dissabled. > > btw., i have added lockdep instrumentation for this two years ago, > it's in the upstream kernel: > > /proc/lockdep_stats: redundant hardirq ons: 7744 > /proc/lockdep_stats: redundant hardirq offs: 1873736 > /proc/lockdep_stats: redundant softirq ons: 0 > /proc/lockdep_stats: redundant softirq offs: 0 > > you could extend the code to trace it. See > kernel/lockdep.c:trace_hardirqs_on_caller(). This bit does it: > > if (unlikely(curr->hardirqs_enabled)) { > debug_atomic_inc(&redundant_hardirqs_on); > return; > } > > you could add a ftrace_printk("redundant hardirq") call right there, > enable ftrace, and enable stack tracing of each trace entry: Quick note. Currently ftrace_printk only shows up if it is set in the iter_ctrl. echo trace_printk > /debug/tracing/iter_ctrl I'll send out a patch to have it on by default. -- Steve > > echo stacktrace > /debug/tracing/iter_ctrl > > then you should see all the call sites in /debug/tracing/trace. > > Ingo > > -- 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/