From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Weisbecker Subject: Re: linux-next: PowerPC WARN_ON_ONCE() after merge of the final tree (tip related) Date: Thu, 15 Apr 2010 19:24:22 +0200 Message-ID: <20100415172421.GB5069@nowhere> References: <20100415161214.04637496.sfr@canb.auug.org.au> <20100415064940.GA9240@elte.hu> <20100415130032.GA6789@nowhere> <20100415140358.GA19981@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pz0-f204.google.com ([209.85.222.204]:40443 "EHLO mail-pz0-f204.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755152Ab0DORY0 (ORCPT ); Thu, 15 Apr 2010 13:24:26 -0400 Content-Disposition: inline In-Reply-To: <20100415140358.GA19981@elte.hu> Sender: linux-next-owner@vger.kernel.org List-ID: To: Ingo Molnar Cc: Stephen Rothwell , Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, ppc-dev On Thu, Apr 15, 2010 at 04:03:58PM +0200, Ingo Molnar wrote: > > > > > > diff --git a/kernel/lockdep.c b/kernel/lockdep.c > > index 78325f8..65d4336 100644 > > --- a/kernel/lockdep.c > > +++ b/kernel/lockdep.c > > @@ -2298,7 +2298,11 @@ void trace_hardirqs_on_caller(unsigned long ip) > > return; > > > > if (unlikely(curr->hardirqs_enabled)) { > > + unsigned long flags; > > + > > + raw_local_irq_save(flags); > > debug_atomic_inc(redundant_hardirqs_on); > > + raw_local_irq_restore(flags); > > return; > > } > > /* we'll do an OFF -> ON transition: */ > > that looks rather ugly. Why not do a raw: > > this_cpu_inc(lockdep_stats.redundant_hardirqs_on); > > which basically open-codes debug_atomic_inc(), but without the warning? There is also no guarantee we are in a non-preemptable section. We can then also race against another cpu. I'm not sure what to do.