From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7378C433E0 for ; Thu, 23 Jul 2020 11:40:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83137206C1 for ; Thu, 23 Jul 2020 11:40:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="WXaqbpyD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728461AbgGWLkU (ORCPT ); Thu, 23 Jul 2020 07:40:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726109AbgGWLkU (ORCPT ); Thu, 23 Jul 2020 07:40:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4763DC0619DC; Thu, 23 Jul 2020 04:40:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=kdvkLlB0WIqKZ1XY1QVM6XMLE4+I3RIvWx6RmMkENUQ=; b=WXaqbpyDkFyXzYWsaKmxUO6XOJ NHsi5kiF8SRTNR0efEuOMP5FTHTzkRIaNCVFEdC5pHGcz/+eMpoPOelGZxPcLn0+/n3RGFhPV/HrR YTFn/Bcrr9RL4JHs0NpbYeXnb+iYXKEEXzWvkTHy3eo3Wm1hYnCDil4KbawSbsyUH7BuvckQ9wQOl JSZcc0IE8OqaY3/6zoC8D8rSkfQSpObAfunyAuqz8Ee5zQrEnks0ZVf8k5oHHgWkNt2Zqjias8Kci 5yzCJpOVEsqPUYYaaXTvQIU99DSjitCb13t7fPHUI6CwDAFcq8M7sdabKU1Fr63w/nwpKj/sPvYUM in7glj0A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyZa8-0005JF-MA; Thu, 23 Jul 2020 11:40:12 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 988F49821EE; Thu, 23 Jul 2020 13:40:10 +0200 (CEST) Date: Thu, 23 Jul 2020 13:40:10 +0200 From: Peter Zijlstra To: Nicholas Piggin Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Ingo Molnar , Will Deacon , Alexey Kardashevskiy Subject: Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state Message-ID: <20200723114010.GO5523@worktop.programming.kicks-ass.net> References: <20200723105615.1268126-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200723105615.1268126-1-npiggin@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 23, 2020 at 08:56:14PM +1000, Nicholas Piggin wrote: > diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h > index 3a0db7b0b46e..35060be09073 100644 > --- a/arch/powerpc/include/asm/hw_irq.h > +++ b/arch/powerpc/include/asm/hw_irq.h > @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void) > #define powerpc_local_irq_pmu_save(flags) \ > do { \ > raw_local_irq_pmu_save(flags); \ > - trace_hardirqs_off(); \ > + if (!raw_irqs_disabled_flags(flags)) \ > + trace_hardirqs_off(); \ > } while(0) > #define powerpc_local_irq_pmu_restore(flags) \ > do { \ > - if (raw_irqs_disabled_flags(flags)) { \ > - raw_local_irq_pmu_restore(flags); \ > - trace_hardirqs_off(); \ > - } else { \ > + if (!raw_irqs_disabled_flags(flags)) \ > trace_hardirqs_on(); \ > - raw_local_irq_pmu_restore(flags); \ > - } \ > + raw_local_irq_pmu_restore(flags); \ > } while(0) You shouldn't be calling lockdep from NMI context! That is, I recently added suport for that on x86: https://lkml.kernel.org/r/20200623083721.155449112@infradead.org https://lkml.kernel.org/r/20200623083721.216740948@infradead.org But you need to be very careful on how you order things, as you can see the above relies on preempt_count() already having been incremented with NMI_MASK.