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=-6.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 955E0C433E3 for ; Wed, 19 Aug 2020 10:39:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F61E2072D for ; Wed, 19 Aug 2020 10:39:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ozlabs-ru.20150623.gappssmtp.com header.i=@ozlabs-ru.20150623.gappssmtp.com header.b="yfTEMu3w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727902AbgHSKjf (ORCPT ); Wed, 19 Aug 2020 06:39:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727120AbgHSKjT (ORCPT ); Wed, 19 Aug 2020 06:39:19 -0400 Received: from mail-pj1-x1041.google.com (mail-pj1-x1041.google.com [IPv6:2607:f8b0:4864:20::1041]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E6C2C061757 for ; Wed, 19 Aug 2020 03:39:19 -0700 (PDT) Received: by mail-pj1-x1041.google.com with SMTP id j13so917776pjd.4 for ; Wed, 19 Aug 2020 03:39:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ozlabs-ru.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=zIxttiS+BRDncePDZJjRgf7jquZLdak2flPyXMfNoe0=; b=yfTEMu3wONXW/zEh8QQNeDSSRt/NQM+6RIiuEK16EalcjGEC/Al9CMN089/UIxJlJA DhVYpcY/WgU0FY2YvLlxe+Rzl366lfASPTEJyLDOxlvQ0mGzLJqXRl430Vm90BLCrco9 h4lXoySAiMe9z65BhCqZMdRXn5RCCYklI1MG6ScHTxvvtagy7vSAnwalM9rapX1CuCrF Ljb5Apd0QH0S+jdf53NhLgdtn5A8dASberRUROkKuKnZ9Od+RIjICTsNCkcTjnX8KcBS +lzY4WOY3PX47kPGM33nOHDfu951ywwD0kCxxWLTIhISbL2ZZCiKWnh6RRYu3h83Sdnv /DSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=zIxttiS+BRDncePDZJjRgf7jquZLdak2flPyXMfNoe0=; b=MVJn9lQzze06bUgPHotwgIJELB0vFYrd5YwLofkHmIB6F4wkfaJT91BNGUu4bYZDTN oh4nj+1y4/GAqjkWkR7tUzz7bBc5zsSVGxqzZ/gqDJ3rfnM/r9m2htVmloidCbG2qXRU aTlwXAvjP/MetssGn3IWyyYgtEIeONUqVQzfAKNByrWM5wiORsHlpVMHNARirzOgpRJ1 9D4gsr7FtCKleeSC+YfeKJKqF5MIUvT68XseNYIQ+kiUjn8zLKgrWtCh7rY11+HFUawa kVvAZ3h02N/AL+zOtQcWjFtNEHyX2ofv7PujEmtxIpeE/I3qDbPTIbiFuGKY/zc7UmeN i60Q== X-Gm-Message-State: AOAM530eY3ig9StQMAnRbHeImDKuYDKHsY4Ro3UIAJ8yBlD7GSaCO20D MO4K/+QbsTmxNJMHA/ehKAuing== X-Google-Smtp-Source: ABdhPJxTeSa+segsZyUfLjrwJ5RLYCA88V/f9rKNUTfXF1raV8HinS3AyWkGzHdiF9AiNJ0EGWrqiA== X-Received: by 2002:a17:90a:154e:: with SMTP id y14mr3745002pja.178.1597833558978; Wed, 19 Aug 2020 03:39:18 -0700 (PDT) Received: from [192.168.10.94] (124-171-83-152.dyn.iinet.net.au. [124.171.83.152]) by smtp.gmail.com with ESMTPSA id i11sm2945834pjg.50.2020.08.19.03.39.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Aug 2020 03:39:18 -0700 (PDT) Subject: Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state To: Nicholas Piggin , peterz@infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Ingo Molnar , Will Deacon References: <20200723105615.1268126-1-npiggin@gmail.com> <20200807111126.GI2674@hirez.programming.kicks-ass.net> <1597220073.mbvcty6ghk.astroid@bobo.none> <20200812103530.GL2674@hirez.programming.kicks-ass.net> <1597735273.s0usqkrlsk.astroid@bobo.none> <20200818154143.GT2674@hirez.programming.kicks-ass.net> <1597793862.l8c4pmmzpq.astroid@bobo.none> From: Alexey Kardashevskiy Autocrypt: addr=aik@ozlabs.ru; keydata= mQINBE+rT0sBEADFEI2UtPRsLLvnRf+tI9nA8T91+jDK3NLkqV+2DKHkTGPP5qzDZpRSH6mD 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ikTJSxWUKmh7OP5mrqhwNe0ezgGiWxxvyNwThOHc5JvpzJLd32VDFilbxgu4Hhnf6LcgZJ2c Zd44XWqUu7FzVOYaSgIvTP0hNrBYm/E6M7yrLbs3JY74fGzPWGRbBUHTZXQEqQnZglXaVB5V ZhSFtHopZnBSCUSNDbB+QGy4B/E++Bb02IBTGl/JxmOwG+kZUnymsPvTtnNIeTLHxN/H/ae0 c7E5M+/NpslPCmYnDjs5qg0/3ihh6XuOGggZQOqrYPC3PnsNs3NxirwOkVPQgO6mXxpuifvJ DG9EMkK8IBXnLulqVk54kf7fE0jT/d8RTtJIA92GzsgdK2rpT1MBKKVffjRFGwN7nQVOzi4T XrB5p+6ML7Bd84xOEGsj/vdaXmz1esuH7BOZAGEZfLRCHJ0GVCSssg== Message-ID: <7fadb5ab-9869-396d-ff5d-c0adb6fc0b35@ozlabs.ru> Date: Wed, 19 Aug 2020 20:39:13 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1597793862.l8c4pmmzpq.astroid@bobo.none> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/08/2020 09:54, Nicholas Piggin wrote: > Excerpts from peterz@infradead.org's message of August 19, 2020 1:41 am: >> On Tue, Aug 18, 2020 at 05:22:33PM +1000, Nicholas Piggin wrote: >>> Excerpts from peterz@infradead.org's message of August 12, 2020 8:35 pm: >>>> On Wed, Aug 12, 2020 at 06:18:28PM +1000, Nicholas Piggin wrote: >>>>> Excerpts from peterz@infradead.org's message of August 7, 2020 9:11 pm: >>>>>> >>>>>> What's wrong with something like this? >>>>>> >>>>>> AFAICT there's no reason to actually try and add IRQ tracing here, it's >>>>>> just a hand full of instructions at the most. >>>>> >>>>> Because we may want to use that in other places as well, so it would >>>>> be nice to have tracing. >>>>> >>>>> Hmm... also, I thought NMI context was free to call local_irq_save/restore >>>>> anyway so the bug would still be there in those cases? >>>> >>>> NMI code has in_nmi() true, in which case the IRQ tracing is disabled >>>> (except for x86 which has CONFIG_TRACE_IRQFLAGS_NMI). >>>> >>> >>> That doesn't help. It doesn't fix the lockdep irq state going out of >>> synch with the actual irq state. The code which triggered this with the >>> special powerpc irq disable has in_nmi() true as well. >> >> Urgh, you're talking about using lockdep_assert_irqs*() from NMI >> context? >> >> If not, I'm afraid I might've lost the plot a little on what exact >> failure case we're talking about. >> > > Hm, I may have been a bit confused actually. Since your Fix > TRACE_IRQFLAGS vs NMIs patch it might now work. > > I'm worried powerpc disables trace irqs trace_hardirqs_off() > before nmi_enter() might still be a problem, but not sure > actually. Alexey did you end up re-testing with Peter's patch The one above in the thread which replaces powerpc_local_irq_pmu_save() with raw_powerpc_local_irq_pmu_save()? It did not compile as there is no raw_powerpc_local_irq_pmu_save() so I may be missing something here. I applied the patch on top of the current upstream and replaced raw_powerpc_local_irq_pmu_save() with raw_local_irq_pmu_save() (which I think was the intention) but I still see the issue. > or current upstream? The upstream 18445bf405cb (13 hours old) also shows the problem. Yours 1/2 still fixes it. > > Thanks, > Nick > -- Alexey