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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 04823C433DB for ; Mon, 22 Feb 2021 11:55:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A960764E09 for ; Mon, 22 Feb 2021 11:55:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229943AbhBVLzM (ORCPT ); Mon, 22 Feb 2021 06:55:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230017AbhBVLzJ (ORCPT ); Mon, 22 Feb 2021 06:55:09 -0500 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72D60C061786 for ; Mon, 22 Feb 2021 03:54:28 -0800 (PST) Received: by mail-wm1-x331.google.com with SMTP id p3so3129014wmc.2 for ; Mon, 22 Feb 2021 03:54:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=U+HxSePe4reaFx3rEe1zCpmNUspu1nuRn9RrICOTQAk=; b=Jhfr/kRrpqIW0E+fGvODAZvYsZJDYLFuvl+C1Wwbv1mX+TK7Xao4GbM+V8Fm9fh+7y U/YAXRP7XGiUyOk9tF8m1JIJF0RKqVOrwrvKcQdWFO+zrifE0bU3gjhVOTXCEOawbWx+ UHsmhpMhNbMCcpwZrXb9iTEHX63fWF3nlpv4FnWsckQmflV47qdqbAov1yALVdrNBIsJ kzKsjq7MNM0C2LR7PhInJznj0addrPWW1Fyk+KN4kEOCdmJJ5RPNIFYiQOZjyhwkSaxd BMP64Rp2lm14jBptprlzl6bsWcWsD6T0n6+C2zVdaO/CAXbSu+3qUjjDMXHWTQ9h2oLu gILw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=U+HxSePe4reaFx3rEe1zCpmNUspu1nuRn9RrICOTQAk=; b=EdRyXncdhsOXRID2U6JceANPg4nnuAJ1tD0T7TjWFa5YFZt0VRXg9+YwpxdbVgxwzP lU0BgIevD7g6ydVDy0OTn4OCu8nC7xFPpAOcQqNCUhe5o3H8kQL2vnnyaunTcNjE2h3G yRH/hXYPoY0Z7ZyZPacoE69Aay61y+qWDK5dVzb2zi0UsnlMSVCAQ/5W78N/kjZd/Acm ssZaigp0WrBAUtY0WtoOkpHPOFVVPY0bHRZJSmRtXGYzvHPJVq49BSGAeFw+WidKQ2zS Fc9OVBrEnJF+OQvT/WE/cJn3Om9Ex6Xvn2oUzIHaE0CSjIHmS3GW4on7FCnsI9WcopoA pHsQ== X-Gm-Message-State: AOAM532d3vldyOI33mu9dtG5/G9M86v7RPGZFiKOGfhjTPaPg+EGTQ+m mqf+p33AansKzZeHuJHS08K+iopGTtB5QQ== X-Google-Smtp-Source: ABdhPJzF+r+O0viVr9hiL7DPwCymq4lroZYNLfbGahHdKAGqoCj1tIPwVPnJYddIskibaa2EnR+EAg== X-Received: by 2002:a1c:f203:: with SMTP id s3mr19538984wmc.152.1613994867101; Mon, 22 Feb 2021 03:54:27 -0800 (PST) Received: from dell ([91.110.221.155]) by smtp.gmail.com with ESMTPSA id y62sm30191077wmy.9.2021.02.22.03.54.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Feb 2021 03:54:26 -0800 (PST) Date: Mon, 22 Feb 2021 11:54:24 +0000 From: Lee Jones To: Zheng Yejian Cc: gregkh@linuxfoundation.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, judy.chenhui@huawei.com, zhangjinhao2@huawei.com, tglx@linutronix.de Subject: Re: [PATCH 4.9.257 1/1] futex: Fix OWNER_DEAD fixup Message-ID: <20210222115424.GF376568@dell> References: <20210222110542.3531596-1-zhengyejian1@huawei.com> <20210222110542.3531596-2-zhengyejian1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210222110542.3531596-2-zhengyejian1@huawei.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, 22 Feb 2021, Zheng Yejian wrote: > From: Peter Zijlstra > > commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream. > > Both Geert and DaveJ reported that the recent futex commit: > > c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") > > introduced a problem with setting OWNER_DEAD. We set the bit on an > uninitialized variable and then entirely optimize it away as a > dead-store. > > Move the setting of the bit to where it is more useful. > > Reported-by: Geert Uytterhoeven > Reported-by: Dave Jones > Signed-off-by: Peter Zijlstra (Intel) > Cc: Andrew Morton > Cc: Linus Torvalds > Cc: Paul E. McKenney > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") > Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net > Signed-off-by: Ingo Molnar > Signed-off-by: Zheng Yejian > --- > kernel/futex.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) Reviewed-by: Lee Jones -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog