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=-9.9 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 0C52DC432C3 for ; Tue, 26 Nov 2019 19:50:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF13D20835 for ; Tue, 26 Nov 2019 19:49:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RlptzD05" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726199AbfKZTt7 (ORCPT ); Tue, 26 Nov 2019 14:49:59 -0500 Received: from mail-pg1-f172.google.com ([209.85.215.172]:41942 "EHLO mail-pg1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbfKZTt6 (ORCPT ); Tue, 26 Nov 2019 14:49:58 -0500 Received: by mail-pg1-f172.google.com with SMTP id 207so9505296pge.8 for ; Tue, 26 Nov 2019 11:49:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:subject:to:cc:message-id:date:user-agent:mime-version :content-language:content-transfer-encoding; bh=15zl+Qd2phUwLHXSf0W8dzNhE08wTuzt1OowuWwLasU=; b=RlptzD05sQPfKEdqN9ncIDMkGSSjPNwd4Sh1EmbOB89KU657sYJiCl1becpAaIl8Kh fnc8PdhDIgqLmefynzDkvFwdNuOZVcOPOeZcC9B8ZsdZ7pmLlb/jmtz1yUQnwnL2WoTd G02WBjFa47aoUhjBAoZ+QzGXncAGnNqAIxfRRi3zFaRmRcdDEddDRO3ym97a1JQtGaYN /v9LrtEX1kQWvFlCSH1HqJBNxqNmWvDTVDRKakP/lc8sZKR8aKyLAz+D90pbeGypLdP/ fm0RdNrehTT3ch1LICaRZ9LosdNCkFjN9lNh6OLFIb1g68kdSdyVa7gDrtNZGph3ydl6 cBIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:message-id:date:user-agent :mime-version:content-language:content-transfer-encoding; bh=15zl+Qd2phUwLHXSf0W8dzNhE08wTuzt1OowuWwLasU=; b=MmDW9glxAi5kTuPRc2x20iAsvqlxJlVZA9cNrhNOeXd3gKWrOMVoAy8no3WYo92Kr6 7C2Ow/sYXQvVw5AynqW1LPDAcvyC05N5gCaMgtX0i7G0+xEhM2YcyB/FXzO+USHHSxQe 589tayu1hORGfzRmykAKehzasLTPk9vQfxJhOm5AEE1rhK3stFgAoIdiN8hTF150nGYc fQORT69pBgV2sqoOXzuw/bunfy4qbZqnv5KtCDGcCJM2MlHKEgkjD88y04HrqMPK+CxZ vARtFIaYvtW+qKA/XfhKdNn6G6bSYkmOlHcy1uw3SmCR/br9CTw/kUvthevn208fUMqa Ukyw== X-Gm-Message-State: APjAAAWuUFqmOtfGt4RHH73qO3ySvADVO1ecSHqG/TK+j1/mST2jDpRU gkck0VxdpPVX+3eNLAYg4vfNig== X-Google-Smtp-Source: APXvYqwdtW1r6IWED9o1iJW79WrWZ43Jde/wxzMDfLa4CNDsYp4vXZZDWyO9wmIy+qse3V3e0kum8g== X-Received: by 2002:a62:e119:: with SMTP id q25mr44001315pfh.161.1574797797660; Tue, 26 Nov 2019 11:49:57 -0800 (PST) Received: from gnomeregan.cam.corp.google.com ([2620:15c:6:14:ad22:1cbb:d8fa:7d55]) by smtp.googlemail.com with ESMTPSA id w2sm13917852pgm.18.2019.11.26.11.49.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 26 Nov 2019 11:49:57 -0800 (PST) From: Barret Rhoden Subject: AVX register corruption from signal delivery To: Sebastian Andrzej Siewior , "Rik van Riel\"" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov Message-ID: Date: Tue, 26 Nov 2019 14:49:55 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed 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 Hi - The Go Team found a bug[1] where the AVX registers can get corrupted during signal delivery. They were able to bisect it to commits related to the "x86: load FPU registers on return to userland" patchset[2]. The bug requires the kernel to be built with GCC 9 to trigger. In particular, arch/x86/kernel/fpu/signal.c needs to be built with GCC 9. Thanks, Barret [1] https://bugzilla.kernel.org/show_bug.cgi?id=205663 [2] https://lore.kernel.org/kvm/20190403164156.19645-1-bigeasy@linutronix.de/