From patchwork Fri Aug 12 17:52:44 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Garnier X-Patchwork-Id: 9277559 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CD2D760CDC for ; Fri, 12 Aug 2016 17:53:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C149B28A7E for ; Fri, 12 Aug 2016 17:53:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B5D4D28AC5; Fri, 12 Aug 2016 17:53:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5491828A95 for ; Fri, 12 Aug 2016 17:53:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752923AbcHLRxN (ORCPT ); Fri, 12 Aug 2016 13:53:13 -0400 Received: from mail-pf0-f176.google.com ([209.85.192.176]:35096 "EHLO mail-pf0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752848AbcHLRxM (ORCPT ); Fri, 12 Aug 2016 13:53:12 -0400 Received: by mail-pf0-f176.google.com with SMTP id x72so11060937pfd.2 for ; Fri, 12 Aug 2016 10:53:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=to3/N3O5b1Zo/r6r1UF7fYgxxxBB8jJpXF8D8X+EWc4=; b=I5Zyjsone8WgIVtCv6Ch5zeILO9U+LQZuNrzdcPKymiT8Ez2N62OWmRR++sR8FmEMD ao7KBI9mAO112GYSyQDxMC9ga2+3Q2gyKrNmgQBLVTYy24nFZpakOXYVt2XpMj4X/7b5 lAjvmmvyvfI4vVRLdLUoqbbbUKdujhVm9m63YSaPtAfjIv0xzWk6CsDk/1hy6NVlN4f6 CoqEAptzTOVEjte3VErfd/f6BaPWT/H+BF9e7V3e1MSHyw5u9+LBqC4Sy6aubLj33LQ+ ieotSkfKDwUnjRUy5P6P3z5Au/RtmqfY4QYi3r5CZR0MVn8z7tU0lRKoS0cHt4H13Ajv UqTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=to3/N3O5b1Zo/r6r1UF7fYgxxxBB8jJpXF8D8X+EWc4=; b=mpq3gdwGLm4Ce3iQske3QexHq6pQBbaOovNmKNlWy0pK7QL2V9oypYW3ZoDuWbLxWZ BBpmp7a3u2EJnu+N0UvrYz3EzpdIre3HpZPI8cnCyVfy5n4EY1h9c/8n8UzKS9z3TuIS Sg3gJ1QR/BYiTefkDg0yn3XelKa/pXq5wSSTz8bB0yzkWn0L92yaMmBlphDBk7kEf5TI js9V7Hqt8ciD281ywO/TowuCJpYFMZ9DnYeRnVZPFgcA8nB+AwLu88X8UlIHRqYMDZ5c t7VuUMqQU0eJwszGPrHo2umESipr2dOU5VCL4WMG1+mngMQuyni+bRbP9P5SiImGJAZm n+Dg== X-Gm-Message-State: AEkoouu12nRxYjvlf5/0+eLIinS8wzLP1GMlUcJeSDfLVMePU8AS7v4BOx3FT+UJsz5MFBjj X-Received: by 10.98.111.133 with SMTP id k127mr29066734pfc.90.1471024391779; Fri, 12 Aug 2016 10:53:11 -0700 (PDT) Received: from skynet.sea.corp.google.com ([100.119.232.34]) by smtp.gmail.com with ESMTPSA id c8sm14591909pfe.39.2016.08.12.10.53.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 12 Aug 2016 10:53:11 -0700 (PDT) From: Thomas Garnier To: "Rafael J . Wysocki" , Len Brown , Pavel Machek Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, keescook@chromium.org, kernel-hardening@lists.openwall.com, jikos@kernel.org, bpetkov@suse.de, yinghai@kernel.org, Thomas Garnier Subject: [PATCH v2] x86/power/64: Restore processor state before using per-cpu variables Date: Fri, 12 Aug 2016 10:52:44 -0700 Message-Id: <1471024364-46217-1-git-send-email-thgarnie@google.com> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Restore the processor state before calling any other function to ensure per-cpu variables can be used with KASLR memory randomization. Tracing functions use per-cpu variables (gs based) and one was called just before restoring the processor state fully. It resulted in a double fault when both the tracing & the exception handler functions tried to use a per-cpu variable. Reported-by: Jiri Kosina Tested-by: Jiri Kosina Acked-by: Pavel Machek Reported-and-tested-by: Borislav Petkov Signed-off-by: Thomas Garnier --- Based on next-20160808 Thanks to Rafael, Jiri & Borislav in tracking down this bug and help testing this fix. --- kernel/power/hibernate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index a881c6a..33c79b6 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -300,12 +300,12 @@ static int create_image(int platform_mode) save_processor_state(); trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, true); error = swsusp_arch_suspend(); + /* Restore control flow magically appears here */ + restore_processor_state(); trace_suspend_resume(TPS("machine_suspend"), PM_EVENT_HIBERNATE, false); if (error) printk(KERN_ERR "PM: Error %d creating hibernation image\n", error); - /* Restore control flow magically appears here */ - restore_processor_state(); if (!in_suspend) events_check_enabled = false;