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[2620:137:e000::3:1]) by mx.google.com with ESMTPS id j3-20020a17090aeb0300b002839aba9d89si331696pjz.25.2023.12.07.11.49.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Dec 2023 11:49:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) client-ip=2620:137:e000::3:1; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=cjxnIKza; dkim=neutral (no key) header.i=@linutronix.de; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id 4A6B48050027; Thu, 7 Dec 2023 11:49:34 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230352AbjLGTtT (ORCPT + 99 others); Thu, 7 Dec 2023 14:49:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229800AbjLGTtS (ORCPT ); Thu, 7 Dec 2023 14:49:18 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17E2EA5 for ; Thu, 7 Dec 2023 11:49:25 -0800 (PST) Message-ID: <20231207193859.961361261@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1701978563; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:references:references; bh=2A5tOfBTQ9+8b7wKUOCXmPk6lKlNDwfopIYX+SrqFvY=; b=cjxnIKza2OROijSk2HRt5zAtBnx1RFrbj4lFIq4vCnIjg0akKvRXYrihMqc8Qr+UBEPq8X zgGPPSTNF1dA2iIWqKvHsik6sSyx1K80FYfdTc6AIlQCntpvqnOdvMm3Aha58SHbIDs6Z6 3xzwj/OYdwvkbtI+lmk0bEuASmA6vhIGYsjusXYEwU8GulGvOWkL2FG1M5TSpLw17HpdDM NEEvprhkyg97FXHFR419WBK1X4iAH6iexZcOUAJ1x2bq4vYocb/Ds0rA0LAzElKz8d6fVA PT1qGTWzbjLRZ++PKgX+yOXYO7w4b4jJsSAn3leVxp4KivywVEB+ef0SEY5x8A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1701978563; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:references:references; bh=2A5tOfBTQ9+8b7wKUOCXmPk6lKlNDwfopIYX+SrqFvY=; b=hdLzHWl4dDtnn9kSJymTmjiFU/yETMGR0PDwaRxrgjdhBQLlhlqRWIOH9mnOoj7c4iOYdg nZ3T88HM5jmh7MCg== From: Thomas Gleixner To: LKML Cc: paul.gortmaker@windriver.com, x86@kernel.org, regressions@leemhuis.info, richard.purdie@linuxfoundation.org, regressions@lists.linux.dev References: <0adb772c-e8d2-4444-92b0-00cbfdaf1fac@leemhuis.info> <87r0k9ym0y.ffs@tglx> Subject: [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer Date: Thu, 7 Dec 2023 20:49:22 +0100 (CET) X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Thu, 07 Dec 2023 11:49:34 -0800 (PST) The following series addresses the regression report from Paul on behalf of the yocto project. It turns out that the recent changes to alternatives opened a race window where interrupts are enabled and NOPs are optimized in place. An interrupt hitting into the modification will observe inconsistent text and crash and burn. A 32bit QEMU crashes w/o these fixes reliably within about 50 boot attempts. With the fix applied it survived close to 600 attempts by now. Thanks to Paul for providing all the information! Thanks, tglx