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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 61BB6C04EBD for ; Tue, 16 Oct 2018 14:26:28 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 756132086E for ; Tue, 16 Oct 2018 14:26:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 756132086E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42ZHg52dMrzF3XB for ; Wed, 17 Oct 2018 01:26:25 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42ZHcT459GzF3Sd for ; Wed, 17 Oct 2018 01:24:09 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 42ZHcT2v0Qz8wRV for ; Wed, 17 Oct 2018 01:24:09 +1100 (AEDT) Received: by ozlabs.org (Postfix) id 42ZHcT1ySxz9s8r; Wed, 17 Oct 2018 01:24:09 +1100 (AEDT) Authentication-Results: ozlabs.org; spf=permerror (mailfrom) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 42ZHcS3Z1wz9sCf for ; Wed, 17 Oct 2018 01:24:08 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w9GENhXA019393; Tue, 16 Oct 2018 09:23:44 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id w9GENf9H019392; Tue, 16 Oct 2018 09:23:41 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 16 Oct 2018 09:23:41 -0500 From: Segher Boessenkool To: Michael Ellerman Subject: Re: Stack protector crash in pnv_smp_cpu_kill_self() Message-ID: <20181016142340.GY29268@gate.crashing.org> References: <87k1mjz6hd.fsf@concordia.ellerman.id.au> <87ftx6kowh.fsf@concordia.ellerman.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ftx6kowh.fsf@concordia.ellerman.id.au> User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linuxppc-dev@ozlabs.org" , Gautham R Shenoy , Nicholas Piggin , Abdul Haleem Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Oct 17, 2018 at 12:21:50AM +1100, Michael Ellerman wrote: > Christophe LEROY writes: > > > Looks like a lack of initialisation of the canary for the non-boot CPUs > > on SMP, you applied this morning the patch I sent you for that. > > > > Is the patch in ? > > Yeah it is. > > $ git log --oneline 4ffe713b7587 arch/powerpc/kernel/smp.c > 8e8a31d7fd54 powerpc: Use cpu_smallcore_sibling_mask at SMT level on bigcores > 425752c63b6f powerpc: Detect the presence of big-cores via "ibm, thread-groups" > 7241d26e8175 powerpc/64: properly initialise the stackprotector canary on SMP. > > > It only happens on a specific Power9 machine, not in sim, but it's 100% > reproducible on that hardware. > > The canary value has changed (?!). > > The value in paca->canary and current->canary agree, but they don't > match what's in the stack. > > Clearly the idle code is doing something I don't understand :) Did something actually corrupt the stack? Segher