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=-10.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 D4E18C433E9 for ; Wed, 27 Jan 2021 17:25:54 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 7D0DB64DA6 for ; Wed, 27 Jan 2021 17:25:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D0DB64DA6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:References: To:From:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FfDor9Pma0UlkiBVnG7wiMMMC4iaI68Hf+2uDib/7gs=; b=dfjYpGDhleSvpY52syP/DArU8 Ftyzn+ytwCArYiLsechgzfi3wiZ2v0k1PfS8trM1i8fEOdgT9sP6+2HYkkFl6Ol/+R4xv5LvMfDEh eE71LXFtjySAtKyLngE6J1QTe7Cujth2zKVLYig14X2bCkG7MyyrVb/0XWXAk6MGwNXCbB1bay+Co U1G8HLb2+fEoU1+xXDDMkC2MAHd9t9dBOP2o/pKEao420lrwFpHSqalOpZSvawu9DPLIPxlGCE43+ iq7pK9fu/U2y+31hv33MITyCRZP2Hto/NcQoYwJGxN7TBEIH9pskJn/guBxzr84bzBSiYHEGsq5Ae C+Kd9jfhQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4oYh-00058f-Ns; Wed, 27 Jan 2021 17:24:47 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4oYf-000585-Vb for linux-arm-kernel@lists.infradead.org; Wed, 27 Jan 2021 17:24:46 +0000 Received: from [192.168.254.32] (unknown [47.187.219.45]) by linux.microsoft.com (Postfix) with ESMTPSA id 564A820B6C40; Wed, 27 Jan 2021 09:24:44 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 564A820B6C40 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1611768284; bh=9//yx5SoKeuXtJvMhuHC/oGWiU9dzQa8vl8FgM1t6RI=; h=Subject:From:To:Cc:References:Date:In-Reply-To:From; b=lG7eQ8Buv0+MLjbJuPfbOa/QDgERKlIfxFZfSEjxFK1WGvdwSaHGCZmDfiV3axITB qLFySLKbOHnFjyb4USq3DJpLuFD+vBKfyU8m0R9scEZENTYuBciiUmrWqnhsODkhhv KtLFTIPqlEoj9uqOHZj4Gr3V1l5BpBkNusPjyxVQ= Subject: Re: [RFC PATCH 0/3] arm64: Implement reliable stack trace From: "Madhavan T. Venkataraman" To: Mark Brown , Catalin Marinas , Will Deacon References: <20201012172605.10715-1-broonie@kernel.org> <6439edfb-5d4f-cf15-0059-bf7ff3bebb5c@linux.microsoft.com> Message-ID: <63e6b1fc-b2c9-000e-d766-995d20a2a364@linux.microsoft.com> Date: Wed, 27 Jan 2021 11:24:43 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <6439edfb-5d4f-cf15-0059-bf7ff3bebb5c@linux.microsoft.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210127_122446_092762_0D924BCF X-CRM114-Status: GOOD ( 21.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Miroslav Benes , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/27/21 8:02 AM, Madhavan T. Venkataraman wrote: > > > On 10/12/20 12:26 PM, Mark Brown wrote: >> This patch series aims to implement reliable stacktrace for arm64. >> Reliable stacktrace exists mainly to support live patching, it provides >> a version of stacktrace that checks for consistency problems in the >> traces it generates and provides an error code to callers indicating if >> any problems were detected. >> >> This is a first cut of support for arm64, I've not really even started >> testing it meaningfully at this point. The main thing I'm looking for >> here is that I'm not sure if there are any more potential indicators of >> unrelabile stacks that I'm missing tests for or anything about the >> interfaces that I've misunderstood. >> >> There's more work that can be done here, mainly that we could sync our >> unwinder more with what's done on S/390 and x86 which should if nothing >> else help with keeping up to date with generic changes, but this should >> be what's needed to allow reliable stack trace. >> >> Mark Brown (2): >> arm64: stacktrace: Report when we reach the end of the stack >> arm64: stacktrace: Implement reliable stacktrace >> >> Mark Rutland (1): >> arm64: remove EL0 exception frame record >> >> arch/arm64/Kconfig | 1 + >> arch/arm64/kernel/entry.S | 10 +++---- >> arch/arm64/kernel/stacktrace.c | 55 ++++++++++++++++++++++++++++------ >> 3 files changed, 52 insertions(+), 14 deletions(-) >> > > This is mostly a question to improve my understanding of the current ARM64 > unwinder. > > Currently, ARM64 defines different stack types - task stack, IRQ stack, etc. > When it unwinds, it appears to unwind only the currently active stack. > Specifically, if an interrupt has happened and the IRQ stack is the one that > is active, only the IRQ stack is unwound. The task stack is not. Is this > accurate? > > My question is - for live patching, we would need to look at the task stack > as well, right? May be, we need to pass a flag to the unwinder to check the > task stack in addition to the active task? Typo - I meant to say "active stack" at the end of the question. Sorry about that. Madhavan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel