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 2587BC433E0 for ; Wed, 27 Jan 2021 17:04:56 +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 B6D3D64DC2 for ; Wed, 27 Jan 2021 17:04:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6D3D64DC2 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:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4lwMlXwKbryypulMw7jGaveFAPn6chLBq5RDIC3LNC8=; b=CvWZGgpB9O9F79O3Bwrmy2WPV nJRlPLAhw31LkbTStlGMbq06M4ipFeuK8G/d0jjoZ29D5sFqKsFgrS/dTfKxmu93T60bYYpSbuK/W AnE5Lbs4vQ38wFifIrberl3J3pODWmX72d2pl0ZjsWQaJQKkA7DaVMimogiJ5Jz84gUfc5gtGtrgV UEMqba6v/IIVHFhxuHqGaan5vRD8kNG1d3J/7bjyE4tYse39eZ7g7z9InLkw5jz6aqU9BD+u2LVTJ MueTgZvhmV7qORPKID0GyXjoYFlgj9GuCoJ+GZYlasRZDJ1OTNtM0F0fjxzPGAWWXDuTYy1RRq6F7 N7lkzrv9w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4mmn-0002Ou-Db; Wed, 27 Jan 2021 15:31:13 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l4mlg-0007Ur-Ml for linux-arm-kernel@merlin.infradead.org; Wed, 27 Jan 2021 15:30:04 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=yIN6/eVgr2hyDNYnOEPdIt4VBb6L7aW/C5jC6zz8gO8=; b=tgbKjCH0gFoZEYosFLLwmvwd71 MEHz0siQ9EDVbkICY5sODHHYLUoXFlvg8suWplxzKiMGvlRPVnl+a6pJDHLA/9Htf0FiB+5vmePfd 5qbMUMwiMJzhF2Yibi3zJ1BbV3TclnuKueFUuwXrh3FtSjZT/052/+PH917BOd2kBfylTJrgHXjCv pIqkVh002wp1PYqMbaUXU3//U6eBZ5Tba5fuysAmbltKayYvBARzQft8wai4f697vj0U2vwKLjOEG sgpvVv7dTVDYlMHmXiKkZFDNIuSqbZXkMN6yHLwfMRFgMRL9qemH5tJwUr+fqMaICL17zbYaGIyPr 9k+xoNJw==; Received: from linux.microsoft.com ([13.77.154.182]) by casper.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1l4lPw-00767R-1w for linux-arm-kernel@lists.infradead.org; Wed, 27 Jan 2021 14:03:50 +0000 Received: from [192.168.254.32] (unknown [47.187.219.45]) by linux.microsoft.com (Postfix) with ESMTPSA id 2D80820B7192; Wed, 27 Jan 2021 06:02:42 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 2D80820B7192 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1611756162; bh=yIN6/eVgr2hyDNYnOEPdIt4VBb6L7aW/C5jC6zz8gO8=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=VDjGabX3WsGCbo1P6wzsXtWn0sn+gZYkN1rs3sT7NGh7bxz86eCVFUrDKGbaq6XzG J2j1hnxL1yuD3r5PTV5W4AJAH97sP/1tpIR3+Ih/3wmITPtyVhOi38bqAmTwul0s7f Nx7xmN2J4fU2tTilKfl/3GxqrQ5EOk7UxHrX4Kkk= Subject: Re: [RFC PATCH 0/3] arm64: Implement reliable stack trace To: Mark Brown , Catalin Marinas , Will Deacon References: <20201012172605.10715-1-broonie@kernel.org> From: "Madhavan T. Venkataraman" Message-ID: <6439edfb-5d4f-cf15-0059-bf7ff3bebb5c@linux.microsoft.com> Date: Wed, 27 Jan 2021 08:02:41 -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: <20201012172605.10715-1-broonie@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210127_140350_540514_9C8C07F9 X-CRM114-Status: GOOD ( 18.81 ) 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 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? Madhavan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel