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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 6BCBCC433DB for ; Thu, 18 Mar 2021 20:31:10 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 EAF1C64F30 for ; Thu, 18 Mar 2021 20:31:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAF1C64F30 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=92dQm6bFz+nx+mfPhKn8I3giV6KGvNkO+6uOvFCsY3g=; b=pI3PADLxLVNHQ4O7Zzd/7ovxw lJJKUdLfprNUjYmv/evY8sEpTjmOSpl6G0oHr2MQXaFyiP59lOeXrs05NGKZYh1lhCnrL13ay51GU xfpc5fRZRvPNYBP5FBKRxT76+PuA1KJrZ0AN1Ih6Br+PRpL0CBvqWRAs0zTHDJ6rdguCAaRC1AHYb 8Jji0rwz8blyZBqzkutJUqI6yT7SS9c/E3KYAREwRyZMQnhbI57tk3tQy2evW9JI/Ht19VRNntxpo C6M98M0/jX3E62cuK1nDwI0qtQzC3ppHpdIsxvvO+eGL0Vd9Ugu8vhTXUWPvbhdta2E1cuDyHAylh xEdN3w/9Q==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMzGn-005zbG-Q6; Thu, 18 Mar 2021 20:29:26 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMzGj-005zar-7l for linux-arm-kernel@lists.infradead.org; Thu, 18 Mar 2021 20:29:23 +0000 Received: from [192.168.254.32] (unknown [47.187.194.202]) by linux.microsoft.com (Postfix) with ESMTPSA id D6CA420B39C5; Thu, 18 Mar 2021 13:29:19 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D6CA420B39C5 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1616099360; bh=NYashDADQj5U4guXBYGYNqz58yYoc5xd3wmlNGCFhJ4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=WvyUdTts2mfk1Bx6gUPgrA0HI+h5qR0lj4zP6ln5NPlgKiOTvJ0IDP/b4qceWrr30 mnVWKgo6OAeSIZ5XaFS7CO5iNxLoZrbGY0l+N7k/A1CwAGZTFFaB6/KHrePgTSP2Ol WIGUdney3aQu7Sy585CzEDMgc/7tqk1W3eUuLlUQ= Subject: Re: [RFC PATCH v2 3/8] arm64: Terminate the stack trace at TASK_FRAME and EL0_FRAME To: Mark Brown Cc: mark.rutland@arm.com, jpoimboe@redhat.com, jthierry@redhat.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org References: <5997dfe8d261a3a543667b83c902883c1e4bd270> <20210315165800.5948-1-madvenka@linux.microsoft.com> <20210315165800.5948-4-madvenka@linux.microsoft.com> <20210318182607.GO5469@sirena.org.uk> From: "Madhavan T. Venkataraman" Message-ID: Date: Thu, 18 Mar 2021 15:29:19 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210318182607.GO5469@sirena.org.uk> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210318_202921_517201_463749EF X-CRM114-Status: GOOD ( 17.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 3/18/21 1:26 PM, Mark Brown wrote: > On Mon, Mar 15, 2021 at 11:57:55AM -0500, madvenka@linux.microsoft.com wrote: > >> + /* Terminal record, nothing to unwind */ >> + if (fp == (unsigned long) regs->stackframe) { >> + if (regs->frame_type == TASK_FRAME || >> + regs->frame_type == EL0_FRAME) >> + return -ENOENT; >> return -EINVAL; >> + } > > This is conflating the reliable stacktrace checks (which your series > will later flag up with frame->reliable) with verifying that we found > the bottom of the stack by looking for this terminal stack frame record. > For the purposes of determining if the unwinder got to the bottom of the > stack we don't care what stack type we're looking at, we just care if it > managed to walk to this defined final record. > > At the minute nothing except reliable stack trace has any intention of > checking the specific return code but it's clearer to be consistent. > So, you are saying that the type check is redundant. OK. I will remove it and just return -ENOENT on reaching the final record. Madhavan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel