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,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 842D5C433DB for ; Tue, 23 Mar 2021 14:17:28 +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 0F91360295 for ; Tue, 23 Mar 2021 14:17:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F91360295 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:References: Cc: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=egy0axS7QhoEa08JoHqKPatLut/pi1XywlL5BZPVep0=; b=fM3/1MT5zkuLnvxX8ei4WRglP 3Mvk/0T1cpZg1gXibwjq3XQYGO3sbQprnC9g/esgH7SymgWdqWjZ8qn4vPzCURvSr6bNxfADnn/Xo zkvrZtVFL3eWoAg7z7WQTKAV+r9wG2sf8/qaX/I+2y38c7Zv8Yk9eF1enLR7cF9A39BepazKrrkBL ljqN/hcuEj/dAfQ0rBxQhBghCtdX3a6BVnTLl6rn2p/Er77liOJEVogkpiORt7MTepMKdR/l1N9N0 8ACFh2t5ld7o7CGcruZJHLlyAxIaPT70AUy1/FBf9MBo2MvNFrwQY5r10fHEDj4nKG0PzOGVqi5jr 8BkbTp2NQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOhot-00F8nv-35; Tue, 23 Mar 2021 14:15:43 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lOhoo-00F8nA-Nn for linux-arm-kernel@lists.infradead.org; Tue, 23 Mar 2021 14:15:40 +0000 Received: from [192.168.254.32] (unknown [47.187.194.202]) by linux.microsoft.com (Postfix) with ESMTPSA id 1AB2920B5680; Tue, 23 Mar 2021 07:15:37 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1AB2920B5680 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1616508937; bh=xgH5742pf9m8cPa2AZwpL/Wba0dOvxATlNgx0Syu1uY=; h=Subject:From:To:Cc:References:Date:In-Reply-To:From; b=dd74ytk9ub/9O/tG2Uc0luCp0AuFiMdkHXYkoCQ9PD7OQmA+zDSONc2/U6D+ULydO YFRRHcUZWyDVvBOZfzqobW0AyhOCGO2uG7dwt2KIFDluc07ftHfwW9q/w9efBYr5sv MbCvwDCoI+7N+ghkk2JlZ6JpgYUnso6TdZxiS044= Subject: Re: [RFC PATCH v2 5/8] arm64: Detect an FTRACE frame and mark a stack trace unreliable From: "Madhavan T. Venkataraman" To: Mark Rutland Cc: broonie@kernel.org, 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> <20210315165800.5948-6-madvenka@linux.microsoft.com> <20210323105118.GE95840@C02TD0UTHF1T.local> <2167f3c5-e7d0-40c8-99e3-ae89ceb2d60e@linux.microsoft.com> <20210323133611.GB98545@C02TD0UTHF1T.local> Message-ID: Date: Tue, 23 Mar 2021 09:15:36 -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: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210323_141539_054358_DF2D29F1 X-CRM114-Status: UNSURE ( 7.94 ) X-CRM114-Notice: Please train this message. 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 Hi Mark, I have a general question. When exceptions are nested, how does it work? Let us consider 2 cases: 1. Exception in a page fault handler itself. In this case, I guess one more pt_regs will get established in the task stack for the second exception. 2. Exception in an interrupt handler. Here the interrupt handler is running on the IRQ stack. Will the pt_regs get created on the IRQ stack? Also, is there a maximum nesting for exceptions? Madhavan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel