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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4DD63CAC5BB for ; Wed, 8 Oct 2025 11:19:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=yqm9uziGZRLVLkTR7mGhsq0j/8l9Hgkqke8/vTtrqvI=; b=sJTfQO9HouVBjWsyH993JfcOPp M7ZXwLqaYi/E2vYngkMtxZNVzG7Vacoh+MaT25mIIRXuvq4tgYEKBzxrvbdio9POZBx46FA9x5jHz RFUsJa1Pqkomz9TN3KX1uAL/uNQ5PuxmNye1y1rh8pmgxpbKvP2iJXhaKtt/+Qe0gHEy5BEFa+Mr3 AIctR5kuPNecTXMlIFFGbHl/Ogk+MsmGVBPjRG5bH6Gu+efMvmD1p/28AFKOcYcd6hAZTawNmKB8B EJ/C4wcpl9g7U8kiiNNCbnG86bqagfAGuvCyvIJ+qKj+ALzi8vfjih/ahE02x4ofgj3FDk4HVqDet J6ca37nA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v6SCl-00000003hkb-26uU; Wed, 08 Oct 2025 11:19:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v6SCi-00000003hkC-0Mzh for linux-arm-kernel@lists.infradead.org; Wed, 08 Oct 2025 11:19:33 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0BE0222FC; Wed, 8 Oct 2025 04:19:21 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1DF243F66E; Wed, 8 Oct 2025 04:19:27 -0700 (PDT) Date: Wed, 8 Oct 2025 12:19:22 +0100 From: Mark Rutland To: Li Mengchen Cc: catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: kgdb: Ensure atomic single-step execution Message-ID: References: <1756972043-12854-1-git-send-email-mengchenli64@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251008_041932_172615_4DF70D67 X-CRM114-Status: GOOD ( 11.30 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Oct 08, 2025 at 09:01:22AM +0800, Li Mengchen wrote: > I am writing to address a persistent issue in the community’s code > related to single-step tracing, which has remained unresolved for over > a decade. The code I have provided has been extensively tested and > proven to work across multiple hardware platforms and kernel versions, > from 3.10 to the latest releases. Its correctness and effectiveness > are not up for debate. There is no debate; it is a statement of fact that those changes are incomplete (e.g. failing to address other asynchronous exceptions), incorrect (e.g. erroneously *unmasking* interrupts in some cases), and contain unjustified changes which are themselves incorrect (e.g. using task_pt_regs(), which *never* contains kernel register state). I appreciate that those changes may be sufficient in the scenarios that you have tested, but as I have already commented (with examples), there are real scenarios where those changes make matters worse. I agree that there are some longstanding issues here, but (as-is) the changes you have proposed are not a suitable solution. Mark.