From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BB2861D95A3 for ; Wed, 8 Oct 2025 11:19:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759922371; cv=none; b=Fp9gHu3eTlJul0+HcOQaL+q2/cF/me3WXPMjhLOTX8HtPhYhc7QxTIQEU/vmvKPA/gVss81gDpXOEE5wVse3jAKfcdPDWa9tgEi6xSbrn+bIyK+SjGT95tclP0EbLspM4nqt4Ez1lFmVUcdzIiMNZdv7PzYc77H0PoMPFc50DEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759922371; c=relaxed/simple; bh=yqm9uziGZRLVLkTR7mGhsq0j/8l9Hgkqke8/vTtrqvI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o9ut5ilp/9nieJpvbDBmHQnZOC1fddvCdBkmpQzp90Uh8VMjVdEQGnj4gBHoxx1igsdx9zCn+acOXh+sd7j2I3pkB77jiaCklma7gxJqi1nUURPqMwIpb/eY8LmpxNiSYhajte/gnTXp78TIVBnER/vv5rqd0UFVMdX2j5M1y6E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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.