From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D28741E3DE8; Thu, 19 Jun 2025 09:42:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750326169; cv=none; b=gsUZdWvh9oib28ZrREEJD4ZSoS6PkvUgAioQtHYAowvr/hCQVj4HvzP4+Ix/GorLf5hh5g8rNbezqBJpF7nypt/ynNXvaMdmelSgCANSl+aTfwx74VDxkCfQsRS2XAvEmtfOv5rNMPvywjqd4DCO+wi9Le7DMdN5t0gMDs0e2kQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750326169; c=relaxed/simple; bh=O1jGF4Wb/pUkbNhephusfL38vZ4JQA1lxSzsxn3VAAY=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=qxwm6cuM10xfsa/SHv02Y/rV0waStEXbSvUt2CdFBf3lhRenV4D/gHlYi820kwbJhikKozY8+id9s7pmSxUlsobYJkWLA6IVFZcJKIuX7hKjCbx3G5l+hiPWfxf9DbQF8y8CSwfzbEFqfET10Pe24jpFPEmT7dK92aF5cP0V5xo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 657C310179E; Thu, 19 Jun 2025 09:42:36 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf06.hostedemail.com (Postfix) with ESMTPA id 2AABC20011; Thu, 19 Jun 2025 09:42:32 +0000 (UTC) Date: Thu, 19 Jun 2025 05:42:31 -0400 From: Steven Rostedt To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org, Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v10_07/14=5D_unwind=5Fuser/deferre?= =?US-ASCII?Q?d=3A_Make_unwind_deferral_requests_NMI-safe?= User-Agent: K-9 Mail for Android In-Reply-To: <20250619093226.GH1613200@noisy.programming.kicks-ass.net> References: <20250611005421.144238328@goodmis.org> <20250611010428.938845449@goodmis.org> <20250619085717.GB1613376@noisy.programming.kicks-ass.net> <20250619093226.GH1613200@noisy.programming.kicks-ass.net> Message-ID: <80DBA3D8-5B52-43DB-8234-EAC51D0FC0E1@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspamout01 X-Rspamd-Queue-Id: 2AABC20011 X-Stat-Signature: ebhysdh4njnmbf8en7ntwmgruebqwmcq X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18r+Rb1/p1OHbLk2qYYFtxDJr7jwhy5qnQ= X-HE-Tag: 1750326152-351886 X-HE-Meta: U2FsdGVkX18MPqMRRCSliM51ziRnLbUMZnaU3ozI0ina4JEAZ2mw9ijPZ4E8GXsAn6cT1ldjS/hTHG6T2pVNQx5YhCW4kjup0rzzC+o1BBq/ZYtKLE0QnRV3q4vrUHs+hV/vz+A2cJamMDKjVYf5zlH9L0pVeNq+bUjyDXJGjr5P/JQUctb6/w7KpWR6yvSuGjx3EFblP71hFLS2B05Vkz7CkQb5XW38J4WmjJ9Ncf+HEJV+OiAkHJiNXCmTo58xPtlRaL8jQZuIeDmti0oZdqr41xNTPbeXDOLvg4Il25ldF6oxrr4tlgEJbKxg8JGkKfLj8QPuUhA8jmLe75wIogTnRJ4kvcm8XHmsT9cKmI1x6VvRzo2x7cp5/1fxf2xDGY3vgjWD/4C80xoXeVXJ8NVwz3dO29/5KqGyjXThKEY= On June 19, 2025 5:32:26 AM EDT, Peter Zijlstra w= rote: >On Thu, Jun 19, 2025 at 05:07:10AM -0400, Steven Rostedt wrote: > >> Does #DB make in_nmi() true? If that's the case then we do need to hand= le that=2E > >Yes: #DF, #MC, #BP (int3), #DB and NMI all have in_nmi() true=2E > >Ignoring #DF because that's mostly game over, you can get them all >nested for up to 4 (you're well aware of the normal NMI recursion >crap)=2E We probably can implement this with stacked counters=2E >Then there is the SEV #VC stuff, which is also NMI like=2E So if you're a >CoCo-nut, you can perhaps get it up to 5=2E The rest of the tracing infrastructure goes 4 deep and hasn't had issues, = so 4 is probably sufficient=2E -- Steve=20