From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) (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 4BBC8219313; Thu, 19 Jun 2025 10:19:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750328387; cv=none; b=qlQif2iZgFhsh6qjFZ59eSbcXCgCZVDaFMPza0rZ3/sPxavJWir62VAoeGInmmkknQqCdlXGciaxj7u5Qj5dm6HRcWXXSnXyKzbOt5QvnZtR+FghjbuYY9tbqulaGTkz/SImBcrl3yFeuKDikhf+2kzsIJmpHQYJpXBKIc2TQ84= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750328387; c=relaxed/simple; bh=uQpmKJcQa3jBiyQsVs7DbKF/c71PSRaAxJgyqI1jUlc=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=NsUNcHNsYyoUUcGmITdPreM5RdH/TCUu5JCRJItH4xsAyQ3CJD819jFKf33XHpn1kv4EyXQ4KN4YATNjTk3cXPyc1FsnvrGijrC7RqdjLSdQNmV+/pB22sRKtlOeQtLjL3bzhDFPU9mU6+FjSlnRoLC+749a7BkW96Kb5Qeey48= 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=216.40.44.10 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 omf05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id BCC0B1D6FBB; Thu, 19 Jun 2025 10:19:41 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf05.hostedemail.com (Postfix) with ESMTPA id D459E2000D; Thu, 19 Jun 2025 10:19:36 +0000 (UTC) Date: Thu, 19 Jun 2025 06:19:28 -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: <20250619094505.GC1613376@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> <80DBA3D8-5B52-43DB-8234-EAC51D0FC0E1@goodmis.org> <20250619094505.GC1613376@noisy.programming.kicks-ass.net> Message-ID: <66A7F6C1-3693-4F76-A513-7CBBE3154B06@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-Queue-Id: D459E2000D X-Stat-Signature: rxft1uw1rdfn3xzxfp9smhq4zoupegsz X-Rspamd-Server: rspamout05 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19xJoYPE0er2ykcY2JEewGtd3aTP/uPG1s= X-HE-Tag: 1750328376-968138 X-HE-Meta: U2FsdGVkX18lITO42vyn34nmUSpJ97ltbSkNmlsjkVJLW5p7rI+wja5UcqQ3e8Yeclt7U10twAE8flO4jSkwyv73xTFcTJL6tyi2/EHSb1KqG0jrWBXTtPQAcKt95Qh/ZF/2f5FDt/0rAhAfoPgjbhB+SE2GQLjnIsnnUpagLjqsl6dVq3TvoIsX/lHbL/hMbYCUNzdGe6gyHCEZtVz9AEkU64ixxZToL/PDHFNWMRojp1PkWYExOomeJOVxZD+deTJuK7r7z80dP6pj2t5lX36HnMKnh2CrLAWR/AvvbA+tKHgyrfuj9AlDic5Mag4x+12FWJWmkEEPLTl0UB77E/D+rqf0TNKap/JQKxOlPK4/mkA5lbqiHhQfrI0BOnbKamGxNYn28tfAdTRoAPzfhg== On June 19, 2025 5:45:05 AM EDT, Peter Zijlstra w= rote: >On Thu, Jun 19, 2025 at 05:42:31AM -0400, Steven Rostedt wrote: >>=20 >>=20 >> On June 19, 2025 5:32:26 AM EDT, Peter Zijlstra wrote: >> >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 h= andle 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 >>=20 >> We probably can implement this with stacked counters=2E > >I would seriously consider dropping support for anything that can't do >cmpxchg at the width you need=2E That may be something we can do as it's a new feature and unlike the ftrac= e ring buffer, it won't be a regression not to support them=2E We currently care about x86-64, arm64, ppc 64 and s390=2E I'm assuming the= y all have a proper 64 bit cmpxchg=2E -- Steve=20