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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AF24ACAC59A for ; Thu, 18 Sep 2025 16:04:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1A4528E0107; Thu, 18 Sep 2025 12:04:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 17CEA8E00F6; Thu, 18 Sep 2025 12:04:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 092288E0107; Thu, 18 Sep 2025 12:04:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id E9EBB8E00F6 for ; Thu, 18 Sep 2025 12:04:11 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 9C07B8567D for ; Thu, 18 Sep 2025 16:04:11 +0000 (UTC) X-FDA: 83902842702.19.477FB5F Received: from 003.mia.mailroute.net (003.mia.mailroute.net [199.89.3.6]) by imf08.hostedemail.com (Postfix) with ESMTP id 9B218160013 for ; Thu, 18 Sep 2025 16:04:09 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=acm.org header.s=mr01 header.b=Mf0M1J8U; spf=pass (imf08.hostedemail.com: domain of bvanassche@acm.org designates 199.89.3.6 as permitted sender) smtp.mailfrom=bvanassche@acm.org; dmarc=pass (policy=reject) header.from=acm.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758211449; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=4wzWm6RSRc1tNocFJFpFoox7GYZLGguM76hcy5QnMFw=; b=XoBkkt4zuF2M0ljRiGrqHxwUwcY5rrYCZXJGPfj1Bf61Hke2OEfYYGR5NfSjwBXIvdb1uC CQyzw0DGT2yUcjFoSr3PijX1uqSiIzBj8M39K3mQpkCWhI7vMekle9r5tmrTRKWXjVJ0J+ WCe3y3C74/wEveCdnLU+fVFEzhP1PJ4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1758211449; a=rsa-sha256; cv=none; b=eBDzU0pp12VTxrLFfMO8PkMs9OSIyaASkRxsUpzUGFVeO3tEcfBsm+WKTYg0i21F4lQTig icxD5SWsmZUQX9a6MycqJ3fSMLzGhHUxGLVPoK8P4iLNGP6oU/C/ZPH1ZmIjH3nVMKnPfs T1DRCU0JdPQh+UHaI+iwOYJD47H7dQk= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=acm.org header.s=mr01 header.b=Mf0M1J8U; spf=pass (imf08.hostedemail.com: domain of bvanassche@acm.org designates 199.89.3.6 as permitted sender) smtp.mailfrom=bvanassche@acm.org; dmarc=pass (policy=reject) header.from=acm.org Received: from localhost (localhost [127.0.0.1]) by 003.mia.mailroute.net (Postfix) with ESMTP id 4cSL6c3snqzlgn8k; Thu, 18 Sep 2025 16:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1758211439; x=1760803440; bh=4wzWm6RSRc1tNocFJFpFoox7 GYZLGguM76hcy5QnMFw=; b=Mf0M1J8U6wTLeu2gHoc5SUiGtJ7IvGYk8UZ6fQtQ F2HzXxFsv2wJKVo3E3itBcK5M7HBPy7vs16rMQdZNtkdtlpHUdAB6gp5zElM1tQv X44SkYoj7S3blZaRVlzHiogKzJP7RsYrM9zFM9RqFriOFHgBvgFNCVmVWHjXbnfj BCNxjhZ/nIKCSqWA5KRGlBXCj8ouY534Wu4SFzXm9YsWLm1w6mkQLx3XVjEv5N0J qYICjPTqTk8g9G9tSYHje0mRJLCaVRl0Qo98o58MrF9E6yTEcWnwOiMsYBacC9iZ WV8PxWTT8jpLUWJ3lpx2TSzx7JNYmCOfRmR8oXeNulu1CA== X-Virus-Scanned: by MailRoute Received: from 003.mia.mailroute.net ([127.0.0.1]) by localhost (003.mia [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id 6L6n7UbPW0mK; Thu, 18 Sep 2025 16:03:59 +0000 (UTC) Received: from [100.66.154.22] (unknown [104.135.204.82]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 003.mia.mailroute.net (Postfix) with ESMTPSA id 4cSL5g10BTzltKG9; Thu, 18 Sep 2025 16:03:18 +0000 (UTC) Message-ID: <1ca90ba0-7bdc-43d1-af12-bba73dd3234a@acm.org> Date: Thu, 18 Sep 2025 09:03:17 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 02/35] compiler-capability-analysis: Add infrastructure for Clang's capability analysis To: Ian Rogers , Marco Elver Cc: Peter Zijlstra , Boqun Feng , Ingo Molnar , Will Deacon , "David S. Miller" , Luc Van Oostenryck , "Paul E. McKenney" , Alexander Potapenko , Arnd Bergmann , Bill Wendling , Christoph Hellwig , Dmitry Vyukov , Eric Dumazet , Frederic Weisbecker , Greg Kroah-Hartman , Herbert Xu , Jann Horn , Joel Fernandes , Jonathan Corbet , Josh Triplett , Justin Stitt , Kees Cook , Kentaro Takeda , Lukas Bulwahn , Mark Rutland , Mathieu Desnoyers , Miguel Ojeda , Nathan Chancellor , Neeraj Upadhyay , Nick Desaulniers , Steven Rostedt , Tetsuo Handa , Thomas Gleixner , Thomas Graf , Uladzislau Rezki , Waiman Long , kasan-dev@googlegroups.com, linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-sparse@vger.kernel.org, llvm@lists.linux.dev, rcu@vger.kernel.org, Steven Rostedt References: <20250918140451.1289454-1-elver@google.com> <20250918140451.1289454-3-elver@google.com> Content-Language: en-US From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 9B218160013 X-Stat-Signature: axe311uzjiwrqit5u9mncuihgkeodyzi X-Rspam-User: X-HE-Tag: 1758211449-903599 X-HE-Meta: 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 92GKCNiL 6koDXAccdlheqi5wDwAhgzaVf2/XWI1kCxAlNUzEbIDL+7Q4WWC+LcLFpu/qOJWvvynEWhR/lQTavDozjffvaJ1MEOdd2ZzvdnUufMX9xGNcqktbe4FHmfepZ+zzblbh+/gpLgklO+As0G6OQFWA7YfBSudvnS1KdudGtOSnvEBxrsJg2jPJ6GE/YyfkQ7yEwKhx+By2NQxL0xCPWUAJYqOvkbec1BpvpNauscM1EyxrWy8qogmq4v1wGC6dASusivHFI0NWxrDJYpISzKLVzw8+AlowXKzITslKXWlH1AS4zFgOQ6RPqUbP2qayY322eid117bZ35es4eVB2Ge+7yBSO9pwsX37RaCgpqwHmD6BzTCg7IspqsR/JFt+uLFRQtdc0Pges3hXoRNVS6FywXNtowdyK+XHrvoaII5Spmp88CANfxfnXfdfEeuhvk3XHIUP4 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/18/25 8:58 AM, Ian Rogers wrote: > On Thu, Sep 18, 2025 at 7:05=E2=80=AFAM Marco Elver = wrote: >> +config WARN_CAPABILITY_ANALYSIS >> + bool "Compiler capability-analysis warnings" >> + depends on CC_IS_CLANG && CLANG_VERSION >=3D 220000 >> + # Branch profiling re-defines "if", which messes with the comp= iler's >> + # ability to analyze __cond_acquires(..), resulting in false p= ositives. >> + depends on !TRACE_BRANCH_PROFILING >=20 > Err, wow! What and huh, and why? Crikes. I'm amazed you found such an > option exists. I must be very naive to have never heard of it and now > I wonder if it is needed and load bearing? (+Steven) This is an old option. I think this commit introduced it: commit 52f232cb720a7babb752849cbc2cab2d24021209 Author: Steven Rostedt Date: Wed Nov 12 00:14:40 2008 -0500 tracing: likely/unlikely branch annotation tracer Bart.