From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 719073F4DD6; Thu, 4 Jun 2026 08:41:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562503; cv=none; b=GlRiAl0hapj0+lGEH9d92eRjzoAlO1grvvlTVXxsvSx6LlkM+V14SUINsEOm/vzFmOYKoVLfV553axbZOo52NXwCuN8NZXVp7RPdIhwnHafqr4h793Za8HKnhuD3vG8+umNZrQfei38mDUXBKQ2ptFKiKmRHYwVQ+a60pi5uVjI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780562503; c=relaxed/simple; bh=YhPh9IdcFhqWCb23Ip6+9JjOw7kiI3zOhCMTEZUY4YU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Fv5WhAF02fxKUvGo35LoTHVvCVwwmuajBHmbrW0zAqOetV0vp+77hGoCjtffSBtZ3vwiCnyInAKdPYERvzNi5k7JPRRslGetMUXVuJkwLMsfXq6/XB1IB8N789RZ72QWNkqCOn6ONwxA6efGn93cy1lbNqVEE0CUZYFqSmAL3ag= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=CQ98wPYQ; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="CQ98wPYQ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=zX0Yb30KXoTmDPaFSCGyuSG5yzLZH8w2VoPpibkRoBc=; b=CQ98wPYQoIHQ1u1jztpo5I6r8j XzYvlNRbvS2OSdI3KZKnYlbvF1p7mbD3a0tHNxCEOFtHY/La7T0NtKRuVjE6Ku4qcY0cVRipJeYxQ NgfmGfcmFe6pkGxpIS38AXkbIM5vUrZSPZvwtpl2FPcFMS5y2CT35PRTHn8vAxIORLzsFkr7bK9yc 2AbfqXLQHaiH2MclpqCeZQE0RmEBdb8/U7xzJrclk6HStdm8ax3vBNt3Jf5odFNpyLMqpY9gah/jb /5CG2FyF0NZfAgw3Wv51omNe/O3dwCZs7mt5yor9BCER+U/KUwOjIOtsPuTEjf2lnhRL7k3IGwp1W +1ptFuZQ==; Received: from 2001-1c00-8d85-4b00-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:4b00:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wV3dc-00000005SJU-2IhO; Thu, 04 Jun 2026 08:41:17 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 73BF53007A4; Thu, 04 Jun 2026 10:41:15 +0200 (CEST) Date: Thu, 4 Jun 2026 10:41:15 +0200 From: Peter Zijlstra To: Yunseong Kim Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Dmitry Vyukov , Andrey Konovalov , Andrew Morton , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Nicolas Schier , Miguel Ojeda , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jonathan Corbet , Shuah Khan , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, llvm@lists.linux.dev, linux-kbuild@vger.kernel.org, rust-for-linux@vger.kernel.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, Yunseong Kim Subject: Re: [RFC PATCH v2 1/6] kcov: add per-task dataflow tracking for function arguments/return values Message-ID: <20260604084115.GZ3126523@noisy.programming.kicks-ass.net> References: <20260603-kcov-dataflow-next-20260603-v2-0-fee0939de2c4@est.tech> <20260603-kcov-dataflow-next-20260603-v2-1-fee0939de2c4@est.tech> 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=us-ascii Content-Disposition: inline In-Reply-To: <20260603-kcov-dataflow-next-20260603-v2-1-fee0939de2c4@est.tech> On Wed, Jun 03, 2026 at 07:43:28PM +0200, Yunseong Kim wrote: > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index e2f976c3301b..abd1a94589aa 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2261,6 +2261,28 @@ config KCOV_SELFTEST > On test failure, causes the kernel to panic. Recommended to be > enabled, ensuring critical functionality works as intended. > > + ^ This line... > +config KCOV_DATAFLOW_ARGS > + bool "Enable KCOV dataflow: function argument capture" > + depends on KCOV > + depends on $(cc-option,-fsanitize-coverage=dataflow-args) > + help > + Captures function arguments at entry via /sys/kernel/debug/kcov_dataflow. > + Struct pointer arguments are auto-expanded using compiler DebugInfo > + metadata, recording individual field values at runtime. > + Enable per-module with: KCOV_DATAFLOW_file.o := y in the Makefile. > + Requires clang with -fsanitize-coverage=dataflow-args support. > + > +config KCOV_DATAFLOW_RET > + bool "Enable KCOV dataflow: return value capture" > + depends on KCOV > + depends on $(cc-option,-fsanitize-coverage=dataflow-ret) > + help > + Captures function return values via /sys/kernel/debug/kcov_dataflow. > + Struct pointer returns are auto-expanded using compiler DebugInfo > + metadata, recording individual field values at runtime. > + Enable per-module with: KCOV_DATAFLOW_file.o := y in the Makefile. > + Requires clang with -fsanitize-coverage=dataflow-ret support. Probably wants to be here... > config DEBUG_AID_FOR_SYZBOT > bool "Additional debug code for syzbot" > default n > > -- > 2.43.0 >