From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (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 C9C5630EF72; Wed, 14 Jan 2026 12:37:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768394266; cv=none; b=H12Ir2+odVEHIoTS1btHN457qgenzt6Ixhl/kenBnpN2Ip6mtbsenbspjg9GCOE4bakv4C6ybpVDPPnsAiV9FiLLn/sV259vW9OT07QkayMRyyI3QBILCst9tgKhz9dfEeq+0PJY+4GRbzVqMzBXrVIETtzfaDNbv7Ekb/Zuoks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768394266; c=relaxed/simple; bh=ivImLx0IMwWptsei2EtrkPEC8sK7x+WsxIR0q4hvYGs=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=CtRZTlleNl6WwUZBPDAxi6R9xb6ksnTUoyH/wMTshmzD5gfc7ZVa9mXj9RhgP1NZ5z+gyXRurdxJhnaPus+dvzDBZRrdf7gd6+9i6fItYmGFs1ahmJtvLOU5Sw4utgXv7AsvKdBlUHMc10zBL1/WoPD/tKsspkQjA7a09RJP5zo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net; spf=pass smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=iYiYgR2r; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="iYiYgR2r" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=ivImLx0IMwWptsei2EtrkPEC8sK7x+WsxIR0q4hvYGs=; t=1768394264; x=1769603864; b=iYiYgR2ryHZpfMcskwNwTD9UUy8xlKsuDRWGSCMUjJ3e7Gl T0y9Ce8CVLzBgSrTxfgvtpdWSVmuSTBWSYDJbQ3uzRI5BubzjNxbzNtHxim4X4p4r4epcwV8nAmgw pnlehIdfDbsGsZYmhTXqPZ4A4uuTLch9S5yBwGZtJaWRV5k5NjY91/YLqysj/LZ8XB6zGQDSmNx1z 1hKUflBDfk+qnqaf0j+CpKHI6LhZlyXlxHktkKIVJcRFm9x5ZvpqL4fpC2fB22cgbA17dj377XeOI 1JDBQ0VcWk/ihr2vwJrjNQab7ZQLUSvZ7Q+csgCxvU8g1L+ejaUDPHzkitRLvHdg==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98.2) (envelope-from ) id 1vg07s-0000000Be2H-0lg3; Wed, 14 Jan 2026 13:37:28 +0100 Message-ID: <27c35b1f39c4cfaaf3b8322bbeb793c268fe4b6e.camel@sipsolutions.net> Subject: Re: [PATCH v4 0/6] KFuzzTest: a new kernel fuzzing framework From: Johannes Berg To: Ethan Graham , glider@google.com Cc: akpm@linux-foundation.org, andreyknvl@gmail.com, andy@kernel.org, andy.shevchenko@gmail.com, brauner@kernel.org, brendan.higgins@linux.dev, davem@davemloft.net, davidgow@google.com, dhowells@redhat.com, dvyukov@google.com, ebiggers@kernel.org, elver@google.com, gregkh@linuxfoundation.org, herbert@gondor.apana.org.au, ignat@cloudflare.com, jack@suse.cz, jannh@google.com, kasan-dev@googlegroups.com, kees@kernel.org, kunit-dev@googlegroups.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lukas@wunner.de, mcgrof@kernel.org, shuah@kernel.org, sj@kernel.org, skhan@linuxfoundation.org, tarasmadan@google.com, wentaoz5@illinois.edu, raemoar63@gmail.com Date: Wed, 14 Jan 2026 13:37:26 +0100 In-Reply-To: (sfid-20260114_132852_914833_479AECE9) References: <20260112192827.25989-1-ethan.w.s.graham@gmail.com> (sfid-20260114_132852_914833_479AECE9) Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-malware-bazaar: not-scanned Hi Ethan, > I wanted to check if this v4 aligns with your previous feedback regarding > the tight coupling with userspace tools. >=20 > The custom serialization has been removed entirely along with the bridge > tool. This series now focuses exclusively on passing raw binary inputs > via debugfs with the FUZZ_TEST_SIMPLE macro. >=20 > The decoupling eliminates any dependency on syzkaller and should help > remove some of the blockers that you previously encountered when > considering integration with other fuzzing engines. >=20 > Does this simplified design look closer to what you need? Thanks for reaching out! We're doing some changes here and I also need to focus on some WiFi features, so I don't really know when (if?) I'll continue working on this, but yes, this definitely aligns much better with what I had in mind. FWIW, maybe for new people on the thread, last time I was considering building ARCH=3Dum in a way that it would run into a (selectable) fuzz test, fork, and then feed it fuzzer input coming from honggfuzz [1]. I'm handwaving a bit [2], but this would basically bypass userspace completely and let us fuzz any of the tests in the kernel with "reset" for each fuzzing round. [1] selected because it's compatible with what the kernel does now with kcov for coverage feedback, afl++ currently cannot deal with this for some reason [2] because I hadn't quite figured out how to make UML a single thread only and get rid of the userspace running inside of it Regardless, definitely yes, I think the design is much simpler and even if I don't end up integrating honggfuzz this specific way, I do believe it will make it much simpler (and more performant) to integrate with other fuzzers. johannes