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bh=ivImLx0IMwWptsei2EtrkPEC8sK7x+WsxIR0q4hvYGs=; t=1768394259; x=1769603859; b=dM/LOjMqjZ2tIU+MNlUFNOcasrhF7B6TMJHgQ3DVNjFsNNW YuBwfEHZwvIKo7H/Uc9ugcxDvKZ5pbdd/nO2lsnCpC2k71ZSWZkF26pAadU7GgPd3gLVavgrvvs8+ net9yhKjTAV6bdKac263lMxtbp+K18AoAKKw8HHwCLDgsUoonu1upy68C14cN5NZFkRY4UGa5XpfL yJOxfCGELaGVqogoyLgT2QmsMra7mvzUtoRXsLGAHQxTtcvW9zZ5IVWXpgulRmWekuv14/RCoFsM4 /1IrOimLkMNZYSDsDMDStzu96I3j6TCz5Uwwf/Lb4S8gu3sArWhav3gCQuKGTW6Q==; 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) MIME-Version: 1.0 X-malware-bazaar: not-scanned X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 1DB0340007 X-Stat-Signature: g4tmgxuxr3fwwdbftenxsp541rpnahgp X-Rspam-User: X-HE-Tag: 1768394258-857452 X-HE-Meta: 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 1POl7ejB CIWumb7+hSpZ8fGZFVumU9LheuwRai7eFv53UN6Dt8JmBol5w9lq2yg//zV3M+hf2/lbPZAQAdzUCrUrBrwFbirQMRs/lYTGxFSoXc+eKO5d+YR4X4eNgIhvZA6NGAlGGZQ0mcyeWqvSFq3bfWA9bDFJJRvJ6979b1rCt2gUVwUw0bO9bFqxi4igG19mxDZnkR22nYGJiwukuvnjeu4isYD6f+YVEQloPMVAu6DF8q5Hut934Q6rQLPpW/g5FMKRWxa/jPiZWgKx0Gk9Tn5p6JB8Sxxg0d+xvDDUnRtFqghGb+HPnizoxvDVyNA== 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: 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