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Thu, 11 Sep 2025 14:26:27 -0700 (PDT) Message-ID: Subject: Re: [PATCH bpf-next v1 09/10] bpf: disable and remove registers chain based liveness From: Eduard Zingerman To: kernel test robot , bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com, yonghong.song@linux.dev Date: Thu, 11 Sep 2025 14:26:24 -0700 In-Reply-To: <202509112112.wkWw6wJW-lkp@intel.com> References: <20250911010437.2779173-10-eddyz87@gmail.com> <202509112112.wkWw6wJW-lkp@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2025-09-11 at 22:19 +0800, kernel test robot wrote: > Hi Eduard, >=20 > kernel test robot noticed the following build warnings: >=20 > [auto build test WARNING on bpf-next/master] >=20 > url: https://github.com/intel-lab-lkp/linux/commits/Eduard-Zingerman/b= pf-bpf_verifier_state-cleaned-flag-instead-of-REG_LIVE_DONE/20250911-090604 > base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git = master > patch link: https://lore.kernel.org/r/20250911010437.2779173-10-eddyz8= 7%40gmail.com > patch subject: [PATCH bpf-next v1 09/10] bpf: disable and remove register= s chain based liveness > config: x86_64-buildonly-randconfig-003-20250911 (https://download.01.org= /0day-ci/archive/20250911/202509112112.wkWw6wJW-lkp@intel.com/config) > compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0= 227cb60147a26a1eeb4fb06e3b505e9c7261) > reproduce (this is a W=3D1 build): (https://download.01.org/0day-ci/archi= ve/20250911/202509112112.wkWw6wJW-lkp@intel.com/reproduce) >=20 > If you fix the issue in a separate patch/commit (i.e. not just a new vers= ion of > the same patch/commit), kindly add following tags > > Reported-by: kernel test robot > > Closes: https://lore.kernel.org/oe-kbuild-all/202509112112.wkWw6wJW-lkp= @intel.com/ >=20 > All warnings (new ones prefixed by >>): >=20 > > > kernel/bpf/verifier.c:19305:11: warning: variable 'err' is uninitiali= zed when used here [-Wuninitialized] > 19305 | err =3D err ? : push_jmp_hist= ory(env, cur, 0, 0); > | ^~~ > kernel/bpf/verifier.c:19140:12: note: initialize the variable 'err' to= silence this warning > 19140 | int n, err, states_cnt =3D 0; > | ^ > | =3D 0 > 1 warning generated. >=20 >=20 > vim +/err +19305 kernel/bpf/verifier.c This was sloppy on my side, should look as follows: --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -19297,9 +19297,12 @@ static int is_state_visited(struct bpf_verifier_en= v *env, int insn_idx) * the precision needs to be propagated back in * the current state. */ - if (is_jmp_point(env, env->insn_idx)) - err =3D err ? : push_jmp_history(env, cur, = 0, 0); - err =3D err ? : propagate_precision(env, &sl->state= , cur, NULL); + if (is_jmp_point(env, env->insn_idx)) { + err =3D push_jmp_history(env, cur, 0, 0); + if (err) + return err; + } + err =3D propagate_precision(env, &sl->state, cur, N= ULL); if (err) return err; /* When processing iterator based loops above propa= gate_liveness and [...]