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Fri, 30 Oct 2026 04:52:46 -0700 (PDT) Received: from [127.0.1.1] ([23.254.208.9]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1ac1abcd6f1sm6437304c88.20.2026.10.30.04.52.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Oct 2026 04:52:45 -0700 (PDT) From: Qiliang Yuan Date: Fri, 30 Oct 2026 07:51:53 -0400 Subject: [PATCH bpf-next v2 08/22] bpf: Remove dead code through the patch list X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261030-bpf-verifier-patch-batch-v2-8-55cd43439f7c@gmail.com> References: <20261030-bpf-verifier-patch-batch-v2-0-55cd43439f7c@gmail.com> In-Reply-To: <20261030-bpf-verifier-patch-batch-v2-0-55cd43439f7c@gmail.com> To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Qiliang Yuan X-Mailer: b4 0.13.0 bpf_opt_remove_dead_code() removes every range of instructions that the verifier never reached with verifier_remove_insns(). Each removal moves the tail of the program and of its aux data and walks all of it, so a program with many unreached ranges pays O(prog->len) for each of them. Queue the removal of each unreached instruction with bpf_patch_list_del() and commit them once. Signed-off-by: Qiliang Yuan --- kernel/bpf/fixups.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/kernel/bpf/fixups.c b/kernel/bpf/fixups.c index 1a1a374a076b1..95f4fe5d607e6 100644 --- a/kernel/bpf/fixups.c +++ b/kernel/bpf/fixups.c @@ -1018,21 +1018,14 @@ int bpf_opt_remove_dead_code(struct bpf_verifier_env *env) keep_funcs_with_addr_taken(env); for (i = 0; i < insn_cnt; i++) { - int j; - - j = 0; - while (i + j < insn_cnt && !aux_data[i + j].seen) - j++; - if (!j) + if (aux_data[i].seen) continue; - - err = verifier_remove_insns(env, i, j); + err = bpf_patch_list_del(env, i); if (err) return err; - insn_cnt = env->prog->len; } - return 0; + return bpf_patch_list_commit(env); } int bpf_opt_remove_nops(struct bpf_verifier_env *env) -- 2.43.0