From nobody Sat Feb 7 21:14:56 2026 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 F336336BCF0 for ; Mon, 2 Feb 2026 14:41:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770043322; cv=none; b=liTthsuBFtxfQyW2YQXiQH1m0bsGab2zXwhUDcvtrRkmWnB0E7G6/t9GzilJHCjklsLnhVKgY/FYlg0Gu+eadc8xRlKQEobDXVqX+iwMyQl4cjWKYpTtAIWYIW3+Uua0jfkBK9+e0lvwxI2anSW07hAcjcUxUrU+nVJ1sLW+DAs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770043322; c=relaxed/simple; bh=OLINK77zLE0/2024ngE2NugH7GfEov5zMrEa2nfiX7E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=svHyYap+Q/ivR+Im/q1yY0Y7Lxv4LUlmwNBQL6voVCZXwero+6x799U53Wa1UsxwLgqHypfDmGCaziijNS3PuZ/xruq6Py52R21ZOzf8sAAL+BCz4Iq8LNOG2pms8M/hYdMzXSIGxYEeNuXcAukEwYiGkVLL+HwVXM1AjlWWAec= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=atLp7tqg; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="atLp7tqg" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1770043316; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2l5Tnb3N0v3njCJOSctRwBXm4lpCrQLco3FHnGD3tAk=; b=atLp7tqgCAmMtgGk1WqLqnyQRy2z0xAsHBkkXKum28ArjtNJvHjZ84p81Oqa6okkTOKfUR 40sSO0NiX/FDI1GUZK3EYNrBqKtwwOyLEsEguauCA5jH2E0vj9m2BThap/D5hcV0Sk6dv4 eUg+zyrrKRvtXVAOJ4Zi2C0wAMm88R0= From: Leon Hwang To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Christian Brauner , Seth Forshee , Yuichiro Tsuji , Andrey Albershteyn , Leon Hwang , Willem de Bruijn , Jason Xing , Tao Chen , Mykyta Yatsenko , Kumar Kartikeya Dwivedi , Anton Protopopov , Amery Hung , Rong Tao , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-patches-bot@fb.com Subject: [PATCH bpf-next v9 3/9] bpf: Refactor reporting log_true_size for prog_load Date: Mon, 2 Feb 2026 22:40:40 +0800 Message-ID: <20260202144046.30651-4-leon.hwang@linux.dev> In-Reply-To: <20260202144046.30651-1-leon.hwang@linux.dev> References: <20260202144046.30651-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" The next commit will add support for reporting logs via extended common attributes, including 'log_true_size'. To prepare for that, refactor the 'log_true_size' reporting logic by introducing a new struct bpf_log_attr to encapsulate log-related behavior: * bpf_prog_load_log_attr_init(): initialize the log fields, which will support extended common attributes in the next commit. * bpf_log_attr_finalize(): handle log finalization and write back 'log_true_size' to userspace. Signed-off-by: Leon Hwang --- include/linux/bpf.h | 4 +++- include/linux/bpf_verifier.h | 10 ++++++++++ kernel/bpf/log.c | 35 +++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 8 +++++--- kernel/bpf/verifier.c | 13 +++---------- 5 files changed, 56 insertions(+), 14 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index cd9b96434904..d4dbcc7ad156 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2913,7 +2913,9 @@ int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t e= xpected_size, size_t actual_size); =20 /* verify correctness of eBPF program */ -int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, = u32 uattr_size); +struct bpf_log_attr; +int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, + struct bpf_log_attr *attr_log); =20 #ifndef CONFIG_BPF_JIT_ALWAYS_ON void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth); diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 8355b585cd18..c805b85b6f7a 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -631,6 +631,16 @@ static inline bool bpf_verifier_log_needed(const struc= t bpf_verifier_log *log) return log && log->level; } =20 +struct bpf_log_attr { + u32 offsetof_true_size; + u32 uattr_size; + bpfptr_t uattr; +}; + +int bpf_prog_load_log_attr_init(struct bpf_log_attr *attr_log, union bpf_a= ttr *attr, + bpfptr_t uattr, u32 size); +int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_l= og *log); + #define BPF_MAX_SUBPROGS 256 =20 struct bpf_subprog_arg_info { diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index a0c3b35de2ce..ff579fcba36f 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -863,3 +863,38 @@ void print_insn_state(struct bpf_verifier_env *env, co= nst struct bpf_verifier_st } print_verifier_state(env, vstate, frameno, false); } + +static void bpf_log_attr_init(struct bpf_log_attr *attr_log, int offsetof_= true_size, bpfptr_t uattr, + u32 uattr_size) +{ + memset(attr_log, 0, sizeof(*attr_log)); + attr_log->offsetof_true_size =3D offsetof_true_size; + attr_log->uattr_size =3D uattr_size; + attr_log->uattr =3D uattr; +} + +int bpf_prog_load_log_attr_init(struct bpf_log_attr *attr_log, union bpf_a= ttr *attr, + bpfptr_t uattr, u32 size) +{ + bpf_log_attr_init(attr_log, offsetof(union bpf_attr, log_true_size), uatt= r, size); + return 0; +} + +int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_l= og *log) +{ + u32 log_true_size; + size_t size; + int err; + + if (!log) + return 0; + + err =3D bpf_vlog_finalize(log, &log_true_size); + + size =3D sizeof(log_true_size); + if (attr->uattr_size >=3D attr->offsetof_true_size + size && + copy_to_bpfptr_offset(attr->uattr, attr->offsetof_true_size, &log_tru= e_size, size)) + err =3D -EFAULT; + + return err; +} diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a58b16735e86..e81199361241 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2860,7 +2860,7 @@ static int bpf_prog_mark_insn_arrays_ready(struct bpf= _prog *prog) /* last field in 'union bpf_attr' used by this command */ #define BPF_PROG_LOAD_LAST_FIELD keyring_id =20 -static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_s= ize) +static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, struct bpf_= log_attr *attr_log) { enum bpf_prog_type type =3D attr->prog_type; struct bpf_prog *prog, *dst_prog =3D NULL; @@ -3078,7 +3078,7 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr= _t uattr, u32 uattr_size) goto free_prog_sec; =20 /* run eBPF verifier */ - err =3D bpf_check(&prog, attr, uattr, uattr_size); + err =3D bpf_check(&prog, attr, uattr, attr_log); if (err < 0) goto free_used_maps; =20 @@ -6180,6 +6180,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr= , unsigned int size, bpfptr_t uattr_common, unsigned int size_common) { struct bpf_common_attr attr_common; + struct bpf_log_attr attr_log; union bpf_attr attr; int err; =20 @@ -6231,7 +6232,8 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr= , unsigned int size, err =3D map_freeze(&attr); break; case BPF_PROG_LOAD: - err =3D bpf_prog_load(&attr, uattr, size); + err =3D bpf_prog_load_log_attr_init(&attr_log, &attr, uattr, size); + err =3D err ?: bpf_prog_load(&attr, uattr, &attr_log); break; case BPF_OBJ_PIN: err =3D bpf_obj_pin(&attr); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6b62b6d57175..1489867671e0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -25604,12 +25604,12 @@ static int compute_scc(struct bpf_verifier_env *e= nv) return err; } =20 -int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr= , __u32 uattr_size) +int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, + struct bpf_log_attr *attr_log) { u64 start_time =3D ktime_get_ns(); struct bpf_verifier_env *env; int i, len, ret =3D -EINVAL, err; - u32 log_true_size; bool is_priv; =20 BTF_TYPE_EMIT(enum bpf_features); @@ -25808,17 +25808,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_a= ttr *attr, bpfptr_t uattr, __u3 env->prog->aux->verified_insns =3D env->insn_processed; =20 /* preserve original error even if log finalization is successful */ - err =3D bpf_vlog_finalize(&env->log, &log_true_size); + err =3D bpf_log_attr_finalize(attr_log, &env->log); if (err) ret =3D err; =20 - if (uattr_size >=3D offsetofend(union bpf_attr, log_true_size) && - copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size), - &log_true_size, sizeof(log_true_size))) { - ret =3D -EFAULT; - goto err_release_maps; - } - if (ret) goto err_release_maps; =20 --=20 2.52.0