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Wythe" X-Patchwork-Id: 13912951 X-Patchwork-Delegate: bpf@iogearbox.net Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) (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 3C446130A73; Wed, 18 Dec 2024 02:44:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734489878; cv=none; b=BD9fS04B/8rHGBiET6gQ+9IHCwU7yy35FtGmYHT61bIAJMqB+s3EcwczrDtykwo+NN+D/KM1XnVA2ZcB7BWEoKKkq/msauKAJhpuzUbcOGbvulKmBTlq4QJS8GFMUfxLT8Q3G7B84w8/3FaX2tfaPMQSsMhhn65tpbb5388D84s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734489878; c=relaxed/simple; bh=mJZToL78iwJ+MCIKU4dt4auK5Nd4QsNRcDUFMLBHKB0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=knlm0YxCWZXx2JpNK8slAWWcFoZUkL0aJ+9JomB7lzpL1DFMyiGPHERGspv6yPBmplBQuWHDY3sPuEr3gLfvpcUcN5VVPpxIPidghRhDS9e9bWGJC14Hh08ZJkzukfpUcAJE9s84dobqpO+9yzOQOpvOi58Y2ppgn8hVxvW8zOg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=uIW0khIc; arc=none smtp.client-ip=115.124.30.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="uIW0khIc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1734489872; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=y1jg5AwJB+GR83pd0hp8N7m53aNa6Qo3Q03Y+OmDbzc=; b=uIW0khIczUWE/N3efbqkpXCKSwMkoXzLXB9z5qrmZk7ikm2kS/uuR3rJXmifDZ9h6Vp71yRSbPilRpy/bFwCMh4GwN/Ig3MXYyACT6R0CpK2LmJCbD8qteBUgXeN4fzuL4GabO1QXCkytsILM1VgGq+yBVulhx6sVupHZeMFTAw= Received: from j66a10360.sqa.eu95.tbsite.net(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0WLko6em_1734489869 cluster:ay36) by smtp.aliyun-inc.com; Wed, 18 Dec 2024 10:44:30 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com, wenjia@linux.ibm.com, jaka@linux.ibm.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, pabeni@redhat.com, song@kernel.org, sdf@google.com, haoluo@google.com, yhs@fb.com, edumazet@google.com, john.fastabend@gmail.com, kpsingh@kernel.org, jolsa@kernel.org, guwen@linux.alibaba.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH bpf-next v3 4/5] libbpf: fix error when st-prefix_ops and ops from differ btf Date: Wed, 18 Dec 2024 10:44:20 +0800 Message-ID: <20241218024422.23423-5-alibuda@linux.alibaba.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20241218024422.23423-1-alibuda@linux.alibaba.com> References: <20241218024422.23423-1-alibuda@linux.alibaba.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net When a struct_ops named xxx_ops was registered by a module, and it will be used in both built-in modules and the module itself, so that the btf_type of xxx_ops will be present in btf_vmlinux instead of in btf_mod, which means that the btf_type of bpf_struct_ops_xxx_ops and xxx_ops will not be in the same btf. Here are four possible case: +--------+-------------+-------------+---------------------------------+ | | st_opx_xxx | xxx | | +--------+-------------+-------------+---------------------------------+ | case 0 | btf_vmlinux | bft_vmlinux | be used and reg only in vmlinux | +--------+-------------+-------------+---------------------------------+ | case 1 | btf_vmlinux | bpf_mod | INVALID | +--------+-------------+-------------+---------------------------------+ | case 2 | btf_mod | btf_vmlinux | reg in mod but be used both in | | | | | vmlinux and mod. | +--------+-------------+-------------+---------------------------------+ | case 3 | btf_mod | btf_mod | be used and reg only in mod | +--------+-------------+-------------+---------------------------------+ At present, cases 0, 1, and 3 can be correctly identified, because st_ops_xxx is searched from the same btf with xxx. In order to handle case 2 correctly without affecting other cases, we cannot simply change the search method for st_ops_xxx from find_btf_by_prefix_kind() to find_ksym_btf_id(), because in this way, case 1 will not be recognized anymore. To address this issue, if st_ops_xxx cannot be found in the btf with xxx and mod_btf does not exist, do find_ksym_btf_id() again to avoid such issue. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by: D. Wythe --- tools/lib/bpf/libbpf.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 66173ddb5a2d..56bf74894110 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1005,7 +1005,8 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw, const struct btf_member *kern_data_member; struct btf *btf = NULL; __s32 kern_vtype_id, kern_type_id; - char tname[256]; + char tname[256], stname[256]; + int ret; __u32 i; snprintf(tname, sizeof(tname), "%.*s", @@ -1020,17 +1021,25 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw, } kern_type = btf__type_by_id(btf, kern_type_id); + ret = snprintf(stname, sizeof(stname), "%s%s", STRUCT_OPS_VALUE_PREFIX, tname); + if (ret < 0 || ret >= sizeof(stname)) + return -ENAMETOOLONG; + /* Find the corresponding "map_value" type that will be used * in map_update(BPF_MAP_TYPE_STRUCT_OPS). For example, * find "struct bpf_struct_ops_tcp_congestion_ops" from the * btf_vmlinux. */ - kern_vtype_id = find_btf_by_prefix_kind(btf, STRUCT_OPS_VALUE_PREFIX, - tname, BTF_KIND_STRUCT); + kern_vtype_id = btf__find_by_name_kind(btf, stname, BTF_KIND_STRUCT); if (kern_vtype_id < 0) { - pr_warn("struct_ops init_kern: struct %s%s is not found in kernel BTF\n", - STRUCT_OPS_VALUE_PREFIX, tname); - return kern_vtype_id; + if (kern_vtype_id == -ENOENT && !*mod_btf) + kern_vtype_id = find_ksym_btf_id(obj, stname, BTF_KIND_STRUCT, + &btf, mod_btf); + if (kern_vtype_id < 0) { + pr_warn("struct_ops init_kern: struct %s is not found in kernel BTF\n", + stname); + return kern_vtype_id; + } } kern_vtype = btf__type_by_id(btf, kern_vtype_id); @@ -1046,8 +1055,8 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw, break; } if (i == btf_vlen(kern_vtype)) { - pr_warn("struct_ops init_kern: struct %s data is not found in struct %s%s\n", - tname, STRUCT_OPS_VALUE_PREFIX, tname); + pr_warn("struct_ops init_kern: struct %s data is not found in struct %s\n", + tname, stname); return -EINVAL; }