From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59DD0405C3D for ; Wed, 27 May 2026 12:53:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779886390; cv=none; b=D75gtB066zHvVWCenf8r/4YLobEsPQZJM+fTca1MlnRiU8PzpySXcfeh8kSsGviysTE9vrZUEs/nYRLA97miWrFryDgyIwqNTR2xE5+IwYj0UmRNXhHcIpxGqmbFdxYjcXDNCDz6A8tuisasqTPtGifCGqZitAAgLRDudM2p2Zg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779886390; c=relaxed/simple; bh=SrP6SKRKlEW+kzm6E5gyWOnirxv86MAAGseQB9sR5b0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=mRwUoCCgiMKm16sydVmMJQAFyT0YhwLncsnBVe/fzcdpJtPxN99s0IiSzpidr2Hoa75iyJknKMtmlMTZgswm7zI8Dbc2RJAVNOCsnkgyV7/xa9GXZF8dWCvqz7h74pTUwISPtIPgSDLR2HrWGsrwixCXKx06EMXtDp2n08V0Ofo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--sidnayyar.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=eMligWWh; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--sidnayyar.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eMligWWh" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-48fe6894f3fso71652635e9.2 for ; Wed, 27 May 2026 05:53:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779886387; x=1780491187; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=BNY8rXPMnN6yvu32biXhw7JSMAJZadKBrhVosmLObKM=; b=eMligWWhWOdbjC9lpqGFwEz+x0Kjgt4eu/d9Mka3PQeG1gTr4z67g2MsehVEeRkUx7 NEHTApkLfrCouD4EOzaB48khadO7Zi9YlpNn8Ub7rvHtBM2qK/cSfRmU2zFEynykfih6 aX6J65UvKxVRMemoKDaFiHtK9bA8Y9S+uDEviPDhAl3fhzAWAME6SNg1BlS8zxzMrOsc N/+icIHwN+9jz1yghchoOSojiCfXOcmsjBrwL80pCXTN3Eyubv6XITtLELOSgwb9erUU hzmfHwt382R/Lw1+i51EJ+Jvt26wE7yQ0Jk4DHBRjiDrPuKmt0fdH3yVl3eyQKuOXQsK 6kqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779886387; x=1780491187; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BNY8rXPMnN6yvu32biXhw7JSMAJZadKBrhVosmLObKM=; b=NQq84i5Wk1K46J0uVPv0AlvkV0BGB5KOmXG4NUHdo9w6js/RPv6hCUp4rxDnqYU05G UQGiPkVBTX2TOPR9EzEAFpMTvTD4+ocnk3iM/bJzDp1hstWUDS4DrSoY2TSY6UIJU9XI rlWg2RV4Ojo6M639CJfSa3mERNFMv3O8SUgt3JLFfoUp8SiWbd1Lzva9eFbj6N9KB8/V JJQ/6+RBIbVMkqDsluEijbgaboDJjnQePVWrSitdHNqldtnlG5/Scs49NF2AslYPZ/JF D76IwPfktnRBd9Bbd+FyU9wME3kMUApN5ngKD8YP+OLKFZfJjN06c8sKfUHHDxNTfxwm kf3g== X-Forwarded-Encrypted: i=1; AFNElJ/rUO9uMrXbHvXIHRrnSufQ5K2ZMY7gWLG88SIZ8T8lBXa+bKudq314Rgb/oCu1qtJcPMB/4gFSzdsqodM=@vger.kernel.org X-Gm-Message-State: AOJu0YxPAzXsd0J41ihPLx+MMJA2k6Sftdr0C6gm671ES5S34YC5u60z XhI3PlDA84xqvCzimdZhcS4u4U84hUu9KCrxbejTm6COa40+e+B/pqVwaJYJHhjjda86gDtYYEm F9RE5em+HBVMDUAxyvQ== X-Received: from wmbjr17.prod.google.com ([2002:a05:600c:5611:b0:488:9407:fee8]) (user=sidnayyar job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:45c9:b0:490:5cb3:e94a with SMTP id 5b1f17b1804b1-4905cb3eb81mr247328625e9.2.1779886386321; Wed, 27 May 2026 05:53:06 -0700 (PDT) Date: Wed, 27 May 2026 12:52:59 +0000 In-Reply-To: <20260527-libbpf-load-vmlinux-btf-in-gen_loader-mode-v4-0-27daa15487a9@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260527-libbpf-load-vmlinux-btf-in-gen_loader-mode-v4-0-27daa15487a9@google.com> X-Mailer: b4 0.14.3 Message-ID: <20260527-libbpf-load-vmlinux-btf-in-gen_loader-mode-v4-3-27daa15487a9@google.com> Subject: [PATCH v4 3/3] libbpf: plumb btf_vmlinux_value_type_id and btf_fd in gen_loader From: Siddharth Nayyar To: Andrii Nakryiko , Eduard Zingerman , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi , Song Liu , Yonghong Song , Jiri Olsa Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, gprocida@google.com, maennich@google.com, Siddharth Nayyar Content-Type: text/plain; charset="utf-8" BPF `STRUCT_OPS` maps (such as `sched_ext_ops` maps) require resolving and plumbing the kernel-side structure value type ID (`btf_vmlinux_value_type_id`) into the BPF map creation system call attributes. Additionally, when `btf_vmlinux_value_type_id` is supplied, the kernel requires a valid userspace BTF file descriptor (`btf_fd`) to be supplied to verify types. Previously, the `gen_loader` map creation generator (`bpf_gen__map_create()`) omitted plumbing `btf_vmlinux_value_type_id`. Furthermore, `gen_loader.c` only copied the loaded `btf_fd` from the stack to the attributes blob if `btf_value_type_id` was non-zero. Because `STRUCT_OPS` maps explicitly zero out `btf_value_type_id`, the loader program skipped copying `btf_fd`, leaving it as `0` (standard input), which caused the kernel's `btf_get_by_fd(0)` check to fail. Fix this by: 1. Copying `btf_vmlinux_value_type_id` from the options inside `bpf_gen__map_create()`. 2. Modifying the `btf_fd` copying condition to populate `btf_fd` if either `btf_value_type_id` OR `btf_vmlinux_value_type_id` is set. Signed-off-by: Siddharth Nayyar --- tools/lib/bpf/gen_loader.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index cd5c2543f54d..a9be0c241025 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -525,13 +525,14 @@ void bpf_gen__map_create(struct bpf_gen *gen, attr.max_entries = tgt_endian(max_entries); attr.btf_key_type_id = tgt_endian(map_attr->btf_key_type_id); attr.btf_value_type_id = tgt_endian(map_attr->btf_value_type_id); + attr.btf_vmlinux_value_type_id = tgt_endian(map_attr->btf_vmlinux_value_type_id); map_create_attr = add_data(gen, &attr, attr_size); pr_debug("gen: map_create: %s idx %d type %d value_type_id %d, attr: off %d size %d\n", map_name, map_idx, map_type, map_attr->btf_value_type_id, map_create_attr, attr_size); - if (map_attr->btf_value_type_id) + if (map_attr->btf_value_type_id || map_attr->btf_vmlinux_value_type_id) /* populate union bpf_attr with btf_fd saved in the stack earlier */ move_stack2blob(gen, attr_field(map_create_attr, btf_fd), 4, stack_off(btf_fd)); -- 2.54.0.746.g67dd491aae-goog