From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (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 4CEDA3FF8A9 for ; Tue, 26 May 2026 14:15:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779804945; cv=none; b=s7FuFKMDDg8TA4dCHRAVguNZrsTK0BQRuayXmFpjJz2Tc94vf/g2aVzAWV8h0/IgcmoX2QVBT7qcYnnkEK49AP6t7wzuzb/fvOoAWxPFxt4dR8K/8LEZ3KOv2wlrn9HfiQ+kPozuPFj6MKY8NmE2eSy2Fpbi+t4z2Djvwjsijjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779804945; c=relaxed/simple; bh=SrP6SKRKlEW+kzm6E5gyWOnirxv86MAAGseQB9sR5b0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=nR0ylYJ5pCEu210VaPPPnfZnom64Tvxp4cIjomy7MKEkI2SupgHBIPOvsvgyItS9btGZyH/bq4d6xwMXr1UdvHINofQgDooXd2WkSYWx97kJK1r+ipPZ+Peg9jzXQzUDICj6iFr29flIy11XUMU+yrdrwpZ3vd1Yw9b1Ljen//Q= 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=BITSzV+1; arc=none smtp.client-ip=209.85.208.74 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="BITSzV+1" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-67fd8b6631dso391945a12.2 for ; Tue, 26 May 2026 07:15:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779804940; x=1780409740; 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=BITSzV+1ZjbzjpZu5/Otr6JwbJNMpT0G1TOVnPZSqujH440tjqjjO9ultIeOevD751 K2DJY4JMX7lZWyj7vxDlxUXBtEz3+kJjRZjTCQQfCv2ro/SgBG332zX5i4ODQCVDTUUr BfFeLE6MXNHeCVJIhYLMxbtwe6PWWnZ8TwGFKo82uYI6pFbZcsPxhluHzmaf4rCGP7Ak MRpJv0yMfaf6IlBmDGc3z77gXewZxgeXNk+J84seASBP/+yEEU5GMevZgXtU9GZ3aP+T 3G5Wl3ws/EEie/p/sAocmDo/8RqLpQVR9jNvvEZuK+e38yO6FG1E/JeQ8WLDyfVCcGS7 EEsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779804940; x=1780409740; 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=YPDKRCOF0nvqZlLl8rBkGJqds7BbRnQuHzncIfyLqzmBmCpJR6y//t62t/IkeCHH4T S4BMS8U65POl55lB6zoCCPrR/97KZms8VPmdpYP4vmiTEbO1KXvd324JH0UYNafw8KQH /BdnIx2pZMoAa50oHbFef6sZ2pzgOUYF0qbctsJi1aYGR8hVA9HcdZYRhPtrr38wAqJp rZuNPJ0hmELLKokoeHdvF0ofTlz+4LKMLn3rRFX2pFIFdke7WI7exXuR71mhhtebvkCy aYxPcep/3jDXmIWvNEODI1RnKjAT5baEFDqgABwVUEf9ha2f34ChIMk26Xey9jTrmBhM OtMg== X-Forwarded-Encrypted: i=1; AFNElJ8kauEkULgmmQVLRu3zoWbLg3RxOQ+O0vKP1f0GRToa7kcKmn8SyaY0ubDAX9fjLRZvoKTO0n4L+uwOFfQ=@vger.kernel.org X-Gm-Message-State: AOJu0Ywm3ylfAeMuRBExQ+mRj0sfFbc17WBbPEMoO6J/3dHCfUX2w/nt +G/L6EQvg6kpvY3x72B1zoPx7pOS89Y6OnmuFr1JaQmvoZhqWNcQ7IESq9fsMEFxMyZAC8ODWV6 Yb7no8t+2fRj56SR9gw== X-Received: from edvt5.prod.google.com ([2002:a05:6402:205:b0:672:b7c7:1edd]) (user=sidnayyar job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:458e:b0:683:e55a:d165 with SMTP id 4fb4d7f45d1cf-6889c422dc0mr10289653a12.2.1779804940058; Tue, 26 May 2026 07:15:40 -0700 (PDT) Date: Tue, 26 May 2026 14:15:36 +0000 In-Reply-To: <20260526-libbpf-load-vmlinux-btf-in-gen_loader-mode-v3-0-5b4fa2a5e1a4@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260526-libbpf-load-vmlinux-btf-in-gen_loader-mode-v3-0-5b4fa2a5e1a4@google.com> X-Mailer: b4 0.14.3 Message-ID: <20260526-libbpf-load-vmlinux-btf-in-gen_loader-mode-v3-3-5b4fa2a5e1a4@google.com> Subject: [PATCH v3 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