From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com [34.218.115.239]) (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 8EC123A9635; Thu, 1 Oct 2026 23:51:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=34.218.115.239 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790898692; cv=none; b=HwPVaYJgxvsJ6K1PrdltLQaSt8g886j3TYB1iGFV9YQSxKZb9mBs3cZakvmLdgPi5/VPPOj1P07ohunVNcFGK1fKox7XMtEQessYuuvF0IdYyZX3tocGdipmBR9zzjGg66/LDHPn788EPvIfnKMcQlVPS4FolYSdzwctuwNr93Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790898692; c=relaxed/simple; bh=E4SnCaFYxr6lAWkTGxym06Vo1B+vuoPzDviTpwQrMSA=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=rWk2coeJcENp9ilwqthe+FyKX97/DS2ODUOc81kzONoTyY/oCzDKvcNcyA7D2sR31yEM2C1gpsmFesH8IFCdsriSjRpK0cC9YS2rizYPLudsidWUTKprYxWcQU8oBjWmjjUNnIeXaIJp2KY1BBWB/merdKlfR4euoOSNE47f4D4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=VANaSBrd; arc=none smtp.client-ip=34.218.115.239 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="VANaSBrd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1790898689; x=1822434689; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+gakBsFf0rsEzmOYbq/bI2y9Z71TNc4ZwgCbBPMtrZw=; b=VANaSBrdorE4qxYJ8w9vWnZz8TYrjaxonWHXUFm+BGoh8wY4wHjpAHH3 ByHwxaTW5zzbAdJfhTOBWk17sT7S1wL1yTxwc6wJfDlNJUx51naMAdB8L s5TB6xczAn2wAvdWGqzDgwjiB4SkDwDOlxKjleyKDckashqe3xtWDicsU x6s24iBWbWQKt9/ctP/lDDc9+3Lhd6T5ikAFMPF+NOUh1cbt4qE+bd/I4 hAAw65qZzuL3rtDGH6LerVwHITWCehpLXmVtPg7O/2OmUFhU818LU6cDk rHZyk5xyMO93dTfq0FSWe+qjZXdmKkNy96zpjYbHfLRh85sPJf7oSoqCr g==; X-CSE-ConnectionGUID: 2n5c2uYJS5Grx2dF5YETyg== X-CSE-MsgGUID: 3bnsxS3hTqWFx6UmPgjbug== X-IronPort-AV: E=Sophos;i="6.27,135,1787011200"; d="scan'208";a="29970246" Received: from ip-10-5-12-219.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.12.219]) by internal-pdx-out-013.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2026 23:51:28 +0000 Received: from EX19MTAUWA002.ant.amazon.com [205.251.233.234:5728] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.52.137:2525] with esmtp (Farcaster) id 51a7109b-3f32-4603-95cf-00e4fb61676f; Thu, 1 Oct 2026 23:51:27 +0000 (UTC) X-Farcaster-Flow-ID: 51a7109b-3f32-4603-95cf-00e4fb61676f Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWA002.ant.amazon.com (10.250.64.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.49; Thu, 1 Oct 2026 23:51:27 +0000 Received: from dev-dsk-wanjay-2c-d25651b4.us-west-2.amazon.com (172.19.198.4) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.49; Thu, 1 Oct 2026 23:51:27 +0000 From: Jay Wang To: CC: , , , Subject: Re: [PATCH bpf-next v3 3/9] bpf: fetch the vmlinux BTF where kernel types enter a program Date: Thu, 1 Oct 2026 23:51:27 +0000 Message-ID: <20261001235127.4111-1-wanjay@amazon.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260925231100.6A2481F00893@smtp.kernel.org> References: <20260925231100.6A2481F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D040UWA003.ant.amazon.com (10.13.139.6) To EX19D001UWA001.ant.amazon.com (10.13.138.214) The scenario does not happen; v4 keeps this behaviour: https://lore.kernel.org/bpf/20261001225214.12351-1-wanjay@amazon.com/ With CONFIG_DEBUG_INFO_BTF=m an allocation failure of the parse is not stored: bpf_load_btf_vmlinux(), which parses the BTF in v4, returns the error without publishing it, btf_vmlinux stays NULL, the next request retries, and this check does not fire for anyone. What v4 does store with =m, as a later bpf-ci review asked, is a parse failure for any other reason. The payload was checked against the kernel's size and SHA-256 when btf_vmlinux.ko loaded, so that means the build produced a broken BTF. The same happens with =y, where upstream already fails every later bpf_check() with this message. With =y the parse happens at boot, through the first vmlinux kfunc registration, as it does today. Jay