From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.43 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793406689; b=gcrKAV96FNIaSgXQ3MTKXqfdzliHbhnV929SuCgjZF2Na9QH9A5Re0hLz8Lo2k0UQ3IK 95PPQIV2X1e/4hs4t9SS6ojaqo9zgadLmij1gTJZuaXYl5LswPDPd6hwiY0enXgrSQ43w pRlE5Y/5sJ9SffL7ty8lB3evkB7X3NB4UgS3xWLDHDK4XwDDPKucyO35SAyYIHe/yt0FL 8IsxUEe8ZQO5o4Ip/ATz+B6nOxRo5WO+oT7cB9LhkGpTakjKuh+d/dSxcYgJwX82+nDlW xYZugY+EdaoN9WYJX80fuAouUQSMmQNfRtgYe+8aNzErD3hXQymlmNFmv+UGLzXOP6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793406689; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:Content-Language:From:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=IXG0sxDC41P8FbPKBXtL73aMgp3ZfXzAv6aGiPAR6bc=; b=sS5wNRpqRwqj6+k/EUnDGnpdg1+/Vfdj/mqtfgm7yDRn6Y5aNJSP/jip3JIjGXVM/qhq pQCuc7vn6ZY+x5KgC98GkJlINljAkzI0+BYHFiL8dhZb+FviRj1CFqYtFv1UE0noe8Loa 0viad9uVNrz6LfPXxh71d8ZTakybyOrc4WN9FI9pRVlOBtG32x8JB4PjPBWjphe1W4Dyz yu4VRSya3LUUchvq3lRXjNvmA6aZbSsIWWp4A3QqChi4d3prx1MLsg6+LpYVIlq5udBls AvfNREBkqXwmzeLsRxcf7Gwkb8/ycPhxkLj6QA3QnNJebMA4WMGEupXNkzr0ahAoq+w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=wkoTU3My; arc=none smtp.remote-ip=95.215.58.43 Received: from mta1.migadu.com (out-43.mta1.migadu.com [95.215.58.43]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D8371606A31A for ; Sat, 31 Oct 2026 00:31:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D8371606A31A 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, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=wkoTU3My X-Envelope-To: bpf@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=e68WjUm5ypCvZVtT91GSngElSLR4dLlmdP5VBoxHKeA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793406685; v=1; x=1794011485; b=wkoTU3MyFEp4BgZUBqq/lJzxMoAprQniNvLVx818ACpUiMgIBoLAkrsXThT5VhfJM4NcH36G FO1sCE8Xp/g3bSP2tkHJDJo77FWQzaC5hA/CCU3/nrXU992EFo8LgA3S824MeH0yx0vBVuwctKL Q2OD/zM1fCY0UOeCp0RKze7Y= X-Envelope-To: bpf@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 1e9d4d40634a9526; Sat, 31 Oct 2026 00:31:25 +0000 X-Mizu-Trace-ID: 1e9d4d40634a9526 X-Migadu-Flow: FLOW_OUT Message-ID: <18b21d29-8cf8-42de-b5b0-92ccd5783a75@linux.dev> Date: Fri, 30 Oct 2026 17:31:20 -0700 X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v3 04/13] bpftool: Normalize legacy arena type tags before C dumps To: bot+bpf-ci@kernel.org, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, memxor@gmail.com, qmo@kernel.org Cc: bpf@vger.kernel.org, alan.maguire@oracle.com, cupertino.miranda@oracle.com, david.faust@oss.qualcomm.com, irogers@google.com, jose.marchesi@oracle.com, vineet.gupta@linux.dev, yonghong.song@linux.dev, martin.lau@kernel.org, mason@kernel.org References: <20261030233355.1836749-5-ihor.solodrai@linux.dev> <3c1960998302f1ac50394163cf62ccf59ad088c0f586512a5d7771c95ec7e3f2@mail.kernel.org> Content-Language: en-US From: Ihor Solodrai In-Reply-To: <3c1960998302f1ac50394163cf62ccf59ad088c0f586512a5d7771c95ec7e3f2@mail.kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/30/26 5:16 PM, bot+bpf-ci@kernel.org wrote: >> bpftool: Normalize legacy arena type tags before C dumps > > TL;DR: The legacy arena tag fixup skips split BTF, so module C dumps on older > kernels may still print "address_space(1)" for vmlinux arena kfuncs and fail > to compile; commit message doesn't say so. > >> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c >> --- a/tools/bpf/bpftool/btf.c >> +++ b/tools/bpf/bpftool/btf.c > > [ ... ] > >> @@ -1092,13 +1093,47 @@ static struct sort_datum *sort_btf_c(const struct btf *btf) >> return datums; >> } >> >> -static int dump_btf_c(const struct btf *btf, >> +/* >> + * Older kernel BTF encodes kflagged arena type tags as "address_space(1)", >> + * which btf_dump prints as is. Rewrite them to the complete specifier. >> + */ >> +static int btf_c_fixup_legacy_arena_tags(struct btf *btf) >> +{ >> + __u32 i, cnt = btf__type_cnt(btf); >> + int off; >> + >> + if (btf__base_btf(btf) || >> + btf__find_by_name_kind(btf, LEGACY_ARENA_TAG, BTF_KIND_TYPE_TAG) < 0) >> + return 0; > > Can this early return for split BTF leave module C dumps broken on older > kernels? Yes, it will. That's intentional: the fixup targets only vmlinux BTF, which is always the base. I don't know of any users relying on btf C dump for modules, but if there are any they are advised to re-compile their modules with updated resolve_btfids to use a new format. > > [...]