From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.1 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793403268; b=K1TNvWBXR/n8MR/U8mNkkZe2gH1AfrTrJdez3RqQx7j2/uUmeSDCUNC4/41F2iNl1vx/ W7NwTS5ciy7+MxkUOnmFMGLR0CO/TUTpOZrnIz4+xYu9pl0tV1IIpLrMN262YjAAgcwDf mX686jDchI0aGSzEJQbSTSVDet3TuHLBXooA0GnkZf9z0JhWbkUDpz5JUfKx4ti0/NtNG SRK9NjySZUoInfqEuWUyHNhXKlHYPUPZe/G/ao/IokEzvupxiu0kUfwuR8kVZwyQ7e7r8 pT9szD1q4m7y6wbeA2+PykiM7nRv/zawtopxW+UYFbGo8W/tEjenlrxhVnbi5/qs4oA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793403268; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=aOETFB11lK61JVpcrF0adyQknR1ZnwtVjLv9AkP3jO0=; b=4PC3a9y7eCVz1EaBS3h1mbkYdLnNh1K/CEk7wjA8SwWeWBELTGCXn2srV6gwHKGWdUIT a78tSAtWtyrfcGb7h2jkkl3mWkwBPhAO2LMmZC5kwXJuk4A+taR1frSiZNBbAAYGJxsYX GpoHSUzoTw/sTwHg1nex6Q5WbY6eyUTZI2PUUiBJ8nqLBP+MmaaHjf0BhpKup4eF6m3Fu z45O7J3sKnY4SFqI1LQTQfndAGH3THzC28Ttsbltx/u4lwDK16jAKPO2m8qRQRgfne05F V7og4fafx9GlhBkGjy82i+Ls12dsCnBL1/QJOcLpUP3GuYRAzcOXbtNb1lrH16mzHng== 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=CMeKZfQV; arc=none smtp.remote-ip=91.218.175.1 Received: from mta0.migadu.com (out-1.mta0.migadu.com [91.218.175.1]) (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 54708606A31A for ; Fri, 30 Oct 2026 23:34:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 54708606A31A 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=CMeKZfQV X-Envelope-To: bpf@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=/l7JijRqeIH4ZNLQaYcxMZRJzO7OBEldHxwLVhwg5x4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793403265; v=1; x=1794008065; b=CMeKZfQV+jm3CbX1w4BYMTDX1DAlP0m3vlgcnIoMS2HX0k94DQs9Jlg/VVs9CSnXai/xfgLp fgMoOjo3ZqHJYzrEU6GDLKZY+LZGVAGegFc58tH6nyBzScb2KQM7OzGZQw8w06U6UsfxZQYgD9w ls2+tKqW3kJxixZUIaBHpEAI= X-Envelope-To: bpf@vger.kernel.org Received: by mta12.migadu.com with ESMTPS id 32629bfefc829c4b; Fri, 30 Oct 2026 23:34:25 +0000 X-Mizu-Trace-ID: 32629bfefc829c4b X-Migadu-Flow: FLOW_OUT From: Ihor Solodrai To: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Kumar Kartikeya Dwivedi , Quentin Monnet Cc: bpf@vger.kernel.org, Alan Maguire , Cupertino Miranda , David Faust , Ian Rogers , "Jose E . Marchesi" , Vineet Gupta , Yonghong Song Subject: [PATCH bpf-next v3 04/13] bpftool: Normalize legacy arena type tags before C dumps Date: Fri, 30 Oct 2026 16:33:46 -0700 Message-ID: <20261030233355.1836749-5-ihor.solodrai@linux.dev> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261030233355.1836749-1-ihor.solodrai@linux.dev> References: <20261030233355.1836749-1-ihor.solodrai@linux.dev> 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 Content-Transfer-Encoding: 8bit Older kernel BTF encodes kflagged arena type tags as "address_space(1)". pahole emitted them since commit 21cb33c7e065 ("kbuild, bpf: Enable --btf_features=attributes"), and resolve_btfids since commit 27a78c2e7eee ("resolve_btfids: Process KF_ARENA_* flags in resolve_btfids"). Now that btf_dump prints kflagged tags as is, C dumps of such BTF declare arena kfunc pointers as "void address_space(1) *", which does not compile. Rewrite these tags to "__attribute__((address_space(1)))" in memory before dumping C. BTF without "address_space(1)" type tags stays read-only. Split BTF is dumped as is. Suggested-by: Andrii Nakryiko Signed-off-by: Ihor Solodrai --- tools/bpf/bpftool/btf.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 385521e6b028..94237befec67 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -26,6 +26,7 @@ #define KFUNC_DECL_TAG "bpf_kfunc" #define FASTCALL_DECL_TAG "bpf_fastcall" +#define LEGACY_ARENA_TAG "address_space(1)" #define MAX_ROOT_IDS 16 #define MAX_BTF_FILES 64 @@ -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; + + off = btf__add_str(btf, "__attribute__((address_space(1)))"); + if (off < 0) { + p_err("failed to rewrite legacy arena type tags: %s", strerror(-off)); + return off; + } + + for (i = 1; i < cnt; i++) { + struct btf_type *t = (struct btf_type *)btf__type_by_id(btf, i); + + if (btf_is_type_tag(t) && btf_kflag(t) && + !strcmp(btf__name_by_offset(btf, t->name_off), LEGACY_ARENA_TAG)) + t->name_off = off; + } + + return 0; +} + +static int dump_btf_c(struct btf *btf, __u32 *root_type_ids, int root_type_cnt, bool sort_dump) { struct sort_datum *datums = NULL; struct btf_dump *d; int err = 0, i; + err = btf_c_fixup_legacy_arena_tags(btf); + if (err) + return err; + d = btf_dump__new(btf, btf_dump_printf, NULL, NULL); if (!d) return -errno; -- 2.56.0