From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AACD9C25B0E for ; Mon, 15 Aug 2022 21:18:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243548AbiHOVPt (ORCPT ); Mon, 15 Aug 2022 17:15:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348007AbiHOVH4 (ORCPT ); Mon, 15 Aug 2022 17:07:56 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CA1E3C16E; Mon, 15 Aug 2022 12:17:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5AAD4B81109; Mon, 15 Aug 2022 19:17:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82C07C433C1; Mon, 15 Aug 2022 19:17:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660591059; bh=6yHQWsJK6FndKB55IeRJzI/BbMbACLOwRSgfytfxKLQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=btmFoF4S939Epcl1AymoW1AawIwtiP/7ttaJlF8zTQuOFLDhkvFbpPoDCL0BgZr73 TGs4Rk4MhXYWFSK4Dmrpo/P4ZeDD1weVN8W4VUcfboLbrhzk3ZfOY60P1kqRzsMT7x lRs/M434NjTevVQIQfuwNARjVAC6pRpqJUTTxbl8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anquan Wu , Andrii Nakryiko , Sasha Levin Subject: [PATCH 5.18 0458/1095] libbpf: Fix the name of a reused map Date: Mon, 15 Aug 2022 19:57:37 +0200 Message-Id: <20220815180448.543475078@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anquan Wu [ Upstream commit bf3f00378524adae16628cbadbd11ba7211863bb ] BPF map name is limited to BPF_OBJ_NAME_LEN. A map name is defined as being longer than BPF_OBJ_NAME_LEN, it will be truncated to BPF_OBJ_NAME_LEN when a userspace program calls libbpf to create the map. A pinned map also generates a path in the /sys. If the previous program wanted to reuse the map， it can not get bpf_map by name, because the name of the map is only partially the same as the name which get from pinned path. The syscall information below show that map name "process_pinned_map" is truncated to "process_pinned_". bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/process_pinned_map", bpf_fd=0, file_flags=0}, 144) = -1 ENOENT (No such file or directory) bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=4, value_size=4,max_entries=1024, map_flags=0, inner_map_fd=0, map_name="process_pinned_",map_ifindex=0, btf_fd=3, btf_key_type_id=6, btf_value_type_id=10,btf_vmlinux_value_type_id=0}, 72) = 4 This patch check that if the name of pinned map are the same as the actual name for the first (BPF_OBJ_NAME_LEN - 1), bpf map still uses the name which is included in bpf object. Fixes: 26736eb9a483 ("tools: libbpf: allow map reuse") Signed-off-by: Anquan Wu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/OSZP286MB1725CEA1C95C5CB8E7CCC53FB8869@OSZP286MB1725.JPNP286.PROD.OUTLOOK.COM Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 881ea905ca81..2323d3e38a8e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4271,7 +4271,7 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info) int bpf_map__reuse_fd(struct bpf_map *map, int fd) { struct bpf_map_info info = {}; - __u32 len = sizeof(info); + __u32 len = sizeof(info), name_len; int new_fd, err; char *new_name; @@ -4281,7 +4281,12 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) if (err) return libbpf_err(err); - new_name = strdup(info.name); + name_len = strlen(info.name); + if (name_len == BPF_OBJ_NAME_LEN - 1 && strncmp(map->name, info.name, name_len) == 0) + new_name = strdup(map->name); + else + new_name = strdup(info.name); + if (!new_name) return libbpf_err(-errno); -- 2.35.1