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 D4685C32792 for ; Tue, 23 Aug 2022 11:19:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244001AbiHWLTa (ORCPT ); Tue, 23 Aug 2022 07:19:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357522AbiHWLRk (ORCPT ); Tue, 23 Aug 2022 07:17:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5816989828; Tue, 23 Aug 2022 02:21:20 -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 dfw.source.kernel.org (Postfix) with ESMTPS id D234A60F91; Tue, 23 Aug 2022 09:21:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8B57C433D6; Tue, 23 Aug 2022 09:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246479; bh=8njpsnWF1Zh3tqoTkQO/LTe/AkDeuMCTFEDJG4ZiugQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ob/QeDKlvXDdBG5pfmRTBT44iFYWEfx638wEDdOrHzteisHB89mOzVEX/76JYNJoI OE/W64vz7sz/e23i+EFrL48rlv8d7c8WtBoO9BiMmCKl2H9eZEW+tMm0HC84nqX5lB ifNdisAkKOh2fT3KiFtAlmS7CK9BhqvF85QUC+r4= 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 5.4 123/389] libbpf: Fix the name of a reused map Date: Tue, 23 Aug 2022 10:23:21 +0200 Message-Id: <20220823080120.742141330@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@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: stable@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 2a1dbf52fc9a..b8849812449c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1884,7 +1884,7 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map) 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; @@ -1892,7 +1892,12 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) if (err) return 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 -errno; -- 2.35.1