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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A0A1C433E0 for ; Wed, 29 Jul 2020 17:48:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F40692082E for ; Wed, 29 Jul 2020 17:48:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Vw4wTblo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726502AbgG2RsN (ORCPT ); Wed, 29 Jul 2020 13:48:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726385AbgG2RsN (ORCPT ); Wed, 29 Jul 2020 13:48:13 -0400 Received: from mail-qv1-xf42.google.com (mail-qv1-xf42.google.com [IPv6:2607:f8b0:4864:20::f42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D2A0C061794; Wed, 29 Jul 2020 10:48:13 -0700 (PDT) Received: by mail-qv1-xf42.google.com with SMTP id ed14so11267025qvb.2; Wed, 29 Jul 2020 10:48:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KLov+zHRwCIC5dmTzJG4jUY2DEz0vF5YAWPCuEXipCY=; b=Vw4wTblo7xPLb8AX+1v0epllbl48lPuFT40OiUuie6YFtL/leiZoCcDQHoh4CU0yAz y38+K1sdewtCyhgla+hqRJVVQtLdDiNexi69yCXIyevEaxkSyopHQITX1rb7KC+0LsbH 3htCk3sq4+JqwSl/xuJYSutVMy1jxgLRj27R748PFC/8Nhdako2CXXWadOQIEPUtYRoS tq+DSGjTiiF3fnlKcbh9cnE9f/g05B3DfRcGWX4Ry2Y3JVZkXd3FbJkdz0NgXUrxWsFe QdFlKPGCj/yZWK4jMsYyF4L++oaZneceEtXyp8g+3THWqOdlsDx9P5SX8wsv9di+4mc6 DHQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KLov+zHRwCIC5dmTzJG4jUY2DEz0vF5YAWPCuEXipCY=; b=furOzCggikVMiHf/i9OV02zQTKEd4WpCNPjgXdQxbwfqpOJC4DuwN3aT+dnNcNlCUE UmgU/4Zk8clJ5mB7RsarBNFMZ9NK2yDkLQyoX4XUjI/omgH1z2bZd8h/bx/c35DEVzuK dK+l0khr3exsqe2bhfeXN4lwS65Ue25q8uqYJAaA4iE62bHTFuHtYkabkYlJu+QMdbQF 2IHSeh6F8p6O5/oqcxDkB7BYjKIHYZ0c2usPdTpWf/LglZw31vLE13VxkoRO/7UsitaC s0tsTypARuXhZnzKRZU/Y0HUbnBx7NvicuP5p5V7JaN5stp94mumfIU0uCHA1soH2kgC vkBA== X-Gm-Message-State: AOAM530SV9CpVuwdTuHclX1Et8Rw4MpbHhzLcJPlqdyl0kBoiR2BhnEf pasURzg/fTVICBGsh4kpSv+egENlSjrGmKND5gU= X-Google-Smtp-Source: ABdhPJzdYOC78Mao1Zvw7purKveWY01VJjJxxKFefer0drau5rKfTQFnz1rDzot0Em+BMTnuo85l3SOeaNdYkBP54W4= X-Received: by 2002:a0c:bf4f:: with SMTP id b15mr31968009qvj.224.1596044892184; Wed, 29 Jul 2020 10:48:12 -0700 (PDT) MIME-Version: 1.0 References: <20200729040913.2815687-1-andriin@fb.com> <20200729040913.2815687-2-andriin@fb.com> <87k0ymwg2b.fsf@cloudflare.com> In-Reply-To: <87k0ymwg2b.fsf@cloudflare.com> From: Andrii Nakryiko Date: Wed, 29 Jul 2020 10:48:01 -0700 Message-ID: Subject: Re: [PATCH v4 bpf 2/2] selftests/bpf: extend map-in-map selftest to detect memory leaks To: Jakub Sitnicki Cc: Andrii Nakryiko , bpf , Networking , Alexei Starovoitov , Daniel Borkmann , Kernel Team , Song Liu , linux- stable Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Jul 29, 2020 at 7:29 AM Jakub Sitnicki wrote: > > On Wed, Jul 29, 2020 at 06:09 AM CEST, Andrii Nakryiko wrote: > > Add test validating that all inner maps are released properly after skeleton > > is destroyed. To ensure determinism, trigger kernel-side synchronize_rcu() > > before checking map existence by their IDs. > > > > Acked-by: Song Liu > > Signed-off-by: Andrii Nakryiko > > --- > > .../selftests/bpf/prog_tests/btf_map_in_map.c | 124 ++++++++++++++++-- > > 1 file changed, 110 insertions(+), 14 deletions(-) > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c > > index f7ee8fa377ad..f6eee3fb933c 100644 > > --- a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c > > +++ b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c > > @@ -5,10 +5,60 @@ > > > > #include "test_btf_map_in_map.skel.h" > > > > +static int duration; > > + > > +static __u32 bpf_map_id(struct bpf_map *map) > > +{ > > + struct bpf_map_info info; > > + __u32 info_len = sizeof(info); > > + int err; > > + > > + memset(&info, 0, info_len); > > + err = bpf_obj_get_info_by_fd(bpf_map__fd(map), &info, &info_len); > > + if (err) > > + return 0; > > + return info.id; > > +} > > + > > +/* > > + * Trigger synchronize_cpu() in kernel. > > Nit: synchronize_*r*cu(). welp, yeah > > > + * > > + * ARRAY_OF_MAPS/HASH_OF_MAPS lookup/update operations trigger > > + * synchronize_rcu(), if looking up/updating non-NULL element. Use this fact > > + * to trigger synchronize_cpu(): create map-in-map, create a trivial ARRAY > > + * map, update map-in-map with ARRAY inner map. Then cleanup. At the end, at > > + * least one synchronize_rcu() would be called. > > + */ > > That's a cool trick. I'm a bit confused by "looking up/updating non-NULL > element". It looks like you're updating an element that is NULL/unset in > the code below. What am I missing? I was basically trying to say that it has to be a successful lookup or update. For lookup that means looking up non-NULL (existing) entry. For update -- setting valid inner map FD. Not sure fixing this and typo above is worth it to post v5. > > > +static int kern_sync_rcu(void) > > +{ > > + int inner_map_fd, outer_map_fd, err, zero = 0; > > + > > + inner_map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 4, 1, 0); > > + if (CHECK(inner_map_fd < 0, "inner_map_create", "failed %d\n", -errno)) > > + return -1; > > + > > + outer_map_fd = bpf_create_map_in_map(BPF_MAP_TYPE_ARRAY_OF_MAPS, NULL, > > + sizeof(int), inner_map_fd, 1, 0); > > + if (CHECK(outer_map_fd < 0, "outer_map_create", "failed %d\n", -errno)) { > > + close(inner_map_fd); > > + return -1; > > + } > > + > > + err = bpf_map_update_elem(outer_map_fd, &zero, &inner_map_fd, 0); > > + if (err) > > + err = -errno; > > + CHECK(err, "outer_map_update", "failed %d\n", err); > > + close(inner_map_fd); > > + close(outer_map_fd); > > + return err; > > +} > > + [...] trimming's good ;)