From patchwork Tue Aug 1 14:26:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Hwang X-Patchwork-Id: 13336797 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 D5934C001DF for ; Tue, 1 Aug 2023 14:26:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232272AbjHAO0q (ORCPT ); Tue, 1 Aug 2023 10:26:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234655AbjHAO0o (ORCPT ); Tue, 1 Aug 2023 10:26:44 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B03A1BE3; Tue, 1 Aug 2023 07:26:44 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id d9443c01a7336-1bbc06f830aso37668425ad.0; Tue, 01 Aug 2023 07:26:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690900003; x=1691504803; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=jnJPtOd/tAS5bP3jRwz3JALotAns59ZHUtYU5AlNpuM=; b=ZGnzrX3ZoaH1ZZ13QRn9qI9/shQl5o5X2gXoWyFcjRzSbo95oytz3zedS8/SDcx8nE bEbhWiLcEKLB4ZSN11/tiQBkFbmGJNph6W5PUPkT77hv2MXpr0h8sW0sO9ynq8W3SptX tDTmloy/O+QwnEKnwIFXgfdw/4cHPmuEZiAxbX6b6ew5gOyhKTIIbMUNXGT1m44pTUHt UMfUymD0DZWmG7PpHZkZoRJsqIeRx0hjCxlRyIr2KwbX/f7YY8Ixhu9U9YxYyXNYTle/ 1+cCGU4ZR0mNPJFirVev4OSI/OFrFX7zLb6MlRZWd0jS0l1+Hxft8mVmCnDlWWk9zJIT nwBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690900003; x=1691504803; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=jnJPtOd/tAS5bP3jRwz3JALotAns59ZHUtYU5AlNpuM=; b=f4qICekWnbBhsfNsLer6ANIVa8bGcyRMIHBmI2JqtsiAEN1O6zfH+S6f0n3f0Z9vq9 ohSqCit6OkasY7wcyhe7M9s64g/LV4/L+fTYKmva+OcL04jbiO0+LpBN4zMYpx+HnSTF 0+wYKCy/Jt19yhlVtCPBaGpi7G7nK7oNpmLqToIAgcQxMoxmPodXHeW0dWicSBWHYA3r +T1jeD2CoGJGagOnY2xc4QlKsh/7sezROOf+Lf1ytuaccNpzWxA3A7LXjvUz6N+PBJv4 zqkAIcygqovt5k2ZV8ZJmhHV6Y1sQPiVutsNivJpIP8fU9M1S7K1DZ+gkqT7Z/5c5Fbe 6S6w== X-Gm-Message-State: ABy/qLZeOpgOrz2ewCMfd5wpxBMA96EnFrqUGTdJ+KVmsmIJwaLJkhU/ l+d0e2lRuioNOIgMTBWLfOA60g2s8H8XCiqz X-Google-Smtp-Source: APBJJlGp0T3bwxu11JjeJvAP/G84kaAZx5TRCf188WmCYmtolQxWAT/yq+sNvIt6U96wH4E0P87MQw== X-Received: by 2002:a17:902:ce8d:b0:1b6:6a14:3734 with SMTP id f13-20020a170902ce8d00b001b66a143734mr18267314plg.29.1690900003056; Tue, 01 Aug 2023 07:26:43 -0700 (PDT) Received: from localhost.localdomain (bb219-74-209-211.singnet.com.sg. [219.74.209.211]) by smtp.gmail.com with ESMTPSA id 6-20020a170902c10600b001b8a00d4f7asm10565100pli.9.2023.08.01.07.26.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 07:26:42 -0700 (PDT) From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, hawk@kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, mykolal@fb.com, shuah@kernel.org, hffilwlqm@gmail.com, tangyeechou@gmail.com, kernel-patches-bot@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf-next v5 1/2] bpf, xdp: Add tracepoint to xdp attaching failure Date: Tue, 1 Aug 2023 22:26:20 +0800 Message-ID: <20230801142621.7925-2-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230801142621.7925-1-hffilwlqm@gmail.com> References: <20230801142621.7925-1-hffilwlqm@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When error happens in dev_xdp_attach(), it should have a way to tell users the error message like the netlink approach. To avoid breaking uapi, adding a tracepoint in bpf_xdp_link_attach() is an appropriate way to notify users the error message. Hence, bpf libraries are able to retrieve the error message by this tracepoint, and then report the error message to users. Signed-off-by: Leon Hwang --- include/trace/events/xdp.h | 17 +++++++++++++++++ net/core/dev.c | 5 ++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h index c40fc97f94171..cd89f1d5ce7b8 100644 --- a/include/trace/events/xdp.h +++ b/include/trace/events/xdp.h @@ -404,6 +404,23 @@ TRACE_EVENT(mem_return_failed, ) ); +TRACE_EVENT(bpf_xdp_link_attach_failed, + + TP_PROTO(const char *msg), + + TP_ARGS(msg), + + TP_STRUCT__entry( + __string(msg, msg) + ), + + TP_fast_assign( + __assign_str(msg, msg); + ), + + TP_printk("errmsg=%s", __get_str(msg)) +); + #endif /* _TRACE_XDP_H */ #include diff --git a/net/core/dev.c b/net/core/dev.c index 8e7d0cb540cdb..002fec07de739 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -133,6 +133,7 @@ #include #include #include +#include #include #include #include @@ -9470,6 +9471,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct net *net = current->nsproxy->net_ns; struct bpf_link_primer link_primer; + struct netlink_ext_ack extack = {}; struct bpf_xdp_link *link; struct net_device *dev; int err, fd; @@ -9497,12 +9499,13 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) goto unlock; } - err = dev_xdp_attach_link(dev, NULL, link); + err = dev_xdp_attach_link(dev, &extack, link); rtnl_unlock(); if (err) { link->dev = NULL; bpf_link_cleanup(&link_primer); + trace_bpf_xdp_link_attach_failed(extack._msg); goto out_put_dev; } From patchwork Tue Aug 1 14:26:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Hwang X-Patchwork-Id: 13336798 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 7900EC001E0 for ; Tue, 1 Aug 2023 14:26:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234660AbjHAO04 (ORCPT ); Tue, 1 Aug 2023 10:26:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234655AbjHAO0w (ORCPT ); Tue, 1 Aug 2023 10:26:52 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D703E1FC6; Tue, 1 Aug 2023 07:26:49 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id d9443c01a7336-1bb775625e2so37517725ad.1; Tue, 01 Aug 2023 07:26:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690900009; x=1691504809; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=sU+jnsfF3qd3Nicz0CmetjFrKuzZhIcjZbK3uCZNd0U=; b=WtYp1UWv6iwV0u/y76mh23hRQ+a0MNn6Pn38CQD4z6ZZc4/RZxkex9OVflI/6/Ct7i tqKkDxwKY2WWtL/mMlKIV9zttLYSrHnaFZwvtuxDP5hFImvSTU0cdSnztu2dKJP5xGHt 1kqbBnDmY7V+QTrQI6QV7/V9Qv9zLQA0Umxj2TksIqEL7mOAXMwEKGwNbZevm4r/h8Wc J6P3DRglIt0aPVkH1obSgi1Nioaw0Aa6vj/HmhFvIefVdkDrQsdzQbUbCCQZDMCg4U9V XLnlWUHsI69ow/9XGw3K0/tlQ2uwZsuiy+Sb9DSDzMBhvlsTWNeMm8UoGB/RSUum3nce nrzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690900009; x=1691504809; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=sU+jnsfF3qd3Nicz0CmetjFrKuzZhIcjZbK3uCZNd0U=; b=egwOrjpkg1uUZXXDjvs/uG1Nia3005wkoh07VYpKe9Zc0llc/vqxiX9jpAHKv+vv/q J2h5WNLPgOvvTr4W3wvkAGMUpXcvvfGCcj3/MKf1/FtyWwtSP9TZ3SX4XkOQfi04Oyjt OWP3i7driF72rumn9BZdB/ORBNzeVM8MK2OT+KGrDYiH2s8BY4vsQzipHvTVjx9XnUjr Exb4ANIc0JzCCdqgQ2AE/JM0Sz/YwJPugW7CQxKJYEPaZKptIfjcS2xCCQWn4DPcEFYq 1+ts1pvxl5n+OmAxdusFLS2wIzkYKx5ZehH5mSZSEkT3zXEVbISnVQZLJ6jAGOKmyCVv uJDw== X-Gm-Message-State: ABy/qLY2HAyxW2yjGDuUXp1JZzu4gYz3q8O3nwtPBWP563dxNRcfN2qi xXukMNYAIx22XCGJT06VsEfwSrC/cRiHHYn8 X-Google-Smtp-Source: APBJJlGXWNmDSziieGkGGouNt5Btt4C/CtFHJdxcZK3q6fe/xi8wEMStSsy7be02mHeJq8nBSocA1w== X-Received: by 2002:a17:902:ce83:b0:1bc:17ab:8d68 with SMTP id f3-20020a170902ce8300b001bc17ab8d68mr7037501plg.16.1690900008864; Tue, 01 Aug 2023 07:26:48 -0700 (PDT) Received: from localhost.localdomain (bb219-74-209-211.singnet.com.sg. [219.74.209.211]) by smtp.gmail.com with ESMTPSA id 6-20020a170902c10600b001b8a00d4f7asm10565100pli.9.2023.08.01.07.26.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 07:26:48 -0700 (PDT) From: Leon Hwang To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, hawk@kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, mykolal@fb.com, shuah@kernel.org, hffilwlqm@gmail.com, tangyeechou@gmail.com, kernel-patches-bot@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf-next v5 2/2] selftests/bpf: Add testcase for xdp attaching failure tracepoint Date: Tue, 1 Aug 2023 22:26:21 +0800 Message-ID: <20230801142621.7925-3-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230801142621.7925-1-hffilwlqm@gmail.com> References: <20230801142621.7925-1-hffilwlqm@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Add a test case for the tracepoint of xdp attaching failure by bpf tracepoint when attach XDP to a device with invalid flags option. The bpf tracepoint retrieves error message from the tracepoint, and then put the error message to a perf buffer. The testing code receives error message from perf buffer, and then ASSERT "Invalid XDP flags for BPF link attachment". Signed-off-by: Leon Hwang --- .../selftests/bpf/prog_tests/xdp_attach.c | 65 +++++++++++++++++++ .../bpf/progs/test_xdp_attach_fail.c | 54 +++++++++++++++ 2 files changed, 119 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c index fa3cac5488f5d..e6bcb6051402d 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include +#include "test_xdp_attach_fail.skel.h" #define IFINDEX_LO 1 #define XDP_FLAGS_REPLACE (1U << 4) @@ -85,10 +86,74 @@ static void test_xdp_attach(const char *file) bpf_object__close(obj1); } +#define ERRMSG_LEN 64 + +struct xdp_errmsg { + char msg[ERRMSG_LEN]; +}; + +static void on_xdp_errmsg(void *ctx, int cpu, void *data, __u32 size) +{ + struct xdp_errmsg *ctx_errmg = ctx, *tp_errmsg = data; + + memcpy(&ctx_errmg->msg, &tp_errmsg->msg, ERRMSG_LEN); +} + +static const char tgt_errmsg[] = "Invalid XDP flags for BPF link attachment"; + +static void test_xdp_attach_fail(const char *file) +{ + struct test_xdp_attach_fail *skel = NULL; + struct xdp_errmsg errmsg = {}; + struct perf_buffer *pb = NULL; + struct bpf_object *obj = NULL; + int err, fd_xdp; + + LIBBPF_OPTS(bpf_link_create_opts, opts); + + skel = test_xdp_attach_fail__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_xdp_attach_fail__open_and_load")) + goto out_close; + + err = test_xdp_attach_fail__attach(skel); + if (!ASSERT_EQ(err, 0, "test_xdp_attach_fail__attach")) + goto out_close; + + /* set up perf buffer */ + pb = perf_buffer__new(bpf_map__fd(skel->maps.xdp_errmsg_pb), 1, + on_xdp_errmsg, NULL, &errmsg, NULL); + if (!ASSERT_OK_PTR(pb, "perf_buffer__new")) + goto out_close; + + err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &fd_xdp); + if (!ASSERT_EQ(err, 0, "bpf_prog_test_load")) + goto out_close; + + opts.flags = 0xFF; // invalid flags to fail to attach XDP prog + err = bpf_link_create(fd_xdp, IFINDEX_LO, BPF_XDP, &opts); + if (!ASSERT_EQ(err, -EINVAL, "bpf_link_create")) + goto out_close; + + /* read perf buffer */ + err = perf_buffer__poll(pb, 100); + if (!ASSERT_GT(err, -1, "perf_buffer__poll")) + goto out_close; + + ASSERT_STRNEQ((const char *) errmsg.msg, tgt_errmsg, + 42 /* strlen(tgt_errmsg) */, "check error message"); + +out_close: + perf_buffer__free(pb); + bpf_object__close(obj); + test_xdp_attach_fail__destroy(skel); +} + void serial_test_xdp_attach(void) { if (test__start_subtest("xdp_attach")) test_xdp_attach("./test_xdp.bpf.o"); if (test__start_subtest("xdp_attach_dynptr")) test_xdp_attach("./test_xdp_dynptr.bpf.o"); + if (test__start_subtest("xdp_attach_failed")) + test_xdp_attach_fail("./xdp_dummy.bpf.o"); } diff --git a/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c new file mode 100644 index 0000000000000..2ff1b596e87ea --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright Leon Hwang */ + +#include +#include + +#define ERRMSG_LEN 64 + +struct xdp_errmsg { + char msg[ERRMSG_LEN]; +}; + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __type(key, int); + __type(value, int); +} xdp_errmsg_pb SEC(".maps"); + +struct xdp_attach_error_ctx { + unsigned long unused; + + /* + * bpf does not support tracepoint __data_loc directly. + * + * Actually, this field is a 32 bit integer whose value encodes + * information on where to find the actual data. The first 2 bytes is + * the size of the data. The last 2 bytes is the offset from the start + * of the tracepoint struct where the data begins. + * -- https://github.com/iovisor/bpftrace/pull/1542 + */ + __u32 msg; // __data_loc char[] msg; +}; + +/* + * Catch the error message at the tracepoint. + */ + +SEC("tp/xdp/bpf_xdp_link_attach_failed") +int tp__xdp__bpf_xdp_link_attach_failed(struct xdp_attach_error_ctx *ctx) +{ + char *msg = (void *)(__u64) ((void *) ctx + (__u16) ctx->msg); + struct xdp_errmsg errmsg = {}; + + bpf_probe_read_kernel_str(&errmsg.msg, ERRMSG_LEN, msg); + bpf_perf_event_output(ctx, &xdp_errmsg_pb, BPF_F_CURRENT_CPU, &errmsg, + ERRMSG_LEN); + return 0; +} + +/* + * Reuse the XDP program in xdp_dummy.c. + */ + +char LICENSE[] SEC("license") = "GPL";