From patchwork Mon Jan 9 09:42:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Menglong Dong X-Patchwork-Id: 40753 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:4e01:0:0:0:0:0 with SMTP id p1csp2063171wrt; Mon, 9 Jan 2023 01:47:34 -0800 (PST) X-Google-Smtp-Source: AMrXdXtedpxWuvWtzTccMZNQoJ0hwUaZJ2FD/jO++dfIAhHxQbjtk4HviQlkcLRFc5UFVuF3jLNG X-Received: by 2002:a17:906:60cd:b0:845:bb21:f638 with SMTP id f13-20020a17090660cd00b00845bb21f638mr50567924ejk.75.1673257654078; Mon, 09 Jan 2023 01:47:34 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1673257654; cv=none; d=google.com; s=arc-20160816; b=PHV1qMgJfzhfs20kzbNpjXwEFwHXKfdoMmTQZpTRD+I39pj2rifzZH6Qcyahy4sAQN 8KRH5Df4IdqYIOfke+vgbYj77skPiwrMaRINC32vgR79J8y38ZyH0D6NohSdDKhABq9L 347cIaPwdHoj/ODPLWnvRBbA7ihSfRcD0M9T+zJHRlbduEqhjn3x8wvFCIkY9oHAw/A8 CBH8qsllGiPdbVaJf08VBpG90K63PRp+d9kqJXV3wlVwH8wVb+0zaTWPqZqE/EqJLsjo tYNuIOt9UzLemCqewnXesWD40LoVc/Av27Qey57qZ9sLY1m+qACZmJLYn/wRTmetfeDe IBbA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=001Ob8msDHYSJ4H6+BAMlx9g50lKceUKFFGpbLEZpGo=; b=J9zXM9sH/C9Usbvgb/H4shdn5ksBh7yHXyAQoLNyWMTKVN7Y3V4fzIVXYBwUBa9lW9 Hzh5JAqrmOpFRxJGYqTp/T+UmsMquXt8Uq18Y1dS18YTzXgAcj10dQYHFgqqrWNYAu91 CnMgz2VxOgEJxoS5VQc7dsUfLDs5UhyqH8a1P0NZ7JImjSt4cvGpOrEDnPANHS0krg/3 wuq1GSySBaDMHhyIdoF/bWYQr/2mZQzkjIcoAAQ3nfve3bKUp5hIs+N/k9nxC6xZRwj0 CdV9Y5AqrRyXtnbTGCo2DeqNFfHmfweYFq1tJdJYW55nnpXIKSCicLe58CD84YaSwLo4 8MTg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=eYDyOUaH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id wv4-20020a170907080400b007c10bb5b4b3si9307658ejb.681.2023.01.09.01.47.10; Mon, 09 Jan 2023 01:47:34 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=eYDyOUaH; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233885AbjAIJnn (ORCPT + 99 others); Mon, 9 Jan 2023 04:43:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231126AbjAIJni (ORCPT ); Mon, 9 Jan 2023 04:43:38 -0500 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 459AE1166; Mon, 9 Jan 2023 01:43:37 -0800 (PST) Received: by mail-pf1-x441.google.com with SMTP id c9so5674768pfj.5; Mon, 09 Jan 2023 01:43:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=001Ob8msDHYSJ4H6+BAMlx9g50lKceUKFFGpbLEZpGo=; b=eYDyOUaHHTHcueKILaSCYIfEciTW1pbEIlEDRLZdc9Ld42Fi2TMY/zFOiUclIOYxKE G3/Vdt+ep3en4CD1mF1VzlSKuo+Wh9HxpkvfD9ZxyfG2pUc4J+5QBSTBaqsv0puA5093 Qu9WF+zTU+e/LwbJOmsbes/c0YUi3NyINImEReG2kovWz6Wvfh0NfJoHTvzal72OKPmz 61xy1Eh8diyfbUQbVjVt0GljfAvO+xDSAPx4ODJJMHsDZZYuir01obzwfCabdj6JAyF/ WE5/hm2vf1huqC9lEba3pNmbEHqaTcg3Xwj/ovuUgF8h08W+FGa52hgsIdz66aXOjA+L EozA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=001Ob8msDHYSJ4H6+BAMlx9g50lKceUKFFGpbLEZpGo=; b=4ls3ZSJ89YHmWAiBGRBfdptqdECbkarkPa3NlYFCtG2ZZoK9v4YlSR9iShIrnrNq6I bG9bbKWiwnvSk4UkwK1gVR0E3sJDbc3a/3z/mmnzSbcGyUqPeu9D1BctoCxe3f0Fwi+C mvp+KHqRC1ox2K2QArXmboobn5qLbA0Kb+zzkua4KcgS+YtW5ms75bcvi4vw+dFPotzC VnoZQ0dKmfnrdHFDBnZ2KLhnIiOvR2sKKB7rUUmmqZ28DrcKXKeNXc8cQlD4NHJ+jq4g FMNS4xPwCl8EGa/KduPloI7Ti7ycPmA7DzNmlndKQ0WS7PgnB00oDnwgZiR4iW4omC1D SnDw== X-Gm-Message-State: AFqh2kpC8eJd7vRq+/rxBhO7ARCWWJG8AEbAXcSXuta/jxGfaAljlfoY kU3EaIL0HQ7HIZ04ys6Ukrw= X-Received: by 2002:a05:6a00:414c:b0:581:7c46:debd with SMTP id bv12-20020a056a00414c00b005817c46debdmr44941706pfb.24.1673257416708; Mon, 09 Jan 2023 01:43:36 -0800 (PST) Received: from localhost.localdomain ([203.205.141.20]) by smtp.gmail.com with ESMTPSA id z8-20020aa79e48000000b00580849b55a2sm5629527pfq.26.2023.01.09.01.43.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Jan 2023 01:43:36 -0800 (PST) From: menglong8.dong@gmail.com X-Google-Original-From: imagedong@tencent.com To: daniel@iogearbox.net Cc: ast@kernel.org, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Menglong Dong Subject: [PATCH] libbpf: resolve kernel function name optimization for kprobe Date: Mon, 9 Jan 2023 17:42:47 +0800 Message-Id: <20230109094247.1464856-1-imagedong@tencent.com> X-Mailer: git-send-email 2.39.0 MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1754537817815539995?= X-GMAIL-MSGID: =?utf-8?q?1754537817815539995?= From: Menglong Dong The function name in kernel may be changed by the compiler. For example, the function 'ip_rcv_core' can be compiled to 'ip_rcv_core.isra.0'. This kind optimization can happen in any kernel function. Therefor, we should conside this case. If we failed to attach kprobe with a '-ENOENT', then we can lookup the kallsyms and check if there is a similar function end with '.xxx', and retry. Signed-off-by: Menglong Dong --- tools/lib/bpf/libbpf.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a5c67a3c93c5..fdfb1ca34ced 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10375,12 +10375,30 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, return libbpf_err_ptr(err); } +struct kprobe_resolve { + char pattern[128]; + char name[128]; +}; + +static int kprobe_kallsyms_cb(unsigned long long sym_addr, char sym_type, + const char *sym_name, void *ctx) +{ + struct kprobe_resolve *res = ctx; + + if (!glob_match(sym_name, res->pattern)) + return 0; + strcpy(res->name, sym_name); + return 1; +} + static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) { DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts); + struct kprobe_resolve res = {}; unsigned long offset = 0; const char *func_name; char *func; + int err; int n; *link = NULL; @@ -10408,8 +10426,25 @@ static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf opts.offset = offset; *link = bpf_program__attach_kprobe_opts(prog, func, &opts); + err = libbpf_get_error(*link); + + if (!err || err != -ENOENT) + goto out; + + sprintf(res.pattern, "%s.*", func); + if (!libbpf_kallsyms_parse(kprobe_kallsyms_cb, &res)) + goto out; + + pr_warn("prog '%s': trying to create %s '%s+0x%zx' perf event instead\n", + prog->name, opts.retprobe ? "kretprobe" : "kprobe", + res.name, offset); + + *link = bpf_program__attach_kprobe_opts(prog, res.name, &opts); + err = libbpf_get_error(*link); + +out: free(func); - return libbpf_get_error(*link); + return err; } static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link)