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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 78531C433E6 for ; Tue, 1 Sep 2020 07:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 444492098B for ; Tue, 1 Sep 2020 07:57:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598947036; bh=xpciEiK1NwSQDebvBUt8PqEJ0Povb15SzOC+Y7MqoZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lU4DRunjWLCAf+nuSOTH/KR3sOayS9Rfaq3OlPqDVCofYcEG7lb7o/VBAJpicKmQW T7YBJhC2iIVHsEpBkAJyoXRR//js4u6Yo7++Gfq7PCggZzt2URkrt8XyfS0HjGJZHF QGnfslj9PEk5uqH8cjJ40TX3gKQgWbp4T65HfCfI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727883AbgIAH5P (ORCPT ); Tue, 1 Sep 2020 03:57:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:53082 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726044AbgIAH5P (ORCPT ); Tue, 1 Sep 2020 03:57:15 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2C9B72065F; Tue, 1 Sep 2020 07:57:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598947035; bh=xpciEiK1NwSQDebvBUt8PqEJ0Povb15SzOC+Y7MqoZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pmeUZbmsyHCSqmM8wBNNJ6HUwklakXmVlQHrTSceCEUHPpY5q/SbCYtnjnTMpVLCP RMorO/omzQq/YaZlhaY6SqU921Av/0TUXMcun/DdMVqbAtIoEDCFVa0CuVbfT0lAIg PAFqMBcHbjx96OJPgx7PxktqzzXpm7sa9jd9KAJY= From: Masami Hiramatsu To: Steven Rostedt , Jonathan Corbet Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Randy Dunlap , Ingo Molnar Subject: [PATCH v2 4/6] tracing/kprobes: Support perf-style return probe Date: Tue, 1 Sep 2020 16:57:10 +0900 Message-Id: <159894703070.1478826.15755889933157654537.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <159894698993.1478826.2813843560314595660.stgit@devnote2> References: <159894698993.1478826.2813843560314595660.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Support perf-style return probe ("SYMBOL%return") in kprobe events. This will allow boot-time tracing user to define a return probe event. Signed-off-by: Masami Hiramatsu --- kernel/trace/trace_kprobe.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index aefb6065b508..391361b67c8f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -709,6 +709,18 @@ static inline void sanitize_event_name(char *name) *name = '_'; } +static inline bool split_return_suffix(char *symbol) +{ + char *p = strchr(symbol, '%'); + + if (p && !strcmp(p, "%return")) { + *p = '\0'; + return true; + } + + return false; +} + static int trace_kprobe_create(int argc, const char *argv[]) { /* @@ -717,6 +729,9 @@ static int trace_kprobe_create(int argc, const char *argv[]) * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] + * Or + * p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS] + * * Fetch args: * $retval : fetch return value * $stack : fetch stack address @@ -746,7 +761,6 @@ static int trace_kprobe_create(int argc, const char *argv[]) switch (argv[0][0]) { case 'r': is_return = true; - flags |= TPARG_FL_RETURN; break; case 'p': break; @@ -804,12 +818,17 @@ static int trace_kprobe_create(int argc, const char *argv[]) symbol = kstrdup(argv[1], GFP_KERNEL); if (!symbol) return -ENOMEM; + + is_return = split_return_suffix(symbol) || is_return; + /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); if (ret || offset < 0 || offset > UINT_MAX) { trace_probe_log_err(0, BAD_PROBE_ADDR); goto parse_error; } + if (is_return) + flags |= TPARG_FL_RETURN; if (kprobe_on_func_entry(NULL, symbol, offset)) flags |= TPARG_FL_FENTRY; if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {