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=unavailable 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 64538C433E6 for ; Mon, 31 Aug 2020 12:46:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3625C206E3 for ; Mon, 31 Aug 2020 12:46:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598877974; bh=xpciEiK1NwSQDebvBUt8PqEJ0Povb15SzOC+Y7MqoZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DE0AGnoUaolX1rpR9FusGJnJEWcHtI9cIbKlVeTDEi5Z9i72ME/c38URXHVjLAUZ7 s+BiEarRWpbW+ixeWO8+i9gURRQAnrvPBDARGoY2S4oQb0Mm/DE41Z7MS9DVYmGMNR cgtawuP5eOgZ1EWuqgKhicakDv8r/pOpSw4FehgQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727931AbgHaMqM (ORCPT ); Mon, 31 Aug 2020 08:46:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:47094 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbgHaMqF (ORCPT ); Mon, 31 Aug 2020 08:46:05 -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 CCC7F20936; Mon, 31 Aug 2020 12:46:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598877965; bh=xpciEiK1NwSQDebvBUt8PqEJ0Povb15SzOC+Y7MqoZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tm0X0Bnskgtx626aIhezv8tq7tulaFU3a02p5jY8yCe97ApiLEIeMVX4lpuYoRS9S aIo2O9kvct12CyFJvs6hK2BD66CXX8xM57Zb8O8hqh1FvH0+zp2K68OTBsN6T/t1Sg nwbU9+gYaddTY/+CoLhEyShzLNIQJpwhyBL4b9XA= From: Masami Hiramatsu To: Steven Rostedt , Jonathan Corbet Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH 4/6] tracing/kprobes: Support perf-style return probe Date: Mon, 31 Aug 2020 21:46:01 +0900 Message-Id: <159887796151.1330989.2690618021941671783.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <159887792384.1330989.5993224243767476896.stgit@devnote2> References: <159887792384.1330989.5993224243767476896.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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)) {