From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id iybdIgr8ZGQpyQwAWB0awg (envelope-from ) for ; Wed, 17 May 2023 12:08:42 -0400 Received: by simark.ca (Postfix, from userid 112) id 7AE621E11E; Wed, 17 May 2023 12:08:42 -0400 (EDT) Authentication-Results: simark.ca; dkim=pass (2048-bit key; unprotected) header.d=lists.lttng.org header.i=@lists.lttng.org header.a=rsa-sha256 header.s=default header.b=qAgWZJB4; dkim-atps=neutral X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-9.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, RCVD_IN_DNSWL_HI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Received: from lists.lttng.org (lists.lttng.org [167.114.26.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id B563B1E111 for ; Wed, 17 May 2023 12:08:41 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1684339721; bh=yZ5wqOVbSDm3R+kFIPHDbIgwGNZ15jkRiUSAJvmc3XE=; h=Date:To:References:In-Reply-To:Subject:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=qAgWZJB4GTbrYTHf53lMulwuu967rKNmd9jqyD3gaG92d1/eiPBEArM0Rgx9SCgbp ykbYOVfzPfG90l248PME5wFsL7mC1QepVO8+x9XLa/6FS9NtJCRBvH4uWXpxJQul8s lN70KNeWibYFKyHohxR9BSII4naSZfAdAPlybwX5AVtKAw7Aq9oqp1Ato2zJWWP7eO fcW7zzYjcFl3Pu1d6FsgAi7UQUvt72HimF/BMViZu34OqG09vIPFF7Swfvevw7Cy0v GvV+hNscP9psWi7ecc+1kZF9xH2AcPOJnU/h3obPO1FxwYuJZ9fNsRT1Z7wxEOhDcZ OtOfpHD3sLmJg== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4QLyhT1Zwyz1FCC; Wed, 17 May 2023 12:08:41 -0400 (EDT) Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) by lists.lttng.org (Postfix) with ESMTPS id 4QLyhR4jxXz1FCB for ; Wed, 17 May 2023 12:08:39 -0400 (EDT) Received: from [172.16.0.135] (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4QLygk6Tthz12fh; Wed, 17 May 2023 12:08:02 -0400 (EDT) Message-ID: <2d953bd2-6544-3357-1424-fa44731e2bf5@efficios.com> Date: Wed, 17 May 2023 12:08:09 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Content-Language: en-US To: Brian Hutchinson , lttng-dev@lists.lttng.org References: In-Reply-To: Subject: Re: [lttng-dev] Trying to understand use of lttng enable-event --kernel --userspace-probe= X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Mathieu Desnoyers via lttng-dev Reply-To: Mathieu Desnoyers Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" On 2023-05-16 22:11, Brian Hutchinson via lttng-dev wrote: > Hi, > > I'm trying to figure out how to use uprobes with lttng. > > I can't use a normal uprobe for a line number just using the address I > want to probe obtained from objdump? As in: > > echo 'p /usr/local/bin/my_app:0x2c3a8' >> > /sys/kernel/debug/tracing/uprobe_events > > ... which isn't a function entry, it's just a line of code I want to probe on. > > This link says it has to be elf or sdt: > https://lttng.org/man/1/lttng-enable-event/v2.11/#doc-opt--userspace-probe > > So can I not probe on just a line of code by specifying an address??? > > It doesn't look like these methods above will do what I'm wanting to > do. I've tried to find examples of using enable-event --kernel > --userspace-probe= but there doesn't appear to be many. > There are examples here: https://lttng.org/docs/v2.13/#doc-enabling-disabling-events Indeed inserting a lttng-modules uprobe within functions is not supported at the moment, mainly because we prefer to err towards safety and don't have the validation in place to prevent corrupting the program's instructions if an end user would try to insert a uprobe at an address which is not an instruction boundary. So we only support inserting uprobe on functions and SDT probes at the moment. Thanks, Mathieu > Thanks, > > Brian > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev