From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754508AbcIUDiM (ORCPT <rfc822;w@1wt.eu>);
        Tue, 20 Sep 2016 23:38:12 -0400
Received: from mail.kernel.org ([198.145.29.136]:52822 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1753724AbcIUDiK (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 20 Sep 2016 23:38:10 -0400
Date: Wed, 21 Sep 2016 12:37:59 +0900
From: Masami Hiramatsu <mhiramat@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
        David Ahern <dsahern@gmail.com>
Subject: Re: failed to add c++ probe
Message-Id: <20160921123759.5c3f1f5db5f298a20ea784b0@kernel.org>
In-Reply-To: <alpine.DEB.2.20.1609200129550.5524@nanos>
References: <20160919095402.GA2306@krava>
        <20160920080557.5db69ddd16524ca6abcb3d83@kernel.org>
        <alpine.DEB.2.20.1609200129550.5524@nanos>
X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, 20 Sep 2016 01:32:04 +0200 (CEST)
Thomas Gleixner <tglx@linutronix.de> wrote:

> Masami,
> 
> On Tue, 20 Sep 2016, Masami Hiramatsu wrote:
> > Hmm, could you try to find mangled symbol from the library as below?
> > 
> > ./perf probe -x /usr/lib64/libstdc++.so.6 -F \*
> > 
> > And also try to do adding probe with -v option again?
> > 
> > In my case, I could find the mangled symbol, but failed to setup the probe...
> 
> ./perf probe -x /usr/lib/x86_64-linux-gnu/libstdc++.so.6 -v _X_ZNKSt13basic_fstreamIcSt11char_traitsIcEE7is_openEv
> probe-definition(0): _X_ZNKSt13basic_fstreamIcSt11char_traitsIcEE7is_openEv 
> symbol:_X_ZNKSt13basic_fstreamIcSt11char_traitsIcEE7is_openEv file:(null) line:0 offset:0 return:0 lazy:(null)
> 0 arguments
> symbol:catch file:(null) line:0 offset:0 return:0 lazy:(null)
> symbol:throw file:(null) line:0 offset:0 return:0 lazy:(null)
> symbol:rethrow file:(null) line:0 offset:0 return:0 lazy:(null)
> Open Debuginfo file: /usr/lib/debug/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.22
> Try to find probe point from debuginfo.
> Symbol _X_ZNKSt13basic_fstreamIcSt11char_traitsIcEE7is_openEv address found : 8c620
> Matched function: is_open
> found inline addr: 0x8cad0
> Probe point found: is_open+0
> found inline addr: 0x8cac0
> Probe point found: is_open+0
> found inline addr: 0x8cab0
> Probe point found: is_open+0
> Matched function: is_open
> An error occurred in debuginfo analysis (-2).
> Trying to use symbols.
> Opening /sys/kernel/tracing//uprobe_events write=1
> Writing event: p:probe_libstdc++/_X_ZNKSt13basic_fstreamIcSt11char_traitsIcEE7is_openEv /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.22:0x8c620
> Failed to write event: Invalid argument
>   Error: Failed to add events. Reason: Invalid argument (Code: -22)
> 
> [16568.176464] Failed to allocate trace_uprobe.(-22)
> [16568.176468] Failed to parse address or file.
> 
> Aside of that mangled symbols with a @plt suffix do not work at all.

Oh, OK. I could reproduce it. I'll investigate it. :)

Thank you,


-- 
Masami Hiramatsu <mhiramat@kernel.org>