Re: Wrong Perf Backtraces

From: ahmadkhorrami <ahmadkhorrami@ut.ac.ir>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Linux-trace Users <linux-trace-users@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-trace-users-owner@vger.kernel.org,
	Jin Yao <yao.jin@linux.intel.com>,
	Milian Wolff <milian.wolff@kdab.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Changbin Du <changbin.du@intel.com>,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: Wrong Perf Backtraces
Date: Fri, 27 Mar 2020 15:34:20 +0430	[thread overview]
Message-ID: <decdc878b1bf207c68f1bc9e21178486@ut.ac.ir> (raw)
In-Reply-To: <821540886fc57d7749edee585a50602f@ut.ac.ir>

I do the following:
If this line is in the perf script backtrace:
             7f21ffe256db g_main_context_iteration+0x2b 
(/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.4)
I run the following command:
gdb -batch -ex 'file /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.4' 
-ex 'disass g_main_context_iteration'.

Regards.

On 2020-03-27 15:29, ahmadkhorrami wrote:

> Hi,
> Thanks! Could you tell me what should be changed in order to make the 
> code runnable on your system, if it is possible?
> Regards.
> 
> On 2020-03-27 13:50, Jiri Olsa wrote:
> 
> On Thu, Mar 26, 2020 at 10:49:12PM +0430, ahmadkhorrami wrote:
> 
> Hi,
> Here is the link for the python script:
> https://gofile.io/?c=1ZSLwe
> It is written in python-3 and takes the perf script output as input.
> It looks for consecutive repeated backtrace lines and checks if the 
> function
> in these lines calls itself at the offset in the line (i.e., checks if
> recursion is possible). If not possible it reports an error. Could you 
> check
> to see if any error is detected in your outputs, please?
> I'm getting tons of following output:
> 
> /usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2200.30: No such file or 
> directory.
> No symbol table is loaded.  Use the "file" command.
> 7ffff71b9bc1 gtk_css_node_invalidate_timestamp+0x31 
> (/usr/lib/x86_64-linux-gnu/libgtk-3.so.0.2200.30)
> 
> I assume it's because I have all the dso binaries stored
> under .biuldid path, while you check the output name
> 
> jirka
> 
> Regards.
> On 2020-03-26 20:09, Jiri Olsa wrote:
> 
> On Thu, Mar 26, 2020 at 05:50:27PM +0430, ahmadkhorrami wrote:
> 
> Hi,
> First of all, many thanks for your time. Did you say that the first
> file has
> problems?
> 
> The first file (http://gofile.io/?c=qk6oXv) has repeated gmallocn()s
> while
> the second (https://gofile.io/?c=oGxgSM) also has problems with
> unmatched
> (not necessarily repeated) function calls. I am not sure if the
> kernel for
> the second one is 5.4.7 or the generic Ubuntu kernel. But the first
> one is
> certainly 5.4.7. Just to be clear, there were many instances of these
> unmatched <caller, callees>.
> I can se all the files, but I just can't see the issue yet
> but it's probably because of issues with perf archive..
> 
> let's see if somebody else can chime in
> 
> I have a simple python script that checks for this situation. It
> disassembles functions using GDB and checks the (directly called)
> target of
> each caller. I will put some comments in the script and upload it.
> Could you
> check to see if the python script detects any mismatches in your
> backtraces?
> It takes the perf script output file as input. I will upload the
> script in
> an hour.
> ok
> 
> jirka