From: "thommyj at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: elfutils-devel@sourceware.org
Subject: [Bug libdw/21174] libdw with perf: duplication of entries in callstack
Date: Fri, 17 Feb 2017 09:47:00 -0000 [thread overview]
Message-ID: <bug-21174-10460-q3df9RRz9T@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-21174-10460@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=21174
--- Comment #3 from Thommy Jakobsson <thommyj at gmail dot com> ---
(In reply to Mark Wielaard from comment #1)
> There is no good way to tell. It could happen if the function calls itself
> (although you would expect the pc to be different).
I did check the assembler code for one case, and couldn't find anything
special, no calling of itself (although I didn't really know what to search for
either so I might have missed something =) ). Checking the code for the
specific example I pasted here it seems to be a return address for another
call. See attached file.
> How does perf call the libdw getframe function?
The actual call looks like this
err = dwfl_getthread_frames(ui.dwfl, thread->tid, frame_callback, &ui);
but I assume that you want some specific information? The entire wrapper around
libdw can be found here
http://lxr.free-electrons.com/source/tools/perf/util/unwind-libdw.c?v=4.4
> What does the CFI look like at that address?
How can I find this out? dwarfdump?
BR,
Thommy Jakobsson
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next prev parent reply other threads:[~2017-02-17 9:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-17 6:49 [Bug libdw/21174] New: " thommyj at gmail dot com
2017-02-17 9:11 ` [Bug libdw/21174] " mark at klomp dot org
2017-02-17 9:39 ` thommyj at gmail dot com
2017-02-17 9:47 ` thommyj at gmail dot com [this message]
2017-02-17 10:07 ` mark at klomp dot org
2017-02-17 10:16 ` mark at klomp dot org
2017-02-17 14:42 ` thommyj at gmail dot com
2017-02-17 14:43 ` thommyj at gmail dot com
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