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Re: [PATCH] Fix dwarf2 unwinding through futex functions v2
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Andi Kleen <andi at firstfloor dot org>, libc-alpha at sourceware dot org
- Date: Thu, 06 Mar 2014 11:28:44 -0500
- Subject: Re: [PATCH] Fix dwarf2 unwinding through futex functions v2
- Authentication-results: sourceware.org; auth=none
- References: <1383870168-31055-1-git-send-email-andi at firstfloor dot org> <877g895w10 dot fsf at tassilo dot jf dot intel dot com>
On 03/04/2014 07:28 PM, Andi Kleen wrote:
> Andi Kleen <andi@firstfloor.org> writes:
>
>> From: Andi Kleen <ak@linux.intel.com>
>>
>> When profiling programs with lock problems with perf record -g dwarf, libunwind
>> can currently not backtrace through the futex and unlock functions in pthread.
>> This is because they use out of line sections, and those are not correctly
>> described in dwarf2 (I believe needs dwarf3 or 4).
>
> What happened to this patch? I had assumed it was committed, but it's
> not in current master and the profiling problem is still there.
My last comment was November 11th 2013:
https://sourceware.org/ml/libc-alpha/2013-11/msg00194.html
~~~
I'm OK with this patch as long as you've tried to at least debug a
program built with these new libpthread code and you can unwind through
them. That is to say build some application with the newly built glibc
e.g. -Wl,--dynamic-linker=xxx -Wl,-rpath=xxx:xxx, and you can break on
some instruction deep in the lock sequence and backtrace correctly.
~~~
If you did this verification then I'm happy with you checking it in.
Andreas said he had no opinion.
Cheers,
Carlos.