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List:       kde-core-devel
Subject:    Re: Crashes on closing applications
From:       Rolf Eike Beer <kde () opensource ! sf-tec ! de>
Date:       2010-07-11 14:25:39
Message-ID: 201007111625.40288.kde () opensource ! sf-tec ! de
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Thomas Lübking wrote:
> Am Sunday 11 July 2010 schrieb Rolf Eike Beer:
> > I just wonder why this is libstdc++-v3, openSuSE 11.2 uses gcc 4.4 by
> > default?
> 
> I don't think the libstdc++ version ever changed since gcc3 (and indeed,
> it's -v3 on gcc 4.5 as well)
> 
> The whole thing looks quite like a memory ("0x6" ...) corruption, but
> testing
> 
> gcc -O[n] std_string_seg.cpp -lstdc++ -o std_string_seg | n = 0-3
> 
> on the -plain std::string, no KDE- attachment doesn't fail at all
> (i however don't know how -optimized- my libstdc++ was compiled)
> 
> So this is either in the particular OpenSuSE libstdc++ or an overflow in
> some KDE lib.
> 
> I also attached a binary, compiled and linked on arch, 32bit x86, gcc4.5
> prerelease, -O2, lisbstdc++.so.6.0.14 - maybe test it with gdb

It's not that trivial, otherwise I think it would have been long solved. For 
example if you start dolphin and immediately close it afterwards the crash 
does not happen. If you do some work before closing it it will crash.

I also suspect not the string object itself be the problem, but the memory 
within that (i.e. the string data). We see those crashes with all string 
objects being on the stack as I suspect the report from that google search 
does too.

And once again: "delete 0" is fine but must return immediately. In the 
backtrace it doesn't but tries to dereference something. Although I find that 
offset 0x6 suspicious, I would have expected a multiple of 4 for any offsets 
holding a pointer.

Eike

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