I am porting a C++ app on windows 7 x64, using mingw32 (i'm build a 32 bits app)

I used the binary mingw-get-inst-20120426.exe, cause i wanted to use the gcc 4.6.x for some library compatibility.

Just for information, the gdb provided with this package is gdb 7.4 

Eveything works fine, from compilation to execution.

But when I trying to debug with gdb, i get a sigsev :
#0  0x6fc899fc in libstdc++-6!_ZNSsC1ERKSs () from D:\DEV\INSTALL\MinGW\bin\libstdc++-6.dll

The previous gdb line refers to a line of one of my header, a constructor with some initialization
StringUtils(const std::string& src) : _tmp(const_cast<std::string&>(src)) , _str(_tmp) {} ;

I have no problem on exec & debug on linux, nor on exec on win7 ... It's just the debug of win7 that fails here, I don't know why. 
I know it doesn't necessarily mean that the problem doesn't come from my code, but I don't see where, so i'm wondering if there is a known problem with gdb on mingw32 ?

Thanks for help :)