c++ - SIGSEGV in QAbstractSocket::writeData when writing 5k of data -

working on arm system , i'm getting sigsegv in qabstractsocket::writedata(char const*, long long). i'm calling via qiodevice::write(char const*, long long) , it's moderately small amount of data. 5k.

i'm checking memory being sent correctly allocated new[] , qiodevice open before sending. smaller packets work reliably exact threshold of when packets large appears vary. i'd binary searched down find under 4k when running code in gdb rose bit didn't binary search find exactly.

there plenty of ram spare, can increase packet size on 1m , new[] still happy.

the qt version 4.8.6.

i'd rather not reveal entire trace project, reveals more details of project i'd to. top few frames are:

#0  0xb6b6ed6c in __memcpy_neon () @ ../ports/sysdeps/arm/armv7/multiarch/memcpy_impl.s:596   #1  0xb6f71dce in qabstractsocket::writedata(char const*, long long) () /usr/lib/arm-linux-gnueabihf/libqtnetwork.so.4   #2  0xb6d9b5fe in qiodevice::write(char const*, long long) () /usr/lib/arm-linux-gnueabihf/libqtcore.so.4 

any ideas on going wrong?