debugger hanging upon entering some functions

After stepping into certain functions debugger hangs showing progress wheel on the locals and expressions view. Qt Creator 3.4.1. GDB 7.9. Python 2.7.10( Anaconda 2.2.0 (64-bit)). top is showing that gdb uses 100% of processor time. I did strace on the gdb process: there is one system call executed over and over.

The debugger log view output for the final period and representative strace of gdb log are attached.