For info on ControlPort and Thrift, see the wiki page:

https://wiki.gnuradio.org/index.php/ControlPort

This readme is to address the patch file in the repo for Thrift. We
believe that there is a bug in Thrift itself that occasionally causes
a segfault when shutting down the server. If you run into a problem
when shutting down an application running ControlPort, this might be
the cause. If so, we have included a patch with the source code in
this directory that should be applied to Thrift before rebuilding the
Thrift library:

thrift-codebase-shutdown-patch.diff

Note that we are working off Thrift version 0.9.2, so this patch may
not be relevant or even cleanly apply in later versions of Thrift.

We are also still trying to track down another shutdown problem with
Thrift that again appears to be related to their code. If a segfault
persists after the above patch is applied to Thrift, do a backtrace in
GDB to see what the error looks like. If it is different than the
following backtrace, definitely report it to the Discuss GNU Radio
Mailing List as a known bug. If you see the same backtrace as here,
this is a known bug that occurs very irregularly, but help in tracing
down the cause is appreciated.

#0  0x00007f07b5b478c2 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007f07b5b478c2 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f07b5b4856d in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007f07afc924c5 in std::locale::_Impl::~_Impl() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00007f07afc925fd in std::locale::~locale() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4  0x00007f07b5b05259 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#5  0x00007f07b5b052a5 in exit () from /lib/x86_64-linux-gnu/libc.so.6
#6  0x000000000042fb83 in Py_Exit ()
#7  0x000000000042fcb9 in ?? ()
#8  0x000000000042ec32 in PyErr_PrintEx ()
#9  0x0000000000469f2f in PyRun_SimpleFileExFlags ()
#10 0x000000000046ab81 in Py_Main ()
#11 0x00007f07b5aeaec5 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
#12 0x000000000057497e in _start ()
