Starting program: /usr/sbin/gpartedbin
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff6a6993a in Glib::wrap_register(unsigned long, Glib::ObjectBase* (*)(_GObject*)) () from /usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1
(gdb) bt
#0 0x00007ffff6a6993a in Glib::wrap_register(unsigned long, Glib::ObjectBase* (*)(_GObject*)) () from /usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1
#1 0x00007ffff6a5969e in Glib::wrap_init() () from /usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1
#2 0x0000000000418ebf in ?? ()
#3 0x00007ffff49aea40 in __libc_start_main (main=0x418e90, argc=1, argv=0x7fffffffe338, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe328) at libc-start.c:289
#4 0x0000000000419575 in ?? ()
You ran an strace of pkexec rather than gparted, and it doesn't show any output indicating that anything went wrong. If you want to strace gparted you need to run it on gpartedbin. A good thing to start with is simply running gparted normally though and showing the output. If it is segfaulting, the best thing to do is to run it under gdb instead of strace and obtain a backtrace ( with the bt command ) when it segfaults.