(gdb) where
#0  0x00007f364608454f in ?? () from /lib64/libgcc_s.so.1
#1  0x00007f3646084e1b in _Unwind_Backtrace () from /lib64/libgcc_s.so.1
#2  0x00007f3646aec73e in backtrace () from /lib64/libc.so.6
#3  0x00000000004e5e4b in rb_vm_bugreport () at vm_dump.c:601
#4  0x0000000000513aee in report_bug (file=<value optimized out>, line=<value optimized out>, fmt=0x53bbdf "Segmentation fault", args=0x86f8c0) at error.c:215
#5  0x0000000000513c51 in rb_bug (fmt=0x53bbdf "Segmentation fault") at error.c:230
#6  0x000000000049243f in sigsegv (sig=<value optimized out>, info=<value optimized out>, ctx=<value optimized out>) at signal.c:600
#7  <signal handler called>
#8  0x000000000001a007 in ?? ()
#9  0x00007f3646a3bea2 in ?? () from /lib64/libc.so.6
#10 0x00007f3646a3c84c in qsort_r () from /lib64/libc.so.6
#11 0x00007f36462991c8 in rb_dlcfunc_call (self=<value optimized out>, ary=<value optimized out>) at cfunc.c:276
#12 0x00000000004e1b57 in vm_call_method (th=0x7a9b90, cfp=0x7f36479c9b30, num=1, blockptr=0x1, flag=<value optimized out>, id=5536, mn=0xa10ea0, recv=11220680) at vm_insnhelper.c:374
#13 0x00000000004d6d74 in vm_exec_core (th=0x7a9b90, initial=<value optimized out>) at insns.def:999
#14 0x00000000004dbe7c in vm_exec (th=0x7a9b90) at vm.c:1042
#15 0x00000000004e34f2 in rb_yield (val=11225640) at vm.c:488
#16 0x00000000004ef9bc in rb_ary_each (ary=11225400) at array.c:1343
#17 0x00000000004e1b57 in vm_call_method (th=0x7a9b90, cfp=0x7f36479c9d10, num=0, blockptr=0x7f36479c9d39, flag=<value optimized out>, id=424, mn=0x7ef270, recv=11225400) at vm_insnhelper.c:374
#18 0x00000000004d6d74 in vm_exec_core (th=0x7a9b90, initial=<value optimized out>) at insns.def:999
#19 0x00000000004dbe7c in vm_exec (th=0x7a9b90) at vm.c:1042
#20 0x00000000004e34f2 in rb_yield (val=12190560) at vm.c:488
#21 0x00000000004ef9bc in rb_ary_each (ary=11359480) at array.c:1343
#22 0x00000000004e1b57 in vm_call_method (th=0x7a9b90, cfp=0x7f36479c9e30, num=0, blockptr=0x7f36479c9e59, flag=<value optimized out>, id=424, mn=0x7ef270, recv=11359480) at vm_insnhelper.c:374
#23 0x00000000004d6d74 in vm_exec_core (th=0x7a9b90, initial=<value optimized out>) at insns.def:999
#24 0x00000000004dbe7c in vm_exec (th=0x7a9b90) at vm.c:1042
#25 0x00000000004de52d in vm_invoke_proc (th=0x7a9b90, proc=0x9f42f0, self=10000120, argc=0, argv=0xad57b0, blockptr=0x0) at vm.c:488
#26 0x000000000041a5d2 in rb_exec_end_proc () at eval_jump.c:133
#27 0x000000000041a654 in ruby_finalize_0 () at eval.c:107
#28 0x000000000041a837 in ruby_cleanup (ex=0) at eval.c:142
#29 0x000000000041aa4a in ruby_run_node (n=0x7b6538) at eval.c:233
#30 0x0000000000417cdd in main (argc=2, argv=0x7fff4fa3a788) at main.c:35
(gdb)