/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_vm_bugreport+0x51f) [0x7f88bb77e13f] vm_dump.c:693
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_bug_context+0xcb) [0x7f88bb61154b] error.c:425
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(sigsegv+0x3e) [0x7f88bb6f1dae] signal.c:879
/lib/x86_64-linux-gnu/libc.so.6 [0x7f88bb203d40]
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(st_delete+0x1f) [0x7f88bb6fb9df] st.c:704
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_hash_delete_entry+0x4a) [0x7f88bb64113a] hash.c:1037
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_hash_delete_m+0x2a) [0x7f88bb6411ba] hash.c:1087
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call0_body.constprop.79+0x28f) [0x7f88bb77308f] vm_eval.c:127
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_call0+0x1ba) [0x7f88bb773cea] vm_eval.c:59
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_funcall+0xca) [0x7f88bb77433a] vm_eval.c:616
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so(_ZL14event_callbackP8em_event+0x2b6) [0x7f88af9d2f03]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so [0x7f88af9d311b]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so(_ZN14EventMachine_t10_RunTimersEv+0xb8) [0x7f88af9bfdac]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so(_ZN14EventMachine_t7RunOnceEv+0x24) [0x7f88af9be8d4]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so(_ZN14EventMachine_t3RunEv+0x18) [0x7f88af9be8aa]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so(evma_run_machine+0x1f) [0x7f88af9d11a5]
/home/ubuntu/.rvm/gems/ruby-2.2.4/gems/eventmachine-1.2.0.1/lib/rubyeventmachine.so [0x7f88af9d3229]
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_cfunc+0x11e) [0x7f88bb76603e] vm_insnhelper.c:1380
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_method+0x11e) [0x7f88bb77c57e] vm_insnhelper.c:1689
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec_core+0x2633) [0x7f88bb76e093] insns.def:1070
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec+0x82) [0x7f88bb771752] vm.c:1435
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(invoke_block_from_c+0x2f6) [0x7f88bb774d96] vm.c:813
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_invoke_proc+0xe0) [0x7f88bb775060] vm.c:878
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_vm_invoke_proc+0x1a) [0x7f88bb77511a] vm.c:897
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(proc_call+0x52) [0x7f88bb620652] proc.c:731
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_cfunc+0x11e) [0x7f88bb76603e] vm_insnhelper.c:1380
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_method+0x11e) [0x7f88bb77c57e] vm_insnhelper.c:1689
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec_core+0x2633) [0x7f88bb76e093] insns.def:1070
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec+0x82) [0x7f88bb771752] vm.c:1435
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(invoke_block_from_c+0x2f6) [0x7f88bb774d96] vm.c:813
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_invoke_proc+0xe0) [0x7f88bb775060] vm.c:878
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_vm_invoke_proc+0x1a) [0x7f88bb77511a] vm.c:897
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(proc_call+0x52) [0x7f88bb620652] proc.c:731
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_cfunc+0x11e) [0x7f88bb76603e] vm_insnhelper.c:1380
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_call_method+0x11e) [0x7f88bb77c57e] vm_insnhelper.c:1689
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec_core+0x2633) [0x7f88bb76e093] insns.def:1070
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_exec+0x82) [0x7f88bb771752] vm.c:1435
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(invoke_block_from_c+0x2f6) [0x7f88bb774d96] vm.c:813
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(vm_invoke_proc+0xe0) [0x7f88bb775060] vm.c:878
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(rb_vm_invoke_proc+0x1a) [0x7f88bb77511a] vm.c:897
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(thread_start_func_2+0x975) [0x7f88bb789d95] thread.c:577
/home/ubuntu/.rvm/rubies/ruby-2.2.4/bin/../lib/libruby.so.2.2(thread_start_func_1+0xbb) [0x7f88bb78a1bb] thread_pthread.c:852
/lib/x86_64-linux-gnu/libpthread.so.0(start_thread+0xc2) [0x7f88bafb7182]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7f88bb2c747d]