.
Thread 3 (Thread 0x7fce10528700 (LWP 2874)):
#0  0x00007fce159c8951 in __GI___poll (fds=0x55b37260fd10, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
        resultvar = 18446744073709551100
        sc_cancel_oldtype = 0
        sc_ret = <optimized out>
#1  0x00007fce15f0a169 in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x55b37260fd10, timeout=<optimized out>, context=0x55b372638760) at ../../../../glib/gmain.c:4187
        ret = <optimized out>
        errsv = <optimized out>
        poll_func = 0x7fce15f19640 <g_poll>
        poll_func = <optimized out>
        ret = <optimized out>
        errsv = <optimized out>
#2  g_main_context_iterate (context=context@entry=0x55b372638760, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../../glib/gmain.c:3881
        max_priority = 2147483647
        timeout = -1
        some_ready = <optimized out>
        nfds = 1
        allocated_nfds = 1
        fds = 0x55b37260fd10
#3  0x00007fce15f0a27c in g_main_context_iteration (context=0x55b372638760, may_block=may_block@entry=1) at ../../../../glib/gmain.c:3947
        retval = <optimized out>
#4  0x00007fce15f0a2c1 in glib_worker_main (data=<optimized out>) at ../../../../glib/gmain.c:5742
No locals.
#5  0x00007fce15f31645 in g_thread_proxy (data=0x55b372638c00) at ../../../../glib/gthread.c:784
        thread = 0x55b372638c00
        _g_boolean_var_ = <optimized out>
#6  0x00007fce15ca77fc in start_thread (arg=0x7fce10528700) at pthread_create.c:465
        pd = 0x7fce10528700
        now = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140523013834496, -7854264217586426320, 140728799671006, 140728799671007, 140523013834496, 140523013835200, 7826179636803608112, 7826174070343540272}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <optimized out>
        pagesize_m1 = <optimized out>
        sp = <optimized out>
        freesize = <optimized out>
        __PRETTY_FUNCTION__ = "start_thread"
        frame = <optimized out>
#7  0x00007fce159d4b5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
No locals.
.
Thread 2 (Thread 0x7fce0fd27700 (LWP 2877)):
#0  0x00007fce159c8951 in __GI___poll (fds=0x55b37261a1e0, nfds=3, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
        resultvar = 18446744073709551100
        sc_cancel_oldtype = 0
        sc_ret = <optimized out>
#1  0x00007fce15f0a169 in g_main_context_poll (priority=<optimized out>, n_fds=3, fds=0x55b37261a1e0, timeout=<optimized out>, context=0x55b372646380) at ../../../../glib/gmain.c:4187
        ret = <optimized out>
        errsv = <optimized out>
        poll_func = 0x7fce15f19640 <g_poll>
        poll_func = <optimized out>
        ret = <optimized out>
        errsv = <optimized out>
#2  g_main_context_iterate (context=0x55b372646380, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../../glib/gmain.c:3881
        max_priority = 2147483647
        timeout = -1
        some_ready = <optimized out>
        nfds = 3
        allocated_nfds = 3
        fds = 0x55b37261a1e0
#3  0x00007fce15f0a502 in g_main_loop_run (loop=0x55b37261a040) at ../../../../glib/gmain.c:4082
        self = <optimized out>
        __func__ = "g_main_loop_run"
#4  0x00007fce164f3b26 in gdbus_shared_thread_func (user_data=0x55b372641ae0) at ../../../../gio/gdbusprivate.c:275
        data = 0x55b372641ae0
#5  0x00007fce15f31645 in g_thread_proxy (data=0x55b372638ca0) at ../../../../glib/gthread.c:784
        thread = 0x55b372638ca0
        _g_boolean_var_ = <optimized out>
#6  0x00007fce15ca77fc in start_thread (arg=0x7fce0fd27700) at pthread_create.c:465
        pd = 0x7fce0fd27700
        now = <optimized out>
        unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140523005441792, -7854264217586426320, 140728799671390, 140728799671391, 140523005441792, 140523005442496, 7826152148476042800, 7826174070343540272}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
        not_first_call = <optimized out>
        pagesize_m1 = <optimized out>
        sp = <optimized out>
        freesize = <optimized out>
        __PRETTY_FUNCTION__ = "start_thread"
        frame = <optimized out>
#7  0x00007fce159d4b5f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
No locals.
.
Thread 1 (Thread 0x7fce1702c580 (LWP 2869)):
#0  0x00007fce16a1f4bf in ?? () from /tmp/apport_sandbox_qxC8y5/usr/lib/x86_64-linux-gnu/libcups.so.2
No symbol table info available.
#1  0x000055b3707d9803 in process_new_notifications (user_data=0x55b372629070) at gsd-print-notifications-manager.c:916
        manager = 0x55b372629070
        attr = <optimized out>
        notify_subscribed_event = 0x0
        printer_name = 0x0
        notify_text = 0x0
        notify_printer_uri = 0x0
        job_state_reasons = 0x0
        job_name = 0x0
        attr_name = <optimized out>
        printer_is_accepting_jobs = 0
        printer_state_reasons = 0x0
        reasons = <optimized out>
        notify_job_id = 0
        request = 0x55b37263e190
        response = <optimized out>
        printer_state = -1
        job_state = -1
        job_impressions_completed = -1
        notify_sequence_number = -1
        i = <optimized out>
#2  0x00007fce164df864 in emit_signal_instance_in_idle_cb (data=0x7fce0001b4e0) at ../../../../gio/gdbusconnection.c:3720
        signal_instance = 0x7fce0001b4e0
        parameters = 0x7fce0000f520
        has_subscription = 1
#3  0x00007fce15f09e25 in g_main_dispatch (context=0x55b3726279d0) at ../../../../glib/gmain.c:3148
        dispatch = 0x7fce15f06760 <g_idle_dispatch>
        prev_source = 0x0
        was_in_call = 0
        user_data = 0x7fce0001b4e0
        callback = 0x7fce164df7f0 <emit_signal_instance_in_idle_cb>
        cb_funcs = 0x7fce161d1280 <g_source_callback_funcs>
        cb_data = 0x7fce00008840
        need_destroy = <optimized out>
        source = 0x7fce00014d90
        current = 0x55b3726406a0
        i = 0
        current = <optimized out>
        i = <optimized out>
        source = <optimized out>
        _g_boolean_var_ = <optimized out>
        was_in_call = <optimized out>
        user_data = <optimized out>
        callback = <optimized out>
        cb_funcs = <optimized out>
        cb_data = <optimized out>
        need_destroy = <optimized out>
        dispatch = <optimized out>
        prev_source = <optimized out>
        _g_boolean_var_ = <optimized out>
#4  g_main_context_dispatch (context=context@entry=0x55b3726279d0) at ../../../../glib/gmain.c:3813
No locals.
#5  0x00007fce15f0a1f0 in g_main_context_iterate (context=0x55b3726279d0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../../glib/gmain.c:3886
        max_priority = 2147483647
        timeout = 3499914
        some_ready = 1
        nfds = <optimized out>
        allocated_nfds = 1
        fds = 0x55b37261d6e0
#6  0x00007fce15f0a502 in g_main_loop_run (loop=0x55b37260aa70) at ../../../../glib/gmain.c:4082
        self = <optimized out>
        __func__ = "g_main_loop_run"
#7  0x000055b3707d7905 in main (argc=<optimized out>, argv=<optimized out>) at ../../plugins/common/daemon-skeleton.h:209
        error = 0x0
        context = <optimized out>
        loop = 0x55b37260aa70