.
Thread 4 (Thread 2443):
#0  0x00007f04882c5b9b in start_thread () from /lib/libpthread.so.0
No symbol table info available.
#1  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 3 (Thread 2455):
#0  0x00007f04882cabc9 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /lib/libpthread.so.0
No symbol table info available.
#1  0x00007f04867c4602 in ?? () from /usr/lib/libgthread-2.0.so.0
No symbol table info available.
#2  0x00007f04864fd851 in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#3  0x00007f04864fd997 in g_async_queue_timed_pop ()
   from /lib/libglib-2.0.so.0
No symbol table info available.
#4  0x00007f048654d9c8 in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#5  0x00007f048654bb84 in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#6  0x00007f04882c59ca in start_thread () from /lib/libpthread.so.0
No symbol table info available.
#7  0x00007f04860406cd in clone () from /lib/libc.so.6
No symbol table info available.
#8  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 2 (Thread 2444):
#0  0x00007f0486033f53 in poll () from /lib/libc.so.6
No symbol table info available.
#1  0x00007f04684644da in ?? () from /usr/lib/libavahi-common.so.3
No symbol table info available.
#2  0x00007f046846302e in avahi_simple_poll_run ()
   from /usr/lib/libavahi-common.so.3
No symbol table info available.
#3  0x00007f04684637ad in avahi_simple_poll_iterate ()
   from /usr/lib/libavahi-common.so.3
No symbol table info available.
#4  0x00007f04684637dd in avahi_simple_poll_loop ()
   from /usr/lib/libavahi-common.so.3
No symbol table info available.
#5  0x00007f046846432c in ?? () from /usr/lib/libavahi-common.so.3
No symbol table info available.
#6  0x00007f04882c59ca in start_thread () from /lib/libpthread.so.0
No symbol table info available.
#7  0x00007f04860406cd in clone () from /lib/libc.so.6
No symbol table info available.
#8  0x0000000000000000 in ?? ()
No symbol table info available.
.
Thread 1 (Thread 2442):
#0  0x00007f046ef18212 in sanei_usb_open ()
   from /usr/lib/sane/libsane-plustek.so.1
No symbol table info available.
#1  0x00007f046ef21fd7 in sane_plustek_exit ()
   from /usr/lib/sane/libsane-plustek.so.1
No symbol table info available.
#2  0x00007f04862e05ca in sane_dll_exit () from /usr/lib/libsane.so.1
No symbol table info available.
#3  0x0000000000411541 in scanner_free ()
No symbol table info available.
#4  0x0000000000410da0 in ?? ()
No symbol table info available.
#5  0x00007f04869d45de in g_closure_invoke ()
   from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#6  0x00007f04869e8598 in ?? () from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#7  0x00007f04869e9a76 in g_signal_emit_valist ()
   from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#8  0x00007f04869ea033 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#9  0x0000000000414acb in ?? ()
No symbol table info available.
#10 0x0000000000414b0c in window_delete_event_cb ()
No symbol table info available.
#11 0x00007f04879d30e8 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
No symbol table info available.
#12 0x00007f04869d45de in g_closure_invoke ()
   from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#13 0x00007f04869e8598 in ?? () from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#14 0x00007f04869e98b9 in g_signal_emit_valist ()
   from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#15 0x00007f04869ea033 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
No symbol table info available.
#16 0x00007f0487aea02f in ?? () from /usr/lib/libgtk-x11-2.0.so.0
No symbol table info available.
#17 0x00007f04879cc853 in gtk_main_do_event ()
   from /usr/lib/libgtk-x11-2.0.so.0
No symbol table info available.
#18 0x00007f048764086c in ?? () from /usr/lib/libgdk-x11-2.0.so.0
No symbol table info available.
#19 0x00007f04865228c2 in g_main_context_dispatch ()
   from /lib/libglib-2.0.so.0
No symbol table info available.
#20 0x00007f0486526748 in ?? () from /lib/libglib-2.0.so.0
No symbol table info available.
#21 0x00007f0486526c55 in g_main_loop_run () from /lib/libglib-2.0.so.0
No symbol table info available.
#22 0x00007f04879ccb27 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
No symbol table info available.
#23 0x0000000000410744 in main ()
No symbol table info available.