[Bug 57731] Futex hang when exiting using the window close button

[Matt Zimmerman]

Public bug reported:

I had been using xchat-gnome for some hours, and clicked the window
close button to exit.  xchat-gnome hung, and metacity's force dialog was
displayed.  strace showed that it was hung in a futex syscall:

futex(0xb762e120, FUTEX_WAIT, 2, NULL <unfinished ...>

and gdb showed this backtrace:

#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb75d6d0e in __lll_mutex_lock_wait () from /lib/tls/i686/cmov/libc.so.6
#2  0xb756762e in _L_mutex_lock_4345 () from /lib/tls/i686/cmov/libc.so.6
#3  0xb755ff03 in _IO_default_xsputn () from /lib/tls/i686/cmov/libc.so.6
#4  0xb7f12d28 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#5  0xb7f178d5 in _dl_make_stack_executable () from /lib/ld-linux.so.2
#6  0xb7f13a96 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#7  0xb7f173c9 in _dl_make_stack_executable () from /lib/ld-linux.so.2
#8  0xb75ff7e2 in do_dlopen () from /lib/tls/i686/cmov/libc.so.6
#9  0xb7f13a96 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#10 0xb75ff995 in *__GI___libc_dlopen_mode () from /lib/tls/i686/cmov/libc.so.6
#11 0xb75dd4a9 in init () from /lib/tls/i686/cmov/libc.so.6
#12 0xb7daf9bb in pthread_once () from /lib/tls/i686/cmov/libpthread.so.0
#13 0xb75dd5a8 in *__GI___backtrace () from /lib/tls/i686/cmov/libc.so.6
#14 0xb755bd01 in __libc_message () from /lib/tls/i686/cmov/libc.so.6
#15 0xb756375e in _int_free () from /lib/tls/i686/cmov/libc.so.6
#16 0xb7563a24 in *__GI___libc_free () from /lib/tls/i686/cmov/libc.so.6
#17 0x0809c843 in session_free ()
#18 0x0809c67f in xchat_exit ()
#19 0xb7a09780 in _gtk_marshal_BOOLEAN__BOXED () from /usr/lib/libgtk-x11-2.0.so.0
#20 0xb76f57dc in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#21 0xb77057d4 in g_signal_chain_from_overridden () from /usr/lib/libgobject-2.0.so.0
#22 0xb7706ac2 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#23 0xb7706eae in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#24 0xb7b1cbf8 in gtk_widget_get_default_style () from /usr/lib/libgtk-x11-2.0.so.0
#25 0xb7a03f46 in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#26 0xb788c87a in _gdk_events_init () from /usr/lib/libgdk-x11-2.0.so.0
#27 0xb7682cf6 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#28 0xb7685fce in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#29 0xb7686358 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#30 0xb7a041f4 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#31 0x080628dd in fe_main ()
#32 0x0809d53b in main ()

** Affects: xchat-gnome (Ubuntu)
     Importance: Untriaged
         Status: Unconfirmed

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Futex hang when exiting using the window close button
https://launchpad.net/bugs/57731