Bug 1277840

Summary: after emacs crash, XIfEvent stuck in busy loop
Product: [Fedora] Fedora Reporter: Stephan Bergmann <sbergman>
Component: libX11Assignee: Adam Jackson <ajax>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 23CC: ajax, sandmann
Target Milestone: ---   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-12-20 15:21:05 UTC Type: Bug
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Stephan Bergmann 2015-11-04 08:36:32 UTC 
A /usr/bin/emacs process happened to crash for me, and then got stuck with 100% CPU load.  Looking with GDB, what happened is that the main thread is stuck in a busy loop in XIfEvent repeatedly calling _XReadEvents, which keeps returning early with

> if(dpy->flags & XlibDisplayIOError)
>   return;

(where dpy->flags == XlibDisplayIOError, aka 1).  It looks like maybe XIfEvent should also break out of its loop under that error condition?

Package versions:
libX11-1.6.3-2.fc23.x86_64
emacs-24.5-6.fc23.x86_64

Full stack:

> #0  0x00007fa5c8b8bd40 in _XReadEvents (dpy=dpy@entry=0x13d8c00) at /usr/src/debug/libX11-1.6.3/src/xcb_io.c:379
> #1  0x00007fa5c8b737f9 in XIfEvent (dpy=0x13d8c00, event=event@entry=0x7ffc29ce5de0, predicate=predicate@entry=0x7fa5c8bbb830 <_CheckCMEvent>, arg=arg@entry=0x2b70000 "@a\350ȥ\177") at /usr/src/debug/libX11-1.6.3/src/IfEvent.c:68
> #2  0x00007fa5c8bbbfc3 in _XimXRead (im=0x2b70000, recv_buf=0x7ffc29ce67d0 "", buf_len=2048, ret_len=0x7ffc29ce5f14) at /usr/src/debug/libX11-1.6.3/modules/im/ximcp/imTrX.c:476
> #3  0x00007fa5c8bbcbf7 in _XimReadData (im=im@entry=0x2b70000, len=len@entry=0x7ffc29ce5f76, buf=buf@entry=0x7ffc29ce67d0 "", buf_size=buf_size@entry=2048) at /usr/src/debug/libX11-1.6.3/modules/im/ximcp/imTransR.c:165
> #4  0x00007fa5c8bbced1 in _XimRead (im=im@entry=0x2b70000, len=len@entry=0x7ffc29ce5fce, buf=buf@entry=0x7ffc29ce67d0 "", buf_size=buf_size@entry=2048, predicate=predicate@entry=0x7fa5c8baa9a0 <_XimDestroyICCheck>, arg=arg@entry=0x13e7260 "\340`\350ȥ\177") at /usr/src/debug/libX11-1.6.3/modules/im/ximcp/imTransR.c:235
> #5  0x00007fa5c8baaeb0 in _XimProtoDestroyIC (xic=0x13e7260) at /usr/src/debug/libX11-1.6.3/modules/im/ximcp/imDefIc.c:914
> #6  0x00007fa5c8b98df2 in XDestroyIC (ic=0x13e7260) at /usr/src/debug/libX11-1.6.3/src/xlibi18n/ICWrap.c:265
> #7  0x00000000004cffaf in free_frame_xic (f=f@entry=0x1175248) at /usr/src/debug/emacs-24.5/src/xfns.c:2087
> #8  0x00000000004c8a7c in x_free_frame_resources (f=<optimized out>) at /usr/src/debug/emacs-24.5/src/xterm.c:9275
> #9  0x00000000004c8f6b in x_destroy_window (f=<optimized out>) at /usr/src/debug/emacs-24.5/src/xterm.c:9383
> #10 0x000000000042614d in delete_frame (frame=<optimized out>, force=<optimized out>) at /usr/src/debug/emacs-24.5/src/frame.c:1387
> #11 0x00000000004bf3f0 in x_connection_closed (dpy=<optimized out>, error_message=<optimized out>) at /usr/src/debug/emacs-24.5/src/xterm.c:7635
> #12 0x00000000004bf4ef in x_io_error_quitter (display=<optimized out>) at /usr/src/debug/emacs-24.5/src/xterm.c:7762
> #13 0x00007fa5c8b8e43e in _XIOError (dpy=dpy@entry=0x13d8c00) at /usr/src/debug/libX11-1.6.3/src/XlibInt.c:1464
> #14 0x00007fa5c8b8c49a in _XReply (dpy=dpy@entry=0x13d8c00, rep=rep@entry=0x7ffc29ce72e0, extra=extra@entry=0, discard=discard@entry=1) at /usr/src/debug/libX11-1.6.3/src/xcb_io.c:708
> #15 0x00007fa5c8b87bdd in XSync (dpy=0x13d8c00, discard=0) at /usr/src/debug/libX11-1.6.3/src/Sync.c:44
> #16 0x00007fa5ca9d4981 in gdk_window_process_all_updates () at /usr/src/debug/gtk+-3.18.2/gdk/gdkwindow.c:3785
> #17 0x00007fa5ca9d4981 in gdk_window_process_all_updates () at /usr/src/debug/gtk+-3.18.2/gdk/gdkwindow.c:3851
> #18 0x00000000004c411b in x_catch_errors (dpy=<optimized out>) at /usr/src/debug/emacs-24.5/src/xterm.c:7490
> #19 0x00000000004d44c6 in x_get_foreign_selection (selection_symbol=<optimized out>, target_type=12640194, time_stamp=12331890, frame=frame@entry=18305613) at /usr/src/debug/emacs-24.5/src/xselect.c:1210
> #20 0x00000000004d468c in x_clipboard_manager_save (frame=frame@entry=18305613) at /usr/src/debug/emacs-24.5/src/xselect.c:2171
> #21 0x000000000055feab in internal_condition_case_1 (bfun=bfun@entry=0x4d4610 <x_clipboard_manager_save>, arg=arg@entry=18305613, handlers=<optimized out>, hfun=hfun@entry=0x4d2fd0 <x_clipboard_manager_error_2>) at /usr/src/debug/emacs-24.5/src/eval.c:1372
> #22 0x00000000004d5c8e in x_clipboard_manager_save_all () at /usr/src/debug/emacs-24.5/src/xselect.c:2256
> #23 0x00000000004ec16c in Fkill_emacs (arg=arg@entry=60) at /usr/src/debug/emacs-24.5/src/emacs.c:1945
> #24 0x00000000004ec27c in terminate_due_to_signal (sig=15, backtrace_limit=backtrace_limit@entry=40) at /usr/src/debug/emacs-24.5/src/emacs.c:358
> #25 0x000000000050519e in handle_fatal_signal (sig=<optimized out>) at /usr/src/debug/emacs-24.5/src/sysdep.c:1630
> #26 0x000000000050601d in deliver_process_signal (sig=15, handler=0x505190 <handle_fatal_signal>) at /usr/src/debug/emacs-24.5/src/sysdep.c:1570
> #27 0x00007fa5c554d9f0 in <signal handler called> () at /lib64/libpthread.so.0
> #28 0x00007fa5c554d8c9 in raise (sig=15) at /usr/src/debug/glibc-2.22/sysdeps/unix/sysv/linux/pt-raise.c:36
> #29 0x00007fa5c154ed30 in ffi_call_unix64 () at /usr/src/debug/libffi-3.1/src/x86/unix64.S:76
> #30 0x00007fa5c154e79b in ffi_call (cif=cif@entry=0x7ffc29ce7dc0, fn=<optimized out>, rvalue=0x7ffc29ce7d10, avalue=avalue@entry=0x7ffc29ce7cb0) at /usr/src/debug/libffi-3.1/src/x86/ffi64.c:525
> #31 0x00007fa5c95f74f5 in g_cclosure_marshal_generic_va (closure=0x29ab890, return_value=0x0, instance=0x146c150, args_list=<optimized out>, marshal_data=0x7fa5c9906520 <g_dbus_connection_real_closed>, n_params=2, param_types=0x29ab900) at /usr/src/debug/glib-2.46.1/gobject/gclosure.c:1600
> #32 0x00007fa5c95f69d4 in _g_closure_invoke_va (closure=closure@entry=0x29ab890, return_value=return_value@entry=0x0, instance=instance@entry=0x146c150, args=args@entry=0x7ffc29ce8060, n_params=<optimized out>, param_types=0x29ab900) at /usr/src/debug/glib-2.46.1/gobject/gclosure.c:864
> #33 0x00007fa5c96112bd in g_signal_emit_valist (instance=0x146c150, signal_id=<optimized out>, detail=0, var_args=var_args@entry=0x7ffc29ce8060) at /usr/src/debug/glib-2.46.1/gobject/gsignal.c:3292
> #34 0x00007fa5c96118ff in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=detail@entry=0) at /usr/src/debug/glib-2.46.1/gobject/gsignal.c:3439
> #35 0x00007fa5c9905105 in emit_closed_in_idle (user_data=0x7fa5a800a030) at /usr/src/debug/glib-2.46.1/gio/gdbusconnection.c:1357
> #36 0x00007fa5c92f7e3a in g_main_context_dispatch (context=0x13d65f0) at /usr/src/debug/glib-2.46.1/glib/gmain.c:3154
> #37 0x00007fa5c92f7e3a in g_main_context_dispatch (context=context@entry=0x13d65f0) at /usr/src/debug/glib-2.46.1/glib/gmain.c:3769
> #38 0x00000000005dc0d0 in xg_select (fds_lim=14, rfds=rfds@entry=0x7ffc29ce88b0, wfds=wfds@entry=0x7ffc29ce8930, efds=efds@entry=0x0, timeout=timeout@entry=0x7ffc29ce8890, sigmask=sigmask@entry=0x0) at /usr/src/debug/emacs-24.5/src/xgselect.c:159
> #39 0x00000000005a26a9 in wait_reading_process_output (time_limit=time_limit@entry=45, nsecs=nsecs@entry=0, read_kbd=read_kbd@entry=-1, do_display=do_display@entry=true, wait_for_cell=12331890, wait_proc=wait_proc@entry=0x0, just_wait_proc=0) at /usr/src/debug/emacs-24.5/src/process.c:4606
> #40 0x0000000000422663 in sit_for (timeout=<optimized out>, reading=reading@entry=true, display_option=display_option@entry=1) at /usr/src/debug/emacs-24.5/src/dispnew.c:5867
> #41 0x00000000004f783c in read_char (commandflag=1, map=map@entry=51788854, prev_event=12331890, used_mouse_menu=used_mouse_menu@entry=0x7ffc29ce8edb, end_time=end_time@entry=0x0) at /usr/src/debug/emacs-24.5/src/keyboard.c:2810
> #42 0x00000000004f8a88 in read_key_sequence (keybuf=keybuf@entry=0x7ffc29ce8fe0, prompt=12331890, dont_downcase_last=dont_downcase_last@entry=false, can_return_switch_frame=can_return_switch_frame@entry=true, fix_current_buffer=fix_current_buffer@entry=true, prevent_redisplay=prevent_redisplay@entry=false, bufsize=30) at /usr/src/debug/emacs-24.5/src/keyboard.c:9089
> #43 0x00000000004fa88e in command_loop_1 () at /usr/src/debug/emacs-24.5/src/keyboard.c:1453
> #44 0x000000000055fd87 in internal_condition_case (bfun=bfun@entry=0x4fa670 <command_loop_1>, handlers=<optimized out>, hfun=hfun@entry=0x4f11c0 <cmd_error>) at /usr/src/debug/emacs-24.5/src/eval.c:1348
> #45 0x00000000004ec642 in command_loop_2 (ignore=ignore@entry=12331890) at /usr/src/debug/emacs-24.5/src/keyboard.c:1178
> #46 0x000000000055fc6b in internal_catch (tag=12379170, func=func@entry=0x4ec620 <command_loop_2>, arg=12331890) at /usr/src/debug/emacs-24.5/src/eval.c:1112
> #47 0x00000000004f0d83 in recursive_edit_1 () at /usr/src/debug/emacs-24.5/src/keyboard.c:1157
> #48 0x00000000004f0d83 in recursive_edit_1 () at /usr/src/debug/emacs-24.5/src/keyboard.c:778
> #49 0x00000000004f10d8 in Frecursive_edit () at /usr/src/debug/emacs-24.5/src/keyboard.c:849
> #50 0x0000000000418587 in main (argc=<optimized out>, argv=0x7ffc29ce9348) at /usr/src/debug/emacs-24.5/src/emacs.c:1642
Comment 1 Fedora End Of Life 2016-11-24 13:03:40 UTC 
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Comment 2 Fedora End Of Life 2016-12-20 15:21:05 UTC 
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
no longer maintained, which means that it will not receive any further
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