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<base href="https://bugs.freedesktop.org/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Some programs (emacs,urxvt) hang at xcb_wait_for_event"
href="https://bugs.freedesktop.org/show_bug.cgi?id=78081">78081</a>
</td>
</tr>
<tr>
<th>Assignee</th>
<td>xcb@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>Some programs (emacs,urxvt) hang at xcb_wait_for_event
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>xcb@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Reporter</th>
<td>n142857@gmail.com
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>1.10
</td>
</tr>
<tr>
<th>Component</th>
<td>Library
</td>
</tr>
<tr>
<th>Product</th>
<td>XCB
</td>
</tr></table>
<p>
<div>
<pre>Hi, in last months (early 2014) I started seeing strange hangs in Emacs and
urxvt which I think are due to XCB. I use GNU/Linux Debian with
libxcb1==1.10-2, wmii==3.10~20120413+hg2813-6 window manager.
The program window becomes black and doesn't react to mouse/keyboard events
or kill signals (I tried many numbers). I have to kill the process (or mess up
gdb until it dies with SIGSEGV). Same for both programs.
*) Emacs hung. Version: GNU Emacs 24.4.50.1 (x86_64-unknown-linux-gnu, X
toolkit, Xaw scroll bars) of 2014-04-19
(gdb) bt
#0 0x00007f3e744de710 in __poll_nocancel () at
../sysdeps/unix/syscall-template.S:81
#1 0x00007f3e73fea232 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2 0x00007f3e73febd0f in xcb_wait_for_event () from
/usr/lib/x86_64-linux-gnu/libxcb.so.1
#3 0x00007f3e75aa3918 in _XReadEvents () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#4 0x00007f3e75a8beb1 in XIfEvent () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#5 0x00007f3e75ad2764 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#6 0x00007f3e75ad33c0 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#7 0x00007f3e75ad36b1 in _XimRead () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#8 0x00007f3e75ac2096 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#9 0x00007f3e75ab02fd in XSetICValues () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#10 0x000000000050f099 in xic_set_preeditarea (w=0x5113858, x=768, y=56) at
xfns.c:2106
#11 0x0000000000504c0a in x_draw_window_cursor (w=0x5113858,
glyph_row=0x18039870, x=768, y=56, cursor_type=FILLED_BOX_CURSOR,
cursor_width=1, on_p=true, active_p=true)
at xterm.c:7312
#12 0x0000000000477484 in display_and_set_cursor (w=0x5113858, on=true,
hpos=96, vpos=4, x=768, y=56) at xdisp.c:27214
#13 0x00000000004f7070 in x_update_window_end (w=0x5113858, cursor_on_p=true,
mouse_face_overwritten_p=false) at xterm.c:582
#14 0x00000000004133ae in update_window (w=0x5113858, force_p=true) at
dispnew.c:3486
#15 0x00000000004129f8 in update_window_tree (w=0x5113858, force_p=true) at
dispnew.c:3161
#16 0x00000000004129bd in update_window_tree (w=0x524ef10, force_p=true) at
dispnew.c:3159
#17 0x00000000004126d1 in update_frame (f=0x5113640, force_p=true,
inhibit_hairy_id_p=false) at dispnew.c:3059
#18 0x000000000044b5ee in redisplay_internal () at xdisp.c:13873
#19 0x00000000004495cd in redisplay () at xdisp.c:13056
#20 0x00000000005292ed in read_char (commandflag=1, map=375333574,
prev_event=12839794, used_mouse_menu=0x7fff8cc0c69f, end_time=0x0) at
keyboard.c:2751
#21 0x0000000000534c1a in read_key_sequence (keybuf=0x7fff8cc0c880, bufsize=30,
prompt=12839794, dont_downcase_last=false, can_return_switch_frame=true,
fix_current_buffer=true, prevent_redisplay=false) at keyboard.c:9076
#22 0x0000000000526840 in command_loop_1 () at keyboard.c:1449
#23 0x00000000005b3a60 in internal_condition_case (bfun=0x526487
<command_loop_1>, handlers=12890850, hfun=0x525d99 <cmd_error>) at eval.c:1354
#24 0x00000000005261e1 in command_loop_2 (ignore=12839794) at keyboard.c:1174
#25 0x00000000005b3272 in internal_catch (tag=12886738, func=0x5261bb
<command_loop_2>, arg=12839794) at eval.c:1118
#26 0x000000000052618f in command_loop () at keyboard.c:1153
#27 0x0000000000525994 in recursive_edit_1 () at keyboard.c:777
#28 0x0000000000525b01 in Frecursive_edit () at keyboard.c:845
#29 0x0000000000523acf in main (argc=2, argv=0x7fff8cc0cd08) at emacs.c:1654
* urxvt hung. rxvt-unicode==9.19-1. Started with daemon: urxvtcd
(gdb) bt
#0 0x00007f1b40226710 in __poll_nocancel () at
../sysdeps/unix/syscall-template.S:81
#1 0x00007f1b3f481232 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2 0x00007f1b3f482d0f in xcb_wait_for_event () from
/usr/lib/x86_64-linux-gnu/libxcb.so.1
#3 0x00007f1b4166d918 in _XReadEvents () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#4 0x00007f1b41655eb1 in XIfEvent () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#5 0x00007f1b4169c764 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#6 0x00007f1b4169d3c0 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#7 0x00007f1b4169d6b1 in _XimRead () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#8 0x00007f1b4168c096 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#9 0x00007f1b4167a2fd in XSetICValues () from
/usr/lib/x86_64-linux-gnu/libX11.so.6
#10 0x00000000004281bf in rxvt_term::im_send_spot() ()
#11 0x000000000041e6d9 in rxvt_term::flush() ()
#12 0x0000000000438640 in ev_invoke_pending() ()
#13 0x000000000043989e in ev_run ()
#14 0x0000000000418e87 in main ()
(gdb)
In addition I'm using scim (input method).
If there's some way in which I can advance the research of this bug, please
tell me. It happens rarely, maybe once a week. I didn't see any pattern.
I tried as a workaround to go up the stack and then forcing „return“ in gdb
but it only crashed or hung again. Tips to unblock apps are welcome.</pre>
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