X crashes during gesture

[Massimiliano Mirra]

I'm using touchegg for multi-touch gestures. Often (as in, a few times per day) during a gesture X crashes:

[ 42277.720] (EE)
[ 42277.721] (EE) Backtrace:
[ 42277.724] (EE) 0: /usr/bin/Xorg.bin (xorg_backtrace+0x56) [0x593a46]
[ 42277.724] (EE) 1: /usr/bin/Xorg.bin (0x400000+0x197b99) [0x597b99]
[ 42277.724] (EE) 2: /usr/lib/libc.so.6 (0x7f2a43de5000+0x339f0) [0x7f2a43e189f0]
[ 42277.724] (EE) 3: /usr/bin/Xorg.bin (0x400000+0xecc48) [0x4ecc48]
[ 42277.724] (EE) 4: /usr/bin/Xorg.bin (_CallCallbacks+0x34) [0x43cb64]
[ 42277.724] (EE) 5: /usr/bin/Xorg.bin (XaceHook+0x101) [0x4eb761]
[ 42277.725] (EE) 6: /usr/bin/Xorg.bin (0x400000+0x11e7d8) [0x51e7d8]
[ 42277.725] (EE) 7: /usr/bin/Xorg.bin (0x400000+0x11fa12) [0x51fa12]
[ 42277.725] (EE) 8: /usr/bin/Xorg.bin (0x400000+0x122a99) [0x522a99]
[ 42277.725] (EE) 9: /usr/bin/Xorg.bin (0x400000+0x144fc2) [0x544fc2]
[ 42277.725] (EE) 10: /usr/bin/Xorg.bin (0x400000+0x174ffa) [0x574ffa]
[ 42277.725] (EE) 11: /usr/bin/Xorg.bin (mieqProcessInputEvents+0x127) [0x5751d7]
[ 42277.726] (EE) 12: /usr/bin/Xorg.bin (ProcessInputEvents+0x19) [0x475ad9]
[ 42277.726] (EE) 13: /usr/bin/Xorg.bin (0x400000+0x375f5) [0x4375f5]
[ 42277.726] (EE) 14: /usr/bin/Xorg.bin (0x400000+0x3b866) [0x43b866]
[ 42277.726] (EE) 15: /usr/lib/libc.so.6 (__libc_start_main+0xf0) [0x7f2a43e05040]
[ 42277.726] (EE) 16: /usr/bin/Xorg.bin (0x400000+0x25d0e) [0x425d0e]
[ 42277.726] (EE) [ 42277.720] (EE)
[ 42277.721] (EE) Backtrace:
[ 42277.724] (EE) 0: /usr/bin/Xorg.bin (xorg_backtrace+0x56) [0x593a46]
[ 42277.724] (EE) 1: /usr/bin/Xorg.bin (0x400000+0x197b99) [0x597b99]
[ 42277.724] (EE) 2: /usr/lib/libc.so.6 (0x7f2a43de5000+0x339f0) [0x7f2a43e189f0]
[ 42277.724] (EE) 3: /usr/bin/Xorg.bin (0x400000+0xecc48) [0x4ecc48]
[ 42277.724] (EE) 4: /usr/bin/Xorg.bin (_CallCallbacks+0x34) [0x43cb64]
[ 42277.724] (EE) 5: /usr/bin/Xorg.bin (XaceHook+0x101) [0x4eb761]
[ 42277.725] (EE) 6: /usr/bin/Xorg.bin (0x400000+0x11e7d8) [0x51e7d8]
[ 42277.725] (EE) 7: /usr/bin/Xorg.bin (0x400000+0x11fa12) [0x51fa12]
[ 42277.725] (EE) 8: /usr/bin/Xorg.bin (0x400000+0x122a99) [0x522a99]
[ 42277.725] (EE) 9: /usr/bin/Xorg.bin (0x400000+0x144fc2) [0x544fc2]
[ 42277.725] (EE) 10: /usr/bin/Xorg.bin (0x400000+0x174ffa) [0x574ffa]
[ 42277.725] (EE) 11: /usr/bin/Xorg.bin (mieqProcessInputEvents+0x127) [0x5751d7]
[ 42277.726] (EE) 12: /usr/bin/Xorg.bin (ProcessInputEvents+0x19) [0x475ad9]
[ 42277.726] (EE) 13: /usr/bin/Xorg.bin (0x400000+0x375f5) [0x4375f5]
[ 42277.726] (EE) 14: /usr/bin/Xorg.bin (0x400000+0x3b866) [0x43b866]
[ 42277.726] (EE) 15: /usr/lib/libc.so.6 (__libc_start_main+0xf0) [0x7f2a43e05040]
[ 42277.726] (EE) 16: /usr/bin/Xorg.bin (0x400000+0x25d0e) [0x425d0e]
[ 42277.726] (EE)
[ 42277.726] (EE) Segmentation fault at address 0x50
[ 42277.727] (EE)
Fatal server error:
[ 42277.727] (EE) Caught signal 11 (Segmentation fault). Server aborting
[ 42277.727] (EE)
[ 42277.727] (EE)

[ 42277.726] (EE) Segmentation fault at address 0x50
[ 42277.727] (EE)
Fatal server error:
[ 42277.727] (EE) Caught signal 11 (Segmentation fault). Server aborting
[ 42277.727] (EE)
[ 42277.727] (EE)

    $ pacman -Q xorg-server geis grail frame
    xorg-server 1.16.1-1
    geis 2.2.16-1
    grail 3.1.0-1
    frame 2.5.0-1
    $ uname -r
    3.17.1-1-ARCH
    $ yaourt -Q touchegg-svn
    local/touchegg-svn 191-1

Can I do anything to further debug this?

Bug reported to touchegg already: https://code.google.com/p/touchegg/issues/detail?id=250

[Stephen M. Webb (bregma)]

This is a crash in the X11 server. It looks like a crash we used to see years ago in older versions of the x.org X11 server. What OS and release are you running? What version of x.org do you have installed?

[Massimiliano Mirra (bard-hyperstruct)]

System is Arch, up to date (but the issue has been present since I first installed touchegg a few months ago).

$ uname -r
3.17.1-1-ARCH

$ Xorg -version

X.Org X Server 1.16.1
Release Date: 2014-09-21
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.16.1-1-ARCH x86_64
Current Operating System: Linux arrow 3.17.1-1-ARCH #1 SMP PREEMPT Wed Oct 15 15:04:35 CEST 2014 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-linux root=UUID=d8f6031b-ec59-4a37-9757-6bc2a519b0b7 rw quiet
Build Date: 21 September 2014 10:53:13AM

$ pacman -Q geis grail frame
    geis 2.2.16-1
    grail 3.1.0-1
    frame 2.5.0-1

[Massimiliano Mirra (bard-hyperstruct)]

Any clues? Bug still present and leading to Xorg crash with the following:

$ uname -r
3.18.6-1-ARCH

$ Xorg -version
X.Org X Server 1.17.1
Release Date: 2015-02-10
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.18.6-1-ARCH x86_64
[...]

$ pacman -Q geis grail frame
geis 2.2.16-1
grail 3.1.0-1
frame 2.5.0-1

[Sebastian (seb443556)]

I noticed a similar behaviour. I have an application which uses xmessage with buttons. So everytime I press a button in the window, it opens a new window with xmessage with different text and buttons. If I use the touchscreen to press the buttons, it sometimes (rarely) happens that xorg chrashes. The crash only happens if I have touchegg running in the background. I get the following reports:

in syslog:
org.a11y.atspi.Registry[1112]: XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0"

in Xorg.o.log:
Segmentation fault at address 0x...
Fatal server error:
Caught signal 11 (Segmentation fault). Server aborting

in touchegg:
touchegg: Fatal IO error: client killed

I was able to reproduce the crash reliably by using the following script:
#!/bin/bash
while :
do
xmessage -center "test bla bla bla" -buttons "" &
testpid=$!
sleep 0.1
kill $testpid
done

If I now start touching around in the area of the appearing test window (only normal single taps and/or swipes, no gestures) the xorg crashes immediately. If I kill touchegg before doing this, no crashes appear.

Ubuntu 16.04 LTS
Xorg Version 1.18.3
Intel Atom Processor E3827

[Sebastian (seb443556)]

I executed the following steps, maybe this helps:

1. attach gdb to xfwm4
2. set breakpoint on _exit
3. continue
4. provoke crash
5. dump stack

(gdb) bt
#0 0xb6ae56e8 in _exit () at ../sysdeps/unix/sysv/linux/i386/_exit.S:24
#1 0xb6a6392a in __run_exit_handlers (status=1, listp=0xb6be73dc <__exit_funcs>, run_list_atexit=true) at exit.c:97
#2 0xb6a639cf in __GI_exit (status=1) at exit.c:104
#3 0xb718c537 in gdk_x_io_error (display=0x80d60c00) at /build/gtk+2.0-LJ3oCC/gtk+2.0-2.24.30/gdk/x11/gdkmain-x11.c:544
#4 0xb6cbf2ed in _XIOError (dpy=0x80d60c00) at ../../src/XlibInt.c:1464
#5 0xb6cbd362 in _XReply (dpy=0x80d60c00, rep=0xbffb8c4c, extra=0, discard=1) at ../../src/xcb_io.c:708
#6 0xb6ca3670 in _XGetWindowAttributes (dpy=0x80d60c00, w=20971564, attr=0x80dedb7c) at ../../src/GetWAttrs.c:114
#7 0xb6ca37c8 in XGetWindowAttributes (dpy=0x80d60c00, w=20971564, attr=0x80dedb7c) at ../../src/GetWAttrs.c:149
#8 0x8011031d in add_win (display_info=0x80d95370, id=20971564, c=0x0) at compositor.c:2143
#9 0x801125a5 in compositorHandleEvent (ev=0xbffb8f4c, display_info=0x80d95370) at compositor.c:2747
#10 0x801125a5 in compositorHandleEvent (display_info=0x80d95370, ev=0xbffb8f4c) at compositor.c:3227
#11 0x80117931 in xfwm4_event_filter (ev=0xbffb8f4c, display_info=0x80d95370) at events.c:2283
#12 0x80117931 in xfwm4_event_filter (xevent=0xbffb8f4c, data=0x80d95370) at events.c:2297
#13 0x80116069 in eventXfwmFilter (gdk_xevent=0xbffb8f4c, event=0x80de58c0, data=0x80ddcd38) at event_filter.c:158
#14 0xb71822c4 in gdk_event_apply_filters (xevent=xevent@entry=0xbffb8f4c, event=event@entry=0x80de58c0, window=window@entry=0x0)
    at /build/gtk+2.0-LJ3oCC/gtk+2.0-2.24.30/gdk/x11/gdkevents-x11.c:371
#15 0xb71835cc in gdk_event_translate (display=display@entry=0x80d6c0a0 [GdkDisplayX11], event=event@entry=0x80de58c0, xevent=xevent@entry=0xbffb8f4c, return_exposes=0) at /build/gtk+2.0
-LJ3oCC/gtk+2.0-2.24.30/gdk/x11/gdkevents-x11.c:969
#16 0xb7184ec9 in _gdk_events_queue (display=0x80d6c0a0 [GdkDisplayX11]) at /build/gtk+2.0-LJ3oCC/gtk+2.0-2.24.30/gdk/x11/gdkevents-x11.c:2358
#17 0xb7184f7e in gdk_event_dispatch (source=0x80d73688, callback=0x0, user_data=0x0)
    at /build/gtk+2.0-LJ3oCC/gtk+2.0-2.24.30/gdk/x11/gdkevents-x11.c:2419
#18 0xb6e23e29 in g_main_context_dispatch (context=0x80d73758) at /build/glib2.0-Spm2To/glib2.0-2.48.0/./glib/gmain.c:3154
#19 0xb6e23e29 in g_main_context_dispatch (context=0x80d73758) at /build/glib2.0-Spm2To/glib2.0-2.48.0/./glib/gmain.c:3769
#20 0xb6e240c9 in g_main_context_iterate (context=0x80d73758, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/glib2.0-Spm2To/glib2.0-2.48.0/./glib/gmain.c:3840
#21 0xb6e24479 in g_main_loop_run (loop=0x80dc5350) at /build/glib2.0-Spm2To/glib2.0-2.48.0/./glib/gmain.c:4034
#22 0xb7310485 in IA__gtk_main () at /build/gtk+2.0-LJ3oCC/gtk+2.0-2.24.30/gtk/gtkmain.c:1282
#23 0x80106d05 in main (argc=1, argv=0xbffb92a4) at main.c:693