xterm segfaults when run via panel launcher

[John Clarke]

Binary package hint: xterm

Package: xterm-229-1ubuntu1
Description: Ubuntu 8.04.1
Release: 8.04

When started from a panel launcher, xterm segfaults shortly after startup at least 50% of the time. When run from the command line, it always seems to work. The launcher was created with Add to Panel/Custom Application Launcher/Command=xterm. Additional arguments to xterm do not seem to affect whether or not it crashes.

I'm running Hardy i386 on a Core2Duo. I also experienced similar failure to launch from xterm on Gutsy, on this same PC and on another PC.

This appears in /var/log/syslog each time:

Aug 15 13:36:12 loki kernel: [66796.742525] xterm[18595]: segfault at 00044c10 eip 08077dbd esp bf9b4dc0 error 4

(esp varies but the other addresses are always the same).

No core dump is produced (ulimit -c is unlimited and a simple test app which does "*(int*)0=0" does produce a core file), nor is there a crash log in /var/crash (apport is enabled).

Changing the launcher command to run strace produced the attached log.

Downloading the source package & rebuilding with debugging enabled gave me a core dump. The crash is at line 1684 of util.c in handle_translated_exposure():

    (gdb) where
    #0 0x08082722 in handle_translated_exposure (xw=0x80c7478, rect_x=0, rect_y=0, rect_width=499,
        rect_height=316) at ../util.c:1684
    #1 0x08082346 in HandleExposure (xw=0x80c7478, event=0xbfe29838) at ../util.c:1598
    #2 0x0805aac4 in VTExpose (w=0x80c7478, event=0xbfe29838, region=0x0) at ../charproc.c:4803
    #3 0x08073a36 in Redraw () at ../misc.c:1119
    #4 0x0807da6e in ScrollBarOn (xw=0x80c7478, init=0, doalloc=1) at ../scrollbar.c:488
    #5 0x0805db1f in VTRealize (w=0x80c7478, valuemask=0xbfe299d8, values=0xbfe2998c)
        at ../charproc.c:6250
    #6 0xb7e5db71 in ?? () from /usr/lib/libXt.so.6
    #7 0xb7e5dcfa in ?? () from /usr/lib/libXt.so.6
    #8 0xb7e5df9e in XtRealizeWidget () from /usr/lib/libXt.so.6
    #9 0x0805af82 in VTInit () at ../charproc.c:4976
    #10 0x0806cc2d in spawnXTerm (xw=0x80c7478) at ../main.c:3245
    #11 0x0806be0e in main (argc=0, argv=0xbfe2a918) at ../main.c:2289

Line 1684 is:

    leftcol = x0 / CurFontWidth(screen, screen->cur_row);

screen is a valid pointer and much of what it points to looks sensible, but screen->visbuf (used by CurFontWidth) does not point to a readable memory location:

    (gdb) x/32x screen->visbuf
    0x44c00: Cannot access memory at address 0x44c00

[John Clarke (jrc61)]

xterm binary rebuilt with debugging enabled.

[John Clarke (jrc61)]

core dump.

[Bryce Harrington (bryce)]

[This is an automated message]

Hi jrc61,

Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering is this still an issue for you? Can you try with the latest development release of Ubuntu? (ISOs are available from cdimage.ubuntu.com)

If it remains an issue, could you also attach a new /var/log/Xorg.0.log?
Thanks in advance.

Please attach the output of `lspci -vvnn` too.

[John Clarke (jrc61)]

This appears to have been fixed in Intrepid (xterm-235-1ubuntu1.1). I've launched a couple of hundred xterms from the panel and they've all started correctly. You can close this bug, thanks.

[Bryce Harrington (bryce)]

Great, thanks for letting us know.

[Jeff Powell (jeffp-bangtherockstogether)]

Any chance of getting this fix made available in 8.04? I'm seeing this problem too and would like to see an official patch if possible. Thanks.

[Joshua Nekl (joshuanekl)]

This bug still exists in 8.04.

When xterm starts from the launcher, the window dies 50% of the time. When started from the command-line, I see it segfault just as frequently.

$ lsb_release -rd
Description: Ubuntu 8.04.3 LTS
Release: 8.04

$ dpkg-query -l xterm
||/ Name Version Description
ii xterm 229-1ubuntu1.1 X terminal emulator

[Thomas Dickey (dickey-his)]

The previous comment stated that it was assumed to be fixed in #235.
This comment repeats the original report against #229.
(The current version is #248).

[Joshua Nekl (joshuanekl)]

Sorry, I'm not up-and-up on ubuntu policies and procedures.
I understand this bug was fixed with xterm version 235 on Intrepid, but it is still broken in the version of xterm included in ubuntu 8.04 Hardy. I gather that I should have nominated this bug for release then?

[Thomas Dickey (dickey-his)]

No - since there's no fix released for 8.04 Hardy. But it's certainly not a "New", since there's
previous history which tends to make it "Confirmed". (There's no progress on it in this release).

[Joshua Nekl (joshuanekl)]

I think this may be related to bug # 199285.
I've found that if I turn off desktop effects System->Preferences->Appearance->Visual Effects=None, the problem goes away. If I pull up xterms remotely using Xming, xterm never crashes on startup.

[Bryce Harrington (bryce)]

Bugs are closed in Ubuntu source packages when they are closed in the development version. If the bug exists in prior versions of Ubuntu the proper procedure is to nominate the bug for that release.

[Rolf Leggewie (r0lf)]

Hardy has seen the end of its life and is no longer receiving any updates. Marking the Hardy task for this ticket as "Won't Fix".