ggl-gtk crashed with SIGSEGV in ggadget::dbus::DBusProxy::CallMethod()

[Roland Dreier]

Just installed google-gadgets-gtk and selected the google gadgets chooice in the applications menu. Apparently crashed during startup without displaying anything or doing anything I could see.

ProblemType: Crash
Architecture: i386
DistroRelease: Ubuntu 9.04
ExecutablePath: /usr/bin/ggl-gtk
Package: google-gadgets-gtk 0.10.3-1ubuntu1
ProcCmdline: /usr/bin/ggl-gtk
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Signal: 11
SourcePackage: google-gadgets
StacktraceTop:
 ggadget::dbus::DBusProxy::CallMethod ()
 ggadget::framework::linux_system::Machine::Machine ()
 ?? ()
 ?? ()
 _init ()
Title: ggl-gtk crashed with SIGSEGV in ggadget::dbus::DBusProxy::CallMethod()
Uname: Linux 2.6.28-4-generic i686
UserGroups: adm admin floppy fuse

[Apport retracing service (apport)]

StacktraceTop:Machine (this=0xb67e5340)
global constructors keyed to linux_system_framework.cc ()
__do_global_ctors_aux ()
_init ()
call_init () from /lib/ld-linux.so.2

[Roland Dreier (roland.dreier)]

This crash is occurring because ggl-gtk is not able to connect to the DBus system bus and it ends up blindly trying to invoke a method on the uninitialized NULL pointer for its system bus object. In Machine::Machine(), the code calls DBusProxy::NewSystemProxy(), which fails internally (and silently) and just returns NULL, so the first CallMethod() operation gets a SEGV.

I enabled more tracing, and I see that NewSystemProxy is failing when trying to invoke the Ping method on the system bus; the code

      if (dbus_error_is_set(&error))
        DLOG("Failed to retrieve reply from %s|%s, error: %s, %s",
     name_.c_str(), path_.c_str(), error.name, error.message);

in RetrieveReplyMessage() in dbus_proxy.cc prints:

Failed to retrieve reply from org.freedesktop.Hal|/org/freedesktop/Hal/devices/computer, error: org.freedesktop.DBus.Error.AccessDenied, Rejected send message, 1 matched rules; type="method_call", sender=":1.168" (uid=1000 pid=22508 comm="ggl-gtk ") interface="org.freedesktop.DBus.Peer" member="Ping" error name="(unset)" requested_reply=0 destination="org.freedesktop.Hal" (uid=0 pid=3267 comm="/usr/sbin/hald "))

which is not surprising since ggl-gtk is an unprivileged app trying to use the system bus.

[Roland Dreier (roland.dreier)]

It seems that the newer upstream release 0.10.5 has code to check the return value of NewSystemProxy() and continue without crashing. This version is already packaged in the Debian repository, and I tried building it on my Jaunty system. On startup, it prints

  No permissions to access D-Bus.

but at least doesn't crash.

So the best way forward seems to be to merge the 0.10.5 package for Jaunty, since the Ubuntu-specific changes look minimal and easy to merge, and the current 0.10.3 package is completely broken.

[Roland Dreier (roland.dreier)]

I see that 0.10.5-0.1ubuntu1 is now in the archive, which has the fix for this bug. So this bug can probably be marked as resolved now.

[jaduncan (jaduncan)]

Confirmed that this error does not affect me now.

[jaduncan (jaduncan)]

Fix inherited from Debian