[Bug 915626] Re: usb-creator-gtk crashed with SIGSEGV in _dbus_watch_invalidate

[spencerrecneps]

Apologies if I go on a bit of a rant, but this bug has persisted across
multiple releases for me and, judging by the number of duplicates and
the number of forum postings that I see on this topic, it seems rather
ridiculous that this hadn't been addressed. Is there some technical
reason for this bug? Not being a programmer, I can't comment on the
difficulty of solving the problem, but it sure seems like such a
critical bug in what is probably some people's first introduction to
Ubuntu should not be persisting for this long.

Imagine the following conversation:
"Hey, do you want to try Ubuntu? I can throw it onto a USB stick and let you give it a try."
"Sure."
"Hmm, it looks like I'm having some trouble creating the USB stick. Hang on, let me Google around a bit to see if I can figure out why it keeps crashing."
-- after 2-3 minutes of looking for a fix --
"Never mind, if Ubuntu requires this much work I don't have time."

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https://bugs.launchpad.net/bugs/915626

Title:
  usb-creator-gtk crashed with SIGSEGV in _dbus_watch_invalidate

Status in “dbus” package in Ubuntu:
  Confirmed
Status in “udisks” package in Ubuntu:
  Confirmed
Status in “usb-creator” package in Ubuntu:
  Triaged
Status in “dbus” source package in Quantal:
  Confirmed
Status in “udisks” source package in Quantal:
  Confirmed
Status in “usb-creator” source package in Quantal:
  Won't Fix

Bug description:
  To reproduce:
  Fairly reliably reproducible with ubuntu-12.10-desktop-i386.iso or raring-desktop-i386.iso and choosing persitence on a 12.10/raring amd64 system.

  Traceback:
  Program received signal SIGSEGV, Segmentation fault.
  _dbus_watch_invalidate (watch=0x0) at ../../dbus/dbus-watch.c:171
  171     ../../dbus/dbus-watch.c: No such file or directory.

  #0  _dbus_watch_invalidate (watch=0x0) at ../../dbus/dbus-watch.c:171
  No locals.
  #1  0x00007ffff5dec93d in free_watches (transport=transport at entry=0xf12590) at ../../dbus/dbus-transport-socket.c:83
          socket_transport = 0xf12590
  #2  0x00007ffff5dec9a9 in socket_disconnect (transport=0xf12590) at ../../dbus/dbus-transport-socket.c:987
          socket_transport = 0xf12590
  #3  0x00007ffff5debd67 in _dbus_transport_disconnect (transport=0xf12590) at ../../dbus/dbus-transport.c:509
  No locals.
  #4  _dbus_transport_disconnect (transport=0xf12590) at ../../dbus/dbus-transport.c:500
  No locals.
  #5  0x00007ffff5dec595 in _dbus_transport_queue_messages (transport=0xf12590) at ../../dbus/dbus-transport.c:1165
          status = <optimised out>
  #6  0x00007ffff5dd48e4 in _dbus_connection_get_dispatch_status_unlocked (connection=0xf152b0) at ../../dbus/dbus-connection.c:4211
  No locals.

  It seems to be that NULL is passed to _dbus_watch_invalidate. And that
  function does not assert it's input. In the past this caused to crash
  tomboy (bug #1043887), evalution-data-server (bug #852342) and
  possible other software (e.g.
  https://bugzilla.redhat.com/show_bug.cgi?id=553601 ).

  I'd like to open dbus bug and fix that function in dbus to be more
  resilient.

  Attaching full gdb tracelog: https://bugs.launchpad.net/ubuntu/+source
  /usb-creator/+bug/915626/+attachment/3480179/+files/gdb-dbus.txt

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