[Bug 1870508] Re: ubiquity crashed with SIGSEGV in g_type_check_instance_is_a()

[Marcus Tomlinson]

This crash looks to be due to an infinite loop between a child and
parent in atk.

This is what I think is happening:

- The loops begins with a call to atk_component_get_extents() on a gtk
notebook page.

- atk_component_get_extents() then calls iface->get_extents() [1]

- which translates to gtk_notebook_page_accessible_get_extents() [2]

- the gtk notebook page then calls atk_component_get_extents() on it's
child [3]

- where the child's iface->get_extents() translates to
atk_socket_component_real_get_extents() [4]

- in which the child calls atk_component_get_extents() again on its
parent [5]

- - - -

[1]
https://gitlab.gnome.org/GNOME/atk/-/blob/9118d44778e4d3a05810012cdcaa69eb4db2c389/atk/atkcomponent.c#L299

[2]
https://gitlab.gnome.org/GNOME/gtk/-/blob/4ff578db10fe01de662e478ffd5f9ff205e89074/gtk/a11y/gtknotebookpageaccessible.c#L342

[3]
https://gitlab.gnome.org/GNOME/gtk/-/blob/4ff578db10fe01de662e478ffd5f9ff205e89074/gtk/a11y/gtknotebookpageaccessible.c#L325

[4]
https://gitlab.gnome.org/GNOME/atk/-/blob/e7276a0c47a0bd3cfb5654583ca3358ddf51a609/atk/atksocket.c#L104

[5]
https://gitlab.gnome.org/GNOME/atk/-/blob/e7276a0c47a0bd3cfb5654583ca3358ddf51a609/atk/atksocket.c#L198

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubiquity in Ubuntu.
https://bugs.launchpad.net/bugs/1870508

Title:
  ubiquity crashed with SIGSEGV in g_type_check_instance_is_a()

Status in atk1.0 package in Ubuntu:
  Confirmed
Status in ubiquity package in Ubuntu:
  Confirmed

Bug description:
  == Test Case ==
  1. Boot to ubiquity-dm
  2. Enable the screenreader (Alt+Super+S)
  3. Select "Install Ubuntu"
  4. Proceed with all the steps of the installer

  = Actual Result = 
  During installation, when the slideshow is running, this crash occurs.

  
  ProblemType: Crash
  DistroRelease: Ubuntu 20.04
  Package: ubiquity 20.04.9
  ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27
  Uname: Linux 5.4.0-21-generic x86_64
  NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
  ApportVersion: 2.20.11-0ubuntu22
  Architecture: amd64
  CasperVersion: 1.442
  CurrentDesktop: ubuntu:GNOME
  Date: Fri Apr  3 10:55:58 2020
  ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
  ExecutableTimestamp: 1585729537
  InstallCmdLine: file=/cdrom/preseed/ubuntu.seed initrd=/casper/initrd quiet splash --- maybe-ubiquity
  InterpreterPath: /usr/bin/python3.8
  LiveMediaBuild: Ubuntu 20.04 LTS "Focal Fossa" - Beta amd64 (20200402)
  ProcCmdline: /usr/bin/python3 /usr/lib/ubiquity/bin/ubiquity --greeter --only
  ProcCwd: /
  ProcEnviron:
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=C.UTF-8
  Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu1
  PythonDetails: N/A
  SegvAnalysis:
   Segfault happened at: 0x7fbd15f8f16a <g_type_check_instance_is_a+186>:	mov    %rax,-0x20(%rsp)
   PC (0x7fbd15f8f16a) ok
   source "%rax" ok
   destination "-0x20(%rsp)" (0x7ffe329d3ff0) not located in a known VMA region (needed writable region)!
  SegvReason: writing unknown VMA
  Signal: 11
  SourcePackage: ubiquity
  StacktraceTop:
   g_type_check_instance_is_a () from /lib/x86_64-linux-gnu/libgobject-2.0.so.0
   atk_component_get_extents () from /lib/x86_64-linux-gnu/libatk-1.0.so.0
   ?? () from /lib/x86_64-linux-gnu/libgtk-3.so.0
   atk_component_get_extents () from /lib/x86_64-linux-gnu/libatk-1.0.so.0
   atk_component_get_extents () from /lib/x86_64-linux-gnu/libatk-1.0.so.0
  Title: ubiquity crashed with SIGSEGV in g_type_check_instance_is_a()
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups:

  separator:

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/atk1.0/+bug/1870508/+subscriptions