[Bug 1751252] Re: [regression] ubiquity crashed in debconf.py:104 with ValueError: invalid literal for int() with base 10: ''

Wed May 2 09:52:12 UTC 2018

Unfortunately I can't tell what in shm_access is failing exactly because
gdb skips straight from shm.c:314 back to the caller. So that suggests
this code path, but I can't verify it:

static int
shm_access(ClientPtr client, SHMPERM_TYPE * perm, int readonly)
{
    int uid, gid;
    mode_t mask;
    int uidset = 0, gidset = 0;
    LocalClientCredRec *lcc;

    if (GetLocalClientCreds(client, &lcc) != -1) {  // FALSE
    ...
    }
    /* Otherwise, check everyone else */
    mask = S_IROTH;
    if (!readonly) {
        mask |= S_IWOTH;
    }
    return (SHMPERM_MODE(perm) & mask) == mask ? 0 : -1;
}

So Xorg _should_ be returning an error, and it is. The problem seems to
be that the client (python3 gtk_ui process) has a real uid=0 and
effective uid=999. So that allows it to connect to Xorg (normally Xorg
rejects root clients), but doesn't allow Xorg to check the client shm
permissions. So Xorg rejects the client's attempt at XShmAttach.

How any of this relates to scale=200% and why it works at 100%, I'm not
sure. We might need to review comment #15 in more detail.

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https://bugs.launchpad.net/bugs/1751252

Title:
  [regression] ubiquity crashed in debconf.py:104 with ValueError:
  invalid literal for int() with base 10: ''

Status in OEM Priority Project:
  Triaged
Status in glib2.0 package in Ubuntu:
  Invalid
Status in ubiquity package in Ubuntu:
  Triaged
Status in glib2.0 source package in Bionic:
  Invalid
Status in ubiquity source package in Bionic:
  Triaged

Bug description:
  The Ubuntu installer crashes on hiDPI machines (QHD/UHD etc). Although
  it was working some weeks/months ago, so this is a recent regression.

  ---

  https://errors.ubuntu.com/problem/82f7f7e7923663c7b2123c7f1f49af29f6ff4d77
  https://errors.ubuntu.com/problem/735a2b847e0eeab6c8a7b954de5110e43889be15
  https://errors.ubuntu.com/problem/dcd4c9da5ee0cc6d36324446e0e49d39705c90b7
  https://errors.ubuntu.com/problem/cb82f70f9ede07369e8104da9ddf87e28b42257d
  https://errors.ubuntu.com/problem/84a5563af3d2b85f098da832ece4cb8450bfd524

  ---

  WORKAROUND:

  1. Boot into the live session.
  2. Settings > Devices > Displays > Scale = 100%
  3. Click Apply.
  4. Proceed with installation: Click "Install Ubuntu 18.04 LTS".

  ---

  Crashed in a VM in the middle of installation. The host is Bionic up
  to date.

  From the journal
  Feb 23 12:52:27 ubuntu kernel: traps: ubiquity[2646] trap int3 ip:7f5a76936961 sp:7ffde5090c50 error:0 in libglib-2.0.so.0.5400.1[7f5a768e6000+111000]
  Feb 23 12:52:41 ubuntu /install.py[6858]: Exception during installation:
  Feb 23 12:52:41 ubuntu /install.py[6858]: Traceback (most recent call last):
  Feb 23 12:52:41 ubuntu /install.py[6858]:   File "/usr/share/ubiquity/install.py", line 757, in <module>
  Feb 23 12:52:41 ubuntu /install.py[6858]:     install.run()
  Feb 23 12:52:41 ubuntu /install.py[6858]:   File "/usr/share/ubiquity/install.py", line 135, in run
  Feb 23 12:52:41 ubuntu /install.py[6858]:     self.copy_all()
  Feb 23 12:52:41 ubuntu /install.py[6858]:   File "/usr/share/ubiquity/install.py", line 505, in copy_all
  Feb 23 12:52:41 ubuntu /install.py[6858]:     self.db.progress('SET', 10 + copy_progress)
  Feb 23 12:52:41 ubuntu /install.py[6858]:   File "/usr/lib/python3/dist-packages/debconf.py", line 83, in <lambda>
  Feb 23 12:52:41 ubuntu /install.py[6858]:     lambda *args, **kw: self.command(command, *args, **kw))
  Feb 23 12:52:41 ubuntu /install.py[6858]:   File "/usr/lib/python3/dist-packages/debconf.py", line 104, in command
  Feb 23 12:52:41 ubuntu /install.py[6858]:     status = int(status)
  Feb 23 12:52:41 ubuntu /install.py[6858]: ValueError: invalid literal for int() with base 10: ''

  ProblemType: Crash
  DistroRelease: Ubuntu 18.04
  Package: ubiquity 18.04.1
  ProcVersionSignature: Ubuntu 4.13.0-32.35-generic 4.13.13
  Uname: Linux 4.13.0-32-generic x86_64
  ApportVersion: 2.20.8-0ubuntu10
  Architecture: amd64
  CasperVersion: 1.388
  Date: Fri Feb 23 12:52:28 2018
  ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
  InstallCmdLine: file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash --- keyboard-configuration/layoutcode=fr keyboard-configuration/variantcode=oss
  InterpreterPath: /usr/bin/python3.6
  LiveMediaBuild: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180222)
  ProcCmdline: /usr/bin/python3 /usr/lib/ubiquity/bin/ubiquity -d
  ProcEnviron:
   TERM=xterm-256color
   PATH=(custom, no user)
   LANG=C.UTF-8
   SHELL=/bin/bash
  Python3Details: /usr/bin/python3.6, Python 3.6.4+, python3-minimal, 3.6.4-1
  PythonDetails: /usr/bin/python2.7, Python 2.7.14+, python-minimal, 2.7.14-4
  Signal: 5
  SourcePackage: ubiquity
  StacktraceTop:
   ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
   ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
   _XEventsQueued () from /usr/lib/x86_64-linux-gnu/libX11.so.6
   XPending () from /usr/lib/x86_64-linux-gnu/libX11.so.6
   ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
  Title: ubiquity crashed with signal 5 in _XEventsQueued()
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups:

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