[Bug 2015857] Re: Repeatedly unusable truncated crash files

[Benjamin Drung]

Thanks for providing the steps to reproduce. Preparation:

1. Ubuntu 23.04 (lunar) desktop in a VM
2. Remove all crashes: `sudo rm -f /var/crash/*`
3. Downgrade gjs and libgjs0g to 1.76.0-1

Then did your steps. On the first tries the crash file was 49 MB in size
and retracing looks correct. On my last try it only was 14 MB apport-
retrace -g showed following warnings (and backtrace fails):

```
Warnung: Section `.reg-xstate/10527' in core file too small.
Warnung: Error reading shared library list entry at 0x646c747200000000
Failed to read a valid object file image from memory.
Core was generated by `/usr/bin/gnome-shell'.
Program terminated with signal SIGSEGV, Segmentation fault.
Warnung: Section `.reg-xstate/10527' in core file too small.
```

```
$ ls /var/crash/ -alh
insgesamt 12M
drwxrwxrwt  2 root   whoopsie 4,0K Apr 17 15:44 .
drwxr-xr-x 14 root   root     4,0K Mär 29 11:14 ..
-rw-r-----  1 bdrung whoopsie  12M Apr 17 15:44 _usr_bin_gnome-shell.1000.crash
-rw-r-----  1 bdrung whoopsie 376K Apr 17 15:44 _usr_lib_x86_64-linux-gnu_indicator-messages_indicator-messages-service.1000.crash
```

I disabled all processing afterwards to exclude that as reason:

```
sudo systemctl stop whoopsie.path apport-autoreport.path apport-autoreport.timer
```

** Changed in: apport (Ubuntu)
   Importance: Undecided => High

** Changed in: apport (Ubuntu)
       Status: New => Triaged

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https://bugs.launchpad.net/bugs/2015857

Title:
  Repeatedly unusable truncated crash files

Status in apport package in Ubuntu:
  Triaged

Bug description:
  Repeatedly unusable truncated crash files:

  Bug 2012974, bug 2015842, bug 2015140, bug 2012075

  Based on my own testing, the problems seems to happen if multiple
  binaries crash simultaneously (like at logout). One crash file gets
  fully written and the other is incomplete.

  If I remove apport from the equation and just get the kernel to dump
  core files then the core files are always written reliably (should be
  several hundred MB in the case of gnome-shell).

  Running `apport-retrace -g $crash` on the .crash files will fail with
  "/tmp/apport_core_[...] is not a core dump: file format not
  recognized"

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