Comment 1 for bug 1889190

18.04->20.04 upgrade breaks with the reproducer:

...

Preparing to unpack .../libc6_2.31-0ubuntu9_amd64.deb ...

Progress: [ 38%]
ldconfig: wrapper deferring update (trigger activated)
Checking for services that may need to be restarted...
Checking init scripts...
Checking for services that may need to be restarted...
Checking init scripts...
dpkg: error processing archive /var/cache/apt/archives/libc6_2.31-0ubuntu9_amd64.deb (--unpack):
 new libc6:amd64 package pre-installation script subprocess returned error exit status 20
Selecting previously unselected package libcrypt1:amd64.
dpkg: considering deconfiguration of libc6:amd64, which would be broken by installation of libcrypt1:amd64 ...
dpkg: yes, will deconfigure libc6:amd64 (broken by libcrypt1:amd64)
Preparing to unpack .../libcrypt1_1%3a4.4.10-10ubuntu4_amd64.deb ...
De-configuring libc6:amd64 (2.27-3ubuntu1.2) ...

Progress: [ 44%]
Unpacking libcrypt1:amd64 (1:4.4.10-10ubuntu4) ...
Replacing files in old package libc6:amd64 (2.27-3ubuntu1.2) ...

Progress: [ 50%]
Errors were encountered while processing:
 /var/cache/apt/archives/libc6_2.31-0ubuntu9_amd64.deb
ERROR: Cannot create report: [Errno 17] File exists: '/var/crash/libc6.0.crash'
Exception during pm.DoInstall(): E:Sub-process /usr/bin/dpkg returned an error code (1)

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