------- Comment From mihaj...@de.ibm.com 2020-10-14 07:51 EDT-------
Sorry for not responfing earlier. After installing a new system I can see that 
the update happening:

$ cat /proc/cmdline
root=/dev/mapper/vgubuntu-root 
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M

However it still turns out that - if using an encrypted volume - it's
not possible to unlock the volume from the kdump kernel for a ~2GB VM as
the 320MB are still not sufficient.

Bumping the VM memory to 4GB will allow the kdump kernel to unlock the
volume.

I think that either 512M should be the lowest value used for the
crashkernel, or at least a warning should be emitted, alerting the
system administrator that for a < 4GB machine kdump is not going to work
with an encrypted root/dump volume.

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You received this bug notification because you are a member of Kernel
Packages, which is subscribed to makedumpfile in Ubuntu.
https://bugs.launchpad.net/bugs/1877533

Title:
  [20.10 FEAT] Increase the crashkernel setting if the root volume is
  luks2-encrypted

Status in Ubuntu on IBM z Systems:
  In Progress
Status in linux package in Ubuntu:
  Invalid
Status in makedumpfile package in Ubuntu:
  In Progress
Status in linux source package in Focal:
  Invalid
Status in makedumpfile source package in Focal:
  In Progress
Status in linux source package in Groovy:
  Invalid
Status in makedumpfile source package in Groovy:
  In Progress

Bug description:
  Description:
  In case the volume containing the root filesystem is encrypted using LUKS2 
the memory used while unlocking the volume may exceed the size allocated to the 
kdump kernel. This will lead to a failure while processing kdump and the dump 
file will not be stored. Unfortunately, this condition may not be detected by a 
client before a problem occurs.
  The request is to have the kdump package installation script check for LUKS2 
encryption (more precisely for Argon2i PBKDF, which is the root cause of the 
high memory usage). If the condition is met, the installation procedure should 
increase the crashkernel parameter to a higher value (>=512M)or issue a 
warning, if the system memory is insufficient to reserve enough crashkernel 
memory.

  Business Case:
  Pervasive Encryption and Secure Execution require encryption of the 
filesystems in order to keep customer data secure at all times. With the 
increasing usage of these technologies, the number of kdump will rise too, 
typically at inconvenient times, when the kdump is triggered due to a real 
customer issue.
  With the suggested change, the number of customer complaints and effort to 
handle them will be reduced.

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