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[Bug 1366754] [NEW] kdump does not work with encrypted root partition

 

Public bug reported:

I have my root partition encrypted using dm-crypt.
I could not get kdump working with the encrypted root partition, the computer simply hangs forever and will never reboot. (I tried the same kdump and grub settings on an identical install without encrypted root on the same machine and everything worked fine there.)

No errors are shown on the screen, when I trigger a panic from an x
session since the display is simply frozen and nothing will happen. I
guess the crash kernel expects the luks password and therefore will wait
for the password forever. I tried to blindly type in my password, but I
have never succeeded.

I can imagine 2 ways this bug could be solved:

1.) the password for the root partition could be passed from the primary kernel to the crash kernel during load time
This is discussed here: https://bugzilla.redhat.com/show_bug.cgi?id=1028397 in comment #9:
"One could argue that password could be passed to second kernel in bootparams
during load time. But this is very unconventional and first requires the work
I am doing to implement a new kexec syscall which prepares bootparam in kernel (as opposed to user space).
So in long term may be there is a case that pass credentials from old kernel to new kernel using bootparams. But don't expect anything soon."

2.) kdump allows dumping to an external partition that is not encrypted
without mounting the root partition, such as the /boot partition.

Another redhat bug report where something similar is discussed:
https://bugzilla.redhat.com/show_bug.cgi?id=1053045.

** Affects: makedumpfile (Ubuntu)
     Importance: Medium
     Assignee: Louis Bouchard (louis-bouchard)
         Status: Triaged

** Package changed: kexec-tools (Ubuntu) => makedumpfile (Ubuntu)

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https://bugs.launchpad.net/bugs/1366754

Title:
  kdump does not work with encrypted root partition

Status in “makedumpfile” package in Ubuntu:
  Triaged

Bug description:
  I have my root partition encrypted using dm-crypt.
  I could not get kdump working with the encrypted root partition, the computer simply hangs forever and will never reboot. (I tried the same kdump and grub settings on an identical install without encrypted root on the same machine and everything worked fine there.)

  No errors are shown on the screen, when I trigger a panic from an x
  session since the display is simply frozen and nothing will happen. I
  guess the crash kernel expects the luks password and therefore will
  wait for the password forever. I tried to blindly type in my password,
  but I have never succeeded.

  I can imagine 2 ways this bug could be solved:

  1.) the password for the root partition could be passed from the primary kernel to the crash kernel during load time
  This is discussed here: https://bugzilla.redhat.com/show_bug.cgi?id=1028397 in comment #9:
  "One could argue that password could be passed to second kernel in bootparams
  during load time. But this is very unconventional and first requires the work
  I am doing to implement a new kexec syscall which prepares bootparam in kernel (as opposed to user space).
  So in long term may be there is a case that pass credentials from old kernel to new kernel using bootparams. But don't expect anything soon."

  2.) kdump allows dumping to an external partition that is not
  encrypted without mounting the root partition, such as the /boot
  partition.

  Another redhat bug report where something similar is discussed:
  https://bugzilla.redhat.com/show_bug.cgi?id=1053045.

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Follow ups

References