Comment 5 for bug 1908090

I was/am unsure as to which package determines the crashkernel= settings. If it is another package, then by all means please update accordingly.
Thanks,
eric

________________________________
From: <email address hidden> <email address hidden> on behalf of Todd Taft <email address hidden>
Sent: Thursday, July 1, 2021 2:51 AM
To: Eric DeVolder <email address hidden>
Subject: [Bug 1908090] Re: ubuntu 20.04 kdump fails

Are you sure you have this bug filed against the correct package?

At a glance, it looks like you should file it against linux-meta (see
https://packages.ubuntu.com/focal/linux-crashdump )

kexec-tools "provides tools to load a kernel into memory and then "reboot"
 directly into that kernel using the kexec system call, bypassing the normal
 boot process."

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Title:
  ubuntu 20.04 kdump fails

Status in kexec-tools package in Ubuntu:
  Confirmed

Bug description:
  When linux-crashdump (5.4.0.58.61) is enabled on Ubuntu 20.04 LTS,
  everything appears to be in good working order, according to
  "systemctl status kdump-tools" and "kdump-config status". However,
  upon an actual crash, the system hangs, and no crash files are
  produced. I've investigated and have learned that the capture kernel
  does indeed start, but it is unable to unpack the rootfs/initrd, and
  thus fails and hangs.

  [ 1.070469] Trying to unpack rootfs image as initramfs...
  [ 1.333182] swapper/0 invoked oom-killer: gfp_mask=0x100cc2(GFP_HIGHUSER), order=0, oom_score_adj=0
  [ 1.335074] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-26-generic #30-Ubuntu
  [ 1.336396] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  [ 1.336396] Call Trace:
  [ 1.336396] dump_stack+0x6d/0x9a
  [ 1.336396] dump_header+0x4f/0x1eb
  [ 1.336396] out_of_memory.part.0.cold+0x39/0x83
  [ 1.336396] out_of_memory+0x6d/0xd0
  ...
  [ 1.413202] ---[ end Kernel panic - not syncing: System is deadlocked on memory ]---

  On this system with 8G of memory, the crash memory as specified on the kernel command line is "crashkernel=512M-:192M". I changed the 192M to 256M, and now kdump works.

  Not sure how the 192M value is chosen, but it does not work. I think
  this used value used to work for 16.04 and maybe 18.04 (I didn't try),
  but is no longer useful for 20.04.

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