** Changed in: linux (Ubuntu)
Status: Incomplete => Triaged
** Changed in: makedumpfile (Ubuntu)
Status: New => Triaged
** Changed in: makedumpfile (Ubuntu)
Assignee: (unassigned) => Thadeu Lima de Souza Cascardo (cascardo)
--
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/1728115
Title:
crashkernel offset prevents kernel boot
Status in linux package in Ubuntu:
Triaged
Status in makedumpfile package in Ubuntu:
Triaged
Bug description:
The linux kernel won't boot when crashkernel parameter tells it to
load a crash kernel at 32Mi on ppc64el on artful.
This happens because the artful kernel is too big. In fact, multiple
requirements on the architecture lead to that:
Kernel memory at address 0 is reserved.
crashkernel must be at first RMO, so architecture puts it at 128Mi. However,
kdump-tools currently puts it at @32Mi because of bug
https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1567539.
PACA and LPPACA need to be at the first RMO as well, and with 2048 CPUs, they
take more than 5MB and 2MiB, respectively.
With the kernel now taking around 25MB from stext to _end, the kernel
can't reserve enough memory for PACA or LPPACA right after boot, and
it panics.
So, right after installing kdump-tools on artful, and rebooting, the
kernel won't boot, with no sign of life as we haven't even started any
console. Investigation for this issue took an entire day.
The fix would be setting the loading address to 128MiB, and start
reducing size of PACA and maybe remove some of the requirements for
the location of PACA and crash kernel.
I would not even set the loading address of the crash kernel in the
parameter itself, and leave it to the kernel to decide it, which it
already does and already would put it at 128Mi.
Cascardo.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1728115/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
