Sometimes, non-ramfs initrd root are useful. Eg, for kdump, because
initramfs is memory consuming, so mount a compressed image in earlier
initrd, chroot into it then let systemd do the rest of job is a good
solution.
But systemd doesn't recognize the initrd environment if rootfs is not a
temporary fs. This is a reasonable check, because switch-root in initrd
will wipe the whole rootfs, will be a disaster if there are any
misdetect.
So extend SYSTEMD_IN_INITRD environment variable, now it accepts boolean
value and two extra keyword, "auto" and "lenient". "auto" is same as
before, and it's the default value. "lenient" will let systemd bypass
the rootfs check.
commit f00c36641a enabled
crash_kexec_post_notifiers by default regardless of whether pstore
is enabled or not.
The original intention to enabled this option by default is that
it only affects kernel post-panic behavior, so should have no harm.
But this is not true if the user wants a reliable kdump.
crash_kexec_post_notifiers is known to cause problem with kdump,
and it's documented in kernel. It's not easy to fix the problem
because of how kdump works. Kdump expects the crashed kernel to
jump to an pre-loaded crash kernel, so doing any extra job before
the jump will increase the risk.
It depends on the user to choose between having a reliable kdump or
some other post-panic debug mechanic.
So it's better to keep this config untouched by default, or it may put
kdump at higher risk of failing silently. User should enable it by
uncommenting the config line manually if pstore is always needed.
Also add a inline comment inform user about the potential issue.
Thanks to Dave Young for finding out this issue.
Fixes#16661
Signed-off-by: Kairui Song <kasong@redhat.com>
Kairui Song