On 1/10/2019 12:53 AM, Dave Young wrote:
Hi Kazu,
On 01/09/19 at 03:38pm, Kazuhito Hagio wrote:
> Since early kdump is generally used for capturing vmcore when
> boot-time panic occurs, if a system always reboots after capturing
> vmcore, it can go into a crash loop.
>
> To avoid this issue, this patch add a note on 'final_action' option
> to the early kdump document.
>
> Signed-off-by: Kazuhito Hagio <k-hagio(a)ab.jp.nec.com>
> Cc: Dave Young <dyoung(a)redhat.com>
> Cc: Lianbo Jiang <lijiang(a)redhat.com>
> ---
> early-kdump-howto.txt | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/early-kdump-howto.txt b/early-kdump-howto.txt
> index fe4f13f..6da6220 100644
> --- a/early-kdump-howto.txt
> +++ b/early-kdump-howto.txt
> @@ -1,6 +1,7 @@
> Early Kdump HOWTO
>
> Introduction
> +------------
>
> Kdump service starts too late, so early crashes will have no chance to get
> kdump kernel booting, this will cause crash information to be lost. It is
> @@ -12,7 +13,8 @@ which is disabled by default.
> For the normal kdump service, it can check whether the early kdump has loaded
> the crash kernel and initramfs. It has no conflict with the early kdump.
>
> -How to configure early kdump:
> +How to configure early kdump
> +----------------------------
>
> We assume if you're reading this document, you should already have kexec-tools
> installed.
> @@ -21,6 +23,14 @@ You can rebuild the initramfs with earlykdump support with below
steps:
> 1. start kdump service to make sure kdump initramfs is created.
> # systemctl start kdump
>
> + NOTE: If a crash occurs during boot process, early kdump captures a vmcore
> + and reboot the system by default, so the system might go into crash loop.
> + You can avoid such a crash loop by adding the following settings, which
> + power off the system after dump capturing, to kdump.conf in advance:
> +
> + final_action poweroff
> + default poweroff
'default' can be anything other than "reboot", so it would be better
to
describe it here.
Thank you.
I think "dump_to_rootfs" also might be dangerous in this case,
so will exclude "reboot" and "dump_to_rootfs".
Thanks,
Kazu