Re: [PATCH v2] x86/xen: Return from panic notifier

From: JÃrgen GroÃ
Date: Fri Oct 04 2019 - 00:37:57 EST


On 03.10.19 20:12, Boris Ostrovsky wrote:
Currently execution of panic() continues until Xen's panic notifier
(xen_panic_event()) is called at which point we make a hypercall that
never returns.

This means that any notifier that is supposed to be called later as
well as significant part of panic() code (such as pstore writes from
kmsg_dump()) is never executed.

There is no reason for xen_panic_event() to be this last point in
execution since panic()'s emergency_restart() will call into
xen_emergency_restart() from where we can perform our hypercall.

Nevertheless, we will provide xen_legacy_crash boot option that will
preserve original behavior during crash. This option could be used,
for example, if running kernel dumper (which happens after panic
notifiers) is undesirable.

Reported-by: James Dingwall <james@xxxxxxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>


Juergen