Re: [PATCH v1 1/3] liveupdate: skip serialization for context-preserving kexec

[Pasha Tatashin <pasha.tatashin@soleen.com>]

On 05-06 10:31, Pratyush Yadav wrote:
> Hi Pasha,
> 
> On Wed, May 06 2026, Pasha Tatashin wrote:
> 
> > A preserve_context kexec returns to the current kernel, which
> > is unrelated to live update where the state is passed to the next
> > kernel. Skip liveupdate_reboot() in this case to avoid serialization
> > and prevent sessions from being left in a frozen state upon return.
> 
> Should we also stop KHO? Now it is stateless and always finalized. I am

No. KHO preserves kernel internal memory; for context-preserved 
kexec, the 2nd kernel and the 1st kernel do not have overlapping 
memory. So, whatever the 1st kernel maintains in KHO is an internal 
detail of the 1st kernel. Once we return from the 2nd kernel to the 1st 
kernel, all KHO memory is going to stay as-is, and the 1st kernel can 
even perform a regular kexec or live update later.

Pasha

> not sure how these kexec jump images will interact with KHO data, but
> seems like we shouldn't be handing over memory if the image will jump
> back.
> 
> Anyway, for this patch:
> 
> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
> 
> >
> > Fixes: db8bed8082dc ("kexec: call liveupdate_reboot() before kexec")
> > Reported-by: Oskar Gerlicz Kowalczuk <oskar@gerlicz.space>
> > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> [...]
> 
> -- 
> Regards,
> Pratyush Yadav