Messages in this thread |  | | Date | Wed, 6 May 2026 12:06:33 -0400 | | From | Pasha Tatashin <> | | Subject | Re: [PATCH v1 1/3] liveupdate: skip serialization for context-preserving kexec |
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On 05-06 17:33, Pratyush Yadav wrote: > On Wed, May 06 2026, Pasha Tatashin wrote: > > > 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. > > My point is that we keep KHO data in the 1st kernel but do not pass it > to the 2nd kernel via setup_data or the devicetree because it should not > use that memory anyway. So essentially we add a check in > kho_fill_kimage() and return early if preserve_context is set.
This is a good point, I think we should do that to prevent passing via setup_data on preserve_context kexec.
> > I don't think it makes much difference in practice so no strong > opinions. Fine either way. > > [...] > > -- > Regards, > Pratyush Yadav
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