Re: [RFC PATCH 0/2] memblock: keep reserve_mem regions out of KHO bootmem

[Jose A. Perez de Azpillaga]

On 11/4/26 1:19 PM, Pratyush Yadav wrote:
> On Wed, Nov 04 2026, Jose A. Perez de Azpillaga wrote:
> 
>> On 10/22/26 10:16 PM, Jose A. Perez de Azpillaga wrote:
>>> On 10/22/26 3:37 PM, Pratyush Yadav wrote:
>>>> On Wed, Oct 21 2026, Jose A. Perez de Azpillaga wrote:
>>>>
>>>>> On a KHO boot, a reserve_mem= region that can't be revived (new name,
>>>>> size or alignment) can be allocated from KHO bootmem, which the next
>>>>> kernel boots out of. With CONFIG_KEXEC_HANDOVER_DEBUG preserving it
>>>>> fails; without it, the next kernel's memmap ends up on top of it.
>>>> What's your use-case? Why are you adding new reserve_mem regions after
>>>> cold boot? I'd rather avoid making purely theoretical fixes.
>>>
>>> I don't have one, I found it through the TODO. a different reserve_mem=
>>> in the cmdline passed to kexec is enough to hit it.
> 
> If there was a use case, I wouldn't mind fixing it. But I'd rather not
> add code we don't have a use case for.
> 
>>>
>>> if it isn't meant to work across a live update, would you rather have
>>> reserve_mem() fail on KHO boot when it can't revive the region?
> 
> This sounds good I think.
> 

okay, I'll drop 1/2 and send that as v2 :)

-- 
cheers,
jose a. p-a