Re: [PATCH v2] kho: skip KHO for crash kernel

Pratyush Yadav
2026-04-16T16:40:50Z

On Thu, Apr 16 2026, Evangelos Petrongonas wrote:

> On Mon, Apr 13, 2026 at 01:52:40PM +0000 Pratyush Yadav wrote:
>> Hi Evangelos,
>>
>> On Fri, Apr 10 2026, Evangelos Petrongonas wrote:
[...]
>> > Note regarding backporting
>> > The offending commit was deployed with 6.19. The only other supported
>> > kernel version with 6.18, unless I miss someting uses
>> > ```
>> > if (!kho_out.finalized)
>> > ```
>> > which in the case of crash kernel it shouldn't be finalised.
>>
>> While normally you should load the crash kernel early in boot and at
>> that point KHO should not be finalized, I don't see anything that
>> prevents crash kernel from being loaded after finalize. In which case,
>> you can trigger this bug before d7255959b69a ("kho: allow kexec load
>> before KHO finalization") as well. Also, before f322a97aeb2a ("kho: only
>> fill kimage if KHO is finalized") (landed in v6.18) kho_fill_kimage()
>> was also guarded by if (!kho_enable). So you'd hit this bug in all
>> kernels before that point in the very same way as today.
>>
>> So should we update Fixes to 3bdecc3c93f9 ("kexec: add KHO support to
>> kexec file loads") and Cc stable?
>>
> But in this case it seems a userspace misuse if it finalizes kho for
> crash kernel. Whereas with the current state we hit the bug with a sane
> userspace. Yeap we would hit that in earlier kernel than 6.18, but none
> with KHO is supported is it?
>
> I don't have strong objection for backporting it to 6.18, but it feels
> unnecessary.

Fair enough. Let's leave it as it is then.

[...]

--
Regards,
Pratyush Yadav