Re: [PATCH] liveupdate: validate session type before performing operation

[Pratyush Yadav <pratyush@kernel.org>]

On Tue, May 26 2026, Mike Rapoport wrote:

> From: Mike Rapoport (Microsoft) <rppt@kernel.org>
>
> On Tue, 19 May 2026 14:24:26 +0200, Pratyush Yadav wrote:
>> The sessions ioctls are not applicable to all session types. PRESERVE_FD
>> is only applicable to outgoing sessions. RETRIEVE_FD and FINISH are only
>> valid for incoming session. Calling a incoming ioctl on an outgoing
>> session is invalid and can cause file handlers to run into unexpected
>> errors.
>> 
>> For example, a user can create a (outgoing) session, preserve a memfd,
>> and then immediately do a retrieve without doing a kexec in between.
>> This would result in memfd's retrieve handler to run. The handlers
>> expects to be called from a post-kexec context, and will try to do a
>> kho_restore_vmalloc() or kho_restore_folio() to try and restore memory.
>> 
>> [...]
>
> Applied to fixes branch of liveupdate/linux.git tree, thanks!

Thanks! I will test the selftest update that Pasha suggested as a follow
up, since that will be content for liveupdate/next.

>
> [1/1] liveupdate: validate session type before performing operation
>       commit: da7f658ccc8da60d836051a7af1c53e643f4bd11
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/liveupdate/linux
> branch: fixes
>
> --
> Sincerely yours,
> Mike.
>

-- 
Regards,
Pratyush Yadav