linux-kernel - Re: [PATCH v2] kho: add support for deferred struct page init

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Message-ID: <2vxzecmssnxx.fsf@kernel.org>
Date: Tue, 10 Feb 2026 14:55:22 +0100
From: Pratyush Yadav <pratyush@...nel.org>
To: Michal Clapinski <mclapinski@...gle.com>
Cc: Evangelos Petrongonas <epetron@...zon.de>,  Pasha Tatashin
 <pasha.tatashin@...een.com>,  Mike Rapoport <rppt@...nel.org>,  Pratyush
 Yadav <pratyush@...nel.org>,  Alexander Graf <graf@...zon.com>,
  kexec@...ts.infradead.org,  linux-mm@...ck.org,
  linux-kernel@...r.kernel.org,  Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2] kho: add support for deferred struct page init

On Tue, Feb 10 2026, Michal Clapinski wrote:

> When `CONFIG_DEFERRED_STRUCT_PAGE_INIT` is enabled, struct page
> initialization is deferred to parallel kthreads that run later
> in the boot process.
>
> During KHO restoration, `deserialize_bitmap()` writes metadata for
> each preserved memory region. However, if the struct page has not been
> initialized, this write targets uninitialized memory, potentially
> leading to errors like:
> ```
> BUG: unable to handle page fault for address: ...
> ```
>
> Fix this by introducing `kho_get_preserved_page()`,  which ensures
> all struct pages in a preserved region are initialized by calling
> `init_deferred_page()` which is a no-op when deferred init is disabled
> or when the struct page is already initialized.
>
> Signed-off-by: Evangelos Petrongonas <epetron@...zon.de>
> Signed-off-by: Michal Clapinski <mclapinski@...gle.com>

Reviewed-by: Pratyush Yadav (Google) <pratyush@...nel.org>

[...]

-- 
Regards,
Pratyush Yadav