kho: make preserved pages compatible with deferred struct page init

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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, kho_preserved_memory_reserve() 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 the struct page is already
initialized.

Signed-off-by: Evangelos Petrongonas <epetron@amazon.de>
Co-developed-by: Michal Clapinski <mclapinski@google.com>
Signed-off-by: Michal Clapinski <mclapinski@google.com>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Link: https://patch.msgid.link/20260423122538.140993-3-mclapinski@google.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

...

This commit is contained in:

Evangelos Petrongonas 2026-04-23 14:25:37 +02:00 • committed by Mike Rapoport (Microsoft)

parent bf480c6133

commit c6073743d0

2 changed files with 26 additions and 3 deletions

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2

kernel/liveupdate/Kconfig

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27

kernel/liveupdate/kexec_handover.c

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