kho: mm: don't allow deferred struct page with KHO

KHO uses struct pages for the preserved memory early in boot, however,
with deferred struct page initialization, only a small portion of memory
has properly initialized struct pages.

This problem was detected where vmemmap is poisoned, and illegal flag
combinations are detected.

Don't allow them to be enabled together, and later we will have to teach
KHO to work properly with deferred struct page init kernel feature.

Link: https://lkml.kernel.org/r/20250808201804.772010-3-pasha.tatashin@soleen.com
Fixes: 4e1d010e3bda ("kexec: add config option for KHO")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Coiby Xu <coxu@redhat.com>
Cc: Dave Vasilevsky <dave@vasilevsky.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 2ee603a98813e22f015b1c2b99ba793adcfbca93..1224dd937df0c4438fd73f4d95a16d53239e5dfe 100644 (file)
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -97,6 +97,7 @@ config KEXEC_JUMP
 config KEXEC_HANDOVER
        bool "kexec handover"
        depends on ARCH_SUPPORTS_KEXEC_HANDOVER && ARCH_SUPPORTS_KEXEC_FILE
+       depends on !DEFERRED_STRUCT_PAGE_INIT
        select MEMBLOCK_KHO_SCRATCH
        select KEXEC_FILE
        select DEBUG_FS