[PATCH v2] kho: init alloc tags when restoring pages from reserved memory

ranxiaokai627
2026-01-13T03:35:31Z

From: Ran Xiaokai <ran.xiaokai@zte.com.cn>

Memblock pages (including reserved memory) should have their allocation
tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
released to the page allocator. When kho restores pages through
kho_restore_page(), missing this call causes mismatched
allocation/deallocation tracking and below warning message:
alloc_tag was not set
WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1: swapper/0/1
RIP: 0010:___free_pages+0xb8/0x260
kho_restore_vmalloc+0x187/0x2e0
kho_test_init+0x3c4/0xa30
do_one_initcall+0x62/0x2b0
kernel_init_freeable+0x25b/0x480
kernel_init+0x1a/0x1c0
ret_from_fork+0x2d1/0x360

Add missing clear_page_tag_ref() annotation in kho_restore_page() to
fix this.

Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
---
kernel/liveupdate/kexec_handover.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index cd6b3fb9dcae..2d47f2c50bd8 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -268,6 +268,7 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio)
else
kho_init_pages(page, nr_pages);

+ clear_page_tag_ref(page);
adjust_managed_page_count(page, nr_pages);
return page;
}
--
2.25.1