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

Pasha Tatashin
2026-01-13T16:22:11Z

On Mon, Jan 12, 2026 at 10:34 PM <ranxiaokai627@163.com> wrote:
>
> 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>

Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.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