On Thu, Jan 22, 2026 at 01:27:40PM +0000, [email protected] wrote: > From: Ran Xiaokai <[email protected]> > > 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") > Cc: <[email protected]> > Signed-off-by: Ran Xiaokai <[email protected]>
Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> > --- > > v2 -> v3: > - also call clear_page_tag_ref() for non-compound order-0 tail pages > > kernel/liveupdate/kexec_handover.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/kernel/liveupdate/kexec_handover.c > b/kernel/liveupdate/kexec_handover.c > index d4482b6e3cae..96767b106cac 100644 > --- a/kernel/liveupdate/kexec_handover.c > +++ b/kernel/liveupdate/kexec_handover.c > @@ -255,6 +255,14 @@ static struct page *kho_restore_page(phys_addr_t phys, > bool is_folio) > if (is_folio && info.order) > prep_compound_page(page, info.order); > > + /* Always mark headpage's codetag as empty to avoid accounting mismatch > */ > + clear_page_tag_ref(page); > + if (!is_folio) { > + /* Also do that for the non-compound tail pages */ > + for (unsigned int i = 1; i < nr_pages; i++) > + clear_page_tag_ref(page + i); > + } > + > adjust_managed_page_count(page, nr_pages); > return page; > } > -- > 2.25.1 > > -- Sincerely yours, Mike.
