From e86436ad0ad2a9aaf88802d69b68f02cbd1f04a9 Mon Sep 17 00:00:00 2001 From: Ran Xiaokai Date: Thu, 22 Jan 2026 13:27:40 +0000 Subject: [PATCH] kho: init alloc tags when restoring pages from reserved memory 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. Link: https://lkml.kernel.org/r/20260122132740.176468-1-ranxiaokai627@163.com Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation") Signed-off-by: Ran Xiaokai Reviewed-by: Pratyush Yadav Reviewed-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Kent Overstreet Cc: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton --- 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; } -- 2.47.3