On Thu, Mar 21, 2024 at 02:24:43PM +0000, Matthew Wilcox (Oracle) wrote: > The current folio_test_hugetlb() can be fooled by a concurrent folio split > into returning true for a folio which has never belonged to hugetlbfs. > This can't happen if the caller holds a refcount on it, but we have a > few places (memory-failure, compaction, procfs) which do not and should > not take a speculative reference. > > Since hugetlb pages do not use individual page mapcounts (they are always > fully mapped and use the entire_mapcount field to record the number > of mappings), the PageType field is available now that page_mapcount() > ignores the value in this field. Update vmcoreinfo: diff --git a/kernel/vmcore_info.c b/kernel/vmcore_info.c index f95516cd45bb..41372f5d5c19 100644 --- a/kernel/vmcore_info.c +++ b/kernel/vmcore_info.c @@ -205,11 +205,10 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_NUMBER(PG_head_mask); #define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy) VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE); -#ifdef CONFIG_HUGETLB_PAGE - VMCOREINFO_NUMBER(PG_hugetlb); +#define PAGE_HUGETLB_MAPCOUNT_VALUE( (~PG_hugetlb) + VMCOREINFO_NUMBER(PAGE_HUGETLB_MAPCOUNT_VALUE); #define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline) VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE); -#endif #ifdef CONFIG_KALLSYMS VMCOREINFO_SYMBOL(kallsyms_names);
