6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liu Shixin <liushixin2@xxxxxxxxxx> commit 7528c4fb1237512ee18049f852f014eba80bbe8d upstream. I got a bad pud error and lost a 1GB HugeTLB when calling swapoff. The problem can be reproduced by the following steps: 1. Allocate an anonymous 1GB HugeTLB and some other anonymous memory. 2. Swapout the above anonymous memory. 3. run swapoff and we will get a bad pud error in kernel message: mm/pgtable-generic.c:42: bad pud 00000000743d215d(84000001400000e7) We can tell that pud_clear_bad is called by pud_none_or_clear_bad in unuse_pud_range() by ftrace. And therefore the HugeTLB pages will never be freed because we lost it from page table. We can skip HugeTLB pages for unuse_vma to fix it. Link: https://lkml.kernel.org/r/20241015014521.570237-1-liushixin2@xxxxxxxxxx Fixes: 0fe6e20b9c4c ("hugetlb, rmap: add reverse mapping for hugepage") Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx> Acked-by: Muchun Song <muchun.song@xxxxxxxxx> Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2003,7 +2003,7 @@ static int unuse_mm(struct mm_struct *mm mmap_read_lock(mm); for_each_vma(vmi, vma) { - if (vma->anon_vma) { + if (vma->anon_vma && !is_vm_hugetlb_page(vma)) { ret = unuse_vma(vma, type); if (ret) break;
