From b430575cdf339bdd086f2c0bfdc91fcf7689eca2 Mon Sep 17 00:00:00 2001 From: Liu Shixin Date: Thu, 24 Oct 2024 19:53:41 +0800 Subject: [PATCH] mm/swapfile: skip HugeTLB pages for unuse_vma stable inclusion from stable-v6.6.58 commit bed2b9037806c62166a0ef9a559a1e7e3e1275b8 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAXWWM Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bed2b9037806c62166a0ef9a559a1e7e3e1275b8 -------------------------------- 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@huawei.com Fixes: 0fe6e20b9c4c ("hugetlb, rmap: add reverse mapping for hugepage") Signed-off-by: Liu Shixin Acked-by: Muchun Song Cc: Naoya Horiguchi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman Signed-off-by: Liu Shixin --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index cfb768d3ed73..7f39bebaee34 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2190,7 +2190,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type) 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; -- Gitee