The patch titled
Subject: mm/swapfile: skip HugeTLB pages for unuse_vma
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-swapfile-skip-hugetlb-pages-for-unuse_vma.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swapfile-skip-hugetlb-pages-for-unuse_vma.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: mm/swapfile: skip HugeTLB pages for unuse_vma
Date: Tue, 15 Oct 2024 09:45:21 +0800
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>
---
mm/swapfile.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/swapfile.c~mm-swapfile-skip-hugetlb-pages-for-unuse_vma
+++ a/mm/swapfile.c
@@ -2313,7 +2313,7 @@ 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;
_
Patches currently in -mm which might be from liushixin2@xxxxxxxxxx are
mm-swapfile-skip-hugetlb-pages-for-unuse_vma.patch
