The quilt patch titled
Subject: mm/damon: validate if the pmd entry is present before accessing
has been removed from the -mm tree. Its filename was
mm-damon-validate-if-the-pmd-entry-is-present-before-accessing.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: mm/damon: validate if the pmd entry is present before accessing
Date: Wed, 17 Aug 2022 14:21:12 +0800
The pmd_huge() is used to validate if the pmd entry is mapped by a huge
page, also including the case of non-present (migration or hwpoisoned) pmd
entry on arm64 or x86 architectures. Thus we should validate if it is
present before making the pmd entry old or getting young state, otherwise
we can not get the correct corresponding page.
Link: https://lkml.kernel.org/r/2838b6737bc259cf575ff11fd1c4b7fdb340fa73.1660717122.git.baolin.wang@xxxxxxxxxxxxxxxxx
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/vaddr.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/mm/damon/vaddr.c~mm-damon-validate-if-the-pmd-entry-is-present-before-accessing
+++ a/mm/damon/vaddr.c
@@ -304,6 +304,11 @@ static int damon_mkold_pmd_entry(pmd_t *
if (pmd_huge(*pmd)) {
ptl = pmd_lock(walk->mm, pmd);
+ if (!pmd_present(*pmd)) {
+ spin_unlock(ptl);
+ return 0;
+ }
+
if (pmd_huge(*pmd)) {
damon_pmdp_mkold(pmd, walk->mm, addr);
spin_unlock(ptl);
@@ -431,6 +436,11 @@ static int damon_young_pmd_entry(pmd_t *
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (pmd_huge(*pmd)) {
ptl = pmd_lock(walk->mm, pmd);
+ if (!pmd_present(*pmd)) {
+ spin_unlock(ptl);
+ return 0;
+ }
+
if (!pmd_huge(*pmd)) {
spin_unlock(ptl);
goto regular_page;
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-migrate-do-not-retry-10-times-for-the-subpages-of-fail-to-migrate-thp.patch
mm-damon-replace-pmd_huge-with-pmd_trans_huge-for-thp.patch
