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Subject[PATCH 4/4] thp: fix MADV_DONTNEED vs clear soft dirty race
Date
Yet another instance of the same race.

Fix is identical to change_huge_pmd().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
fs/proc/task_mmu.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ee3efb229ef6..0ce5294abc2c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -899,7 +899,14 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
- pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
+ pmd_t pmd = *pmdp;
+
+ /* See comment in change_huge_pmd() */
+ pmdp_invalidate(vma, addr, pmdp);
+ if (pmd_dirty(*pmdp))
+ pmd = pmd_mkdirty(pmd);
+ if (pmd_young(*pmdp))
+ pmd = pmd_mkyoung(pmd);

pmd = pmd_wrprotect(pmd);
pmd = pmd_clear_soft_dirty(pmd);
--
2.11.0
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