From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Without the lock, anybody modifying a pte from within this function might
have it concurrently modified by someone else.
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
---
mm/pagewalk.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index d48c2a986ea3..c5fa42cab14f 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -10,8 +10,9 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
pte_t *pte;
int err = 0;
const struct mm_walk_ops *ops = walk->ops;
+ spinlock_t *ptl;
- pte = pte_offset_map(pmd, addr);
+ pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
for (;;) {
err = ops->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
if (err)
@@ -22,7 +23,7 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
pte++;
}
- pte_unmap(pte);
+ pte_unmap_unlock(pte, ptl);
return err;
}
--
2.21.0
