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authorThomas Hellstrom <[email protected]>2019-10-04 11:04:43 +0200
committerThomas Hellstrom <[email protected]>2019-11-06 13:02:25 +0100
commitace88f1018b88167a78bafd545d30816d6e207bf (patch)
tree52d80c8bd41e9dd0efea092bd4eeb96915f7536d
parentea81bae46032022656d45d4a395f1bf3b96697f0 (diff)
mm: pagewalk: Take the pagetable lock in walk_pte_range()
Without the lock, anybody modifying a pte from within this function might have it concurrently modified by someone else. Cc: Matthew Wilcox <[email protected]> Cc: Will Deacon <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Huang Ying <[email protected]> Cc: Jérôme Glisse <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Thomas Hellstrom <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]>
-rw-r--r--mm/pagewalk.c5
1 files 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;
}