From: Thomas Hellstrom <[email protected]> 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]> --- 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
