From: Miaohe Lin linmiaohe@huawei.com
mainline inclusion from mainline-v5.19-rc1 commit: f3b9e8cc8b09ba3b41bb068c24a1061e8a70d26f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9JPDJ
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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We can't assume pte_offset_map_lock will return same orig_pte value. So it's necessary to reacquire the orig_pte or pte_unmap_unlock will unmap the stale pte.
Link: https://lkml.kernel.org/r/20220416081416.23304-1-linmiaohe@huawei.com Fixes: 9c276cc65a58 ("mm: introduce MADV_COLD") Fixes: 854e9ed09ded ("mm: support madvise(MADV_FREE)") Signed-off-by: Miaohe Lin linmiaohe@huawei.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Michal Hocko mhocko@suse.com Cc: Hugh Dickins hughd@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Ma Wupeng mawupeng1@huawei.com --- mm/madvise.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/madvise.c b/mm/madvise.c index 2b344256d4be..926bf4523bef 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -451,12 +451,12 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, if (split_huge_page(page)) { unlock_page(page); put_page(page); - pte_offset_map_lock(mm, pmd, addr, &ptl); + orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); break; } unlock_page(page); put_page(page); - pte = pte_offset_map_lock(mm, pmd, addr, &ptl); + orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); pte--; addr -= PAGE_SIZE; continue; @@ -669,12 +669,12 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, if (split_huge_page(page)) { unlock_page(page); put_page(page); - pte_offset_map_lock(mm, pmd, addr, &ptl); + orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); goto out; } unlock_page(page); put_page(page); - pte = pte_offset_map_lock(mm, pmd, addr, &ptl); + orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl); pte--; addr -= PAGE_SIZE; continue;