From: Hugh Dickins hughd@google.com
mainline inclusion from mainline-v6.7-rc1 commit b1454b463c217e5bc553acc44b2389d9257c9708 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8YQMW
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Since commit dc68badcede4 ("mm: mlock: update mlock_pte_range to handle large folio") I've just occasionally seen VM_WARN_ON_FOLIO(folio_test_ksm) warnings from folio_within_range(), in a splurge after testing with KSM hyperactive.
folio_referenced_one()'s use of folio_within_vma() is safe because it checks folio_test_large() first; but allow_mlock_munlock() needs to do the same to avoid those warnings (or check !folio_test_ksm() itself? Or move either check into folio_within_range()? Hard to tell without more examples of its use).
Link: https://lkml.kernel.org/r/23852f6a-5bfa-1ffd-30db-30c5560ad426@google.com Fixes: dc68badcede4 ("mm: mlock: update mlock_pte_range to handle large folio") Signed-off-by: Hugh Dickins hughd@google.com Reviewed-by: Yin Fengwei fengwei.yin@intel.com Cc: Lorenzo Stoakes lstoakes@gmail.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Stefan Roesch shr@devkernel.io Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- mm/mlock.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/mm/mlock.c b/mm/mlock.c index 42b6865f8f82..f79d8262c1a0 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -346,6 +346,10 @@ static inline bool allow_mlock_munlock(struct folio *folio, if (!(vma->vm_flags & VM_LOCKED)) return true;
+ /* folio_within_range() cannot take KSM, but any small folio is OK */ + if (!folio_test_large(folio)) + return true; + /* folio not in range [start, end), skip mlock */ if (!folio_within_range(folio, vma, start, end)) return false;