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authorHugh Dickins <hughd@google.com>2023-10-24 09:38:41 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-10-26 02:47:14 +0300
commitb1454b463c217e5bc553acc44b2389d9257c9708 (patch)
treed6fd21b602184f797eb246bce240a4ad23df0690 /mm/mlock.c
parent1cbf0a58847b30507611f92ad69964ef37264d14 (diff)
downloadlinux-b1454b463c217e5bc553acc44b2389d9257c9708.tar.xz
mm: mlock: avoid folio_within_range() on KSM pages
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>
Diffstat (limited to 'mm/mlock.c')
-rw-r--r--mm/mlock.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
index aa44456200e3..086546ac5766 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;