According to documentation on barriers, stores issued before a LOCK can
complete after the lock implying that it's possible tlb_flush_pending can
be visible after a page table update. As per revised documentation, this patch
adds a smp_mb__before_spinlock to guarantee the correct ordering.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
include/linux/mm_types.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c122bb1..a12f2ab 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -482,7 +482,12 @@ static inline bool tlb_flush_pending(struct mm_struct *mm)
static inline void set_tlb_flush_pending(struct mm_struct *mm)
{
mm->tlb_flush_pending = true;
- barrier();
+
+ /*
+ * Guarantee that the tlb_flush_pending store does not leak into the
+ * critical section updating the page tables
+ */
+ smp_mb__before_spinlock();
}
/* Clearing is done after a TLB flush, which also provides a barrier. */
static inline void clear_tlb_flush_pending(struct mm_struct *mm)
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>