1 files changed, 6 insertions, 0 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 56a0da1f9979..d991063ce75e 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1270,6 +1270,12 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 		slot = list_entry(slot->mm_list.next, struct mm_slot, mm_list);
 		ksm_scan.mm_slot = slot;
 		spin_unlock(&ksm_mmlist_lock);
+		/*
+		 * Although we tested list_empty() above, a racing __ksm_exit
+		 * of the last mm on the list may have removed it since then.
+		 */
+		if (slot == &ksm_mm_head)
+			return NULL;
 next_mm:
 		ksm_scan.address = 0;
 		ksm_scan.rmap_list = &slot->rmap_list;