1 files changed, 12 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 79d541f1502b..4f6e566d52fa 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1491,7 +1491,18 @@ static unsigned long __mmap_region(struct file *file, unsigned long addr,
 				vm_flags = vma->vm_flags;
 				goto file_expanded;
 			}
-			vma_iter_config(&vmi, addr, end);
+
+			/*
+			 * In the unlikely even that more memory was needed, but
+			 * not available for the vma merge, the vma iterator
+			 * will have no memory reserved for the write we told
+			 * the driver was happening.  To keep up the ruse,
+			 * ensure the allocation for the store succeeds.
+			 */
+			if (vmg_nomem(&vmg)) {
+				mas_preallocate(&vmi.mas, vma,
+						GFP_KERNEL|__GFP_NOFAIL);
+			}
 		}
 
 		vm_flags = vma->vm_flags;