android: binder: Fix null ptr dereference in debug msg

Sherry Yang · gregkh · commit ae65c8510f33 · 2017-10-21T10:14:20.000+02:00
Don't access next-&gt;data in kernel debug message when the
next buffer is null.

Acked-by: Arve Hjønnevåg &lt;arve@android.com&gt;
Signed-off-by: Sherry Yang &lt;sherryy@android.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
@@ -560,7 +560,7 @@ static void binder_delete_free_buffer(struct binder_alloc *alloc,
 		binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 				   "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 				   alloc->pid, buffer->data,
-				   prev->data, next->data);
+				   prev->data, next ? next->data : NULL);
 		binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 					 buffer_start_page(buffer) + PAGE_SIZE,
 					 NULL);
