android: binder: Fix null ptr dereference in debug msg

Don't access next->data in kernel debug message when the
next buffer is null.

Acked-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Sherry Yang <sherryy@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index e12072b1d507e8636afa5dffe9811d4471ac0b5c..c2819a3d58a66e63e49cd7e91d3b7caa7a6551a1 100644 (file)
--- 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);