1 files changed, 32 insertions, 12 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index d58763b6b009..f2081934eb8b 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -822,6 +822,7 @@ static void
 binder_enqueue_deferred_thread_work_ilocked(struct binder_thread *thread,
 					    struct binder_work *work)
 {
+	WARN_ON(!list_empty(&thread->waiting_thread_node));
 	binder_enqueue_work_ilocked(work, &thread->todo);
 }
 
@@ -839,6 +840,7 @@ static void
 binder_enqueue_thread_work_ilocked(struct binder_thread *thread,
 				   struct binder_work *work)
 {
+	WARN_ON(!list_empty(&thread->waiting_thread_node));
 	binder_enqueue_work_ilocked(work, &thread->todo);
 	thread->process_todo = true;
 }
@@ -1270,19 +1272,12 @@ static int binder_inc_node_nilocked(struct binder_node *node, int strong,
 		} else
 			node->local_strong_refs++;
 		if (!node->has_strong_ref && target_list) {
+			struct binder_thread *thread = container_of(target_list,
+						    struct binder_thread, todo);
 			binder_dequeue_work_ilocked(&node->work);
-			/*
-			 * Note: this function is the only place where we queue
-			 * directly to a thread->todo without using the
-			 * corresponding binder_enqueue_thread_work() helper
-			 * functions; in this case it's ok to not set the
-			 * process_todo flag, since we know this node work will
-			 * always be followed by other work that starts queue
-			 * processing: in case of synchronous transactions, a
-			 * BR_REPLY or BR_ERROR; in case of oneway
-			 * transactions, a BR_TRANSACTION_COMPLETE.
-			 */
-			binder_enqueue_work_ilocked(&node->work, target_list);
+			BUG_ON(&thread->todo != target_list);
+			binder_enqueue_deferred_thread_work_ilocked(thread,
+								   &node->work);
 		}
 	} else {
 		if (!internal)
@@ -2723,6 +2718,7 @@ static void binder_transaction(struct binder_proc *proc,
 {
 	int ret;
 	struct binder_transaction *t;
+	struct binder_work *w;
 	struct binder_work *tcomplete;
 	binder_size_t *offp, *off_end, *off_start;
 	binder_size_t off_min;
@@ -2864,6 +2860,29 @@ static void binder_transaction(struct binder_proc *proc,
 			goto err_invalid_target_handle;
 		}
 		binder_inner_proc_lock(proc);
+
+		w = list_first_entry_or_null(&thread->todo,
+					     struct binder_work, entry);
+		if (!(tr->flags & TF_ONE_WAY) && w &&
+		    w->type == BINDER_WORK_TRANSACTION) {
+			/*
+			 * Do not allow new outgoing transaction from a
+			 * thread that has a transaction at the head of
+			 * its todo list. Only need to check the head
+			 * because binder_select_thread_ilocked picks a
+			 * thread from proc->waiting_threads to enqueue
+			 * the transaction, and nothing is queued to the
+			 * todo list while the thread is on waiting_threads.
+			 */
+			binder_user_error("%d:%d new transaction not allowed when there is a transaction on thread todo\n",
+					  proc->pid, thread->pid);
+			binder_inner_proc_unlock(proc);
+			return_error = BR_FAILED_REPLY;
+			return_error_param = -EPROTO;
+			return_error_line = __LINE__;
+			goto err_bad_todo_list;
+		}
+
 		if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
 			struct binder_transaction *tmp;
 
@@ -3247,6 +3266,7 @@ err_alloc_tcomplete_failed:
 	kfree(t);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION);
 err_alloc_t_failed:
+err_bad_todo_list:
 err_bad_call_stack:
 err_empty_call_stack:
 err_dead_binder: