Reset binder service threads' cgroup/priority after command completion
To prevent buggy command implementations from poisoning binder threads'
scheduling class & priority for future command execution, we now reset the
cgroup and thread priority to foreground/normal when a binder service thread
finishes executing the designated command.
Change-Id: Ibc0ab2485751453f6dc96fdb4eb877fd02796e3f
diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index e04b2bf..b2a7db8 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -426,6 +426,21 @@
result = executeCommand(cmd);
}
+ // After executing the command, ensure that the thread is returned to the
+ // default cgroup and priority before rejoining the pool. This is a failsafe
+ // in case the command implementation failed to properly restore the thread's
+ // scheduling parameters upon completion.
+ int my_id;
+#ifdef HAVE_GETTID
+ my_id = gettid();
+#else
+ my_id = getpid();
+#endif
+ if (!set_sched_policy(my_id, SP_FOREGROUND)) {
+ // success; reset the priority as well
+ setpriority(PRIO_PROCESS, my_id, ANDROID_PRIORITY_NORMAL);
+ }
+
// Let this thread exit the thread pool if it is no longer
// needed and it is not the main process thread.
if(result == TIMED_OUT && !isMain) {
