Enable fdtrack in system_server.
Spawn a thread that monitors the current fd count, and enables fdtrack
to hunt down leaks when it gets too high.
Bug: http://b/140703823
Test: setprop persist.sys.debug.fdtrack_enable_threshold; stop; start; logcat -c; killall -39 system_server; logcat -d | grep fdtrack
Change-Id: If5831f57d47e6958112abced181f07e18e6a7261
diff --git a/services/core/jni/com_android_server_SystemServer.cpp b/services/core/jni/com_android_server_SystemServer.cpp
index 78b64ca..67254b8 100644
--- a/services/core/jni/com_android_server_SystemServer.cpp
+++ b/services/core/jni/com_android_server_SystemServer.cpp
@@ -14,6 +14,12 @@
* limitations under the License.
*/
+#include <dlfcn.h>
+#include <pthread.h>
+
+#include <chrono>
+#include <thread>
+
#include <jni.h>
#include <nativehelper/JNIHelp.h>
@@ -25,12 +31,17 @@
#include <sensorservicehidl/SensorManager.h>
#include <bionic/malloc.h>
+#include <bionic/reserved_signals.h>
+#include <android-base/properties.h>
#include <cutils/properties.h>
#include <utils/Log.h>
#include <utils/misc.h>
#include <utils/AndroidThreads.h>
+using android::base::GetIntProperty;
+using namespace std::chrono_literals;
+
namespace android {
static void android_server_SystemServer_startSensorService(JNIEnv* /* env */, jobject /* clazz */) {
@@ -68,7 +79,50 @@
static void android_server_SystemServer_initZygoteChildHeapProfiling(JNIEnv* /* env */,
jobject /* clazz */) {
- android_mallopt(M_INIT_ZYGOTE_CHILD_PROFILING, nullptr, 0);
+ android_mallopt(M_INIT_ZYGOTE_CHILD_PROFILING, nullptr, 0);
+}
+
+static int get_current_max_fd() {
+ // Not actually guaranteed to be the max, but close enough for our purposes.
+ int fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+ LOG_ALWAYS_FATAL_IF(fd == -1, "failed to open /dev/null: %s", strerror(errno));
+ close(fd);
+ return fd;
+}
+
+static const char kFdLeakEnableThresholdProperty[] = "persist.sys.debug.fdtrack_enable_threshold";
+static const char kFdLeakAbortThresholdProperty[] = "persist.sys.debug.fdtrack_abort_threshold";
+static const char kFdLeakCheckIntervalProperty[] = "persist.sys.debug.fdtrack_interval";
+
+static void android_server_SystemServer_spawnFdLeakCheckThread(JNIEnv*, jobject) {
+ std::thread([]() {
+ pthread_setname_np(pthread_self(), "FdLeakCheckThread");
+ bool loaded = false;
+ while (true) {
+ const int enable_threshold = GetIntProperty(kFdLeakEnableThresholdProperty, 1024);
+ const int abort_threshold = GetIntProperty(kFdLeakAbortThresholdProperty, 2048);
+ const int check_interval = GetIntProperty(kFdLeakCheckIntervalProperty, 120);
+ int max_fd = get_current_max_fd();
+ if (max_fd > enable_threshold && !loaded) {
+ loaded = true;
+ ALOGE("fd count above threshold of %d, starting fd backtraces", enable_threshold);
+ if (dlopen("libfdtrack.so", RTLD_GLOBAL) == nullptr) {
+ ALOGE("failed to load libfdtrack.so: %s", dlerror());
+ }
+ } else if (max_fd > abort_threshold) {
+ raise(BIONIC_SIGNAL_FDTRACK);
+
+ // Wait for a bit to allow fdtrack to dump backtraces to logcat.
+ std::this_thread::sleep_for(5s);
+
+ LOG_ALWAYS_FATAL(
+ "b/140703823: aborting due to fd leak: check logs for fd "
+ "backtraces");
+ }
+
+ std::this_thread::sleep_for(std::chrono::seconds(check_interval));
+ }
+ }).detach();
}
/*
@@ -80,6 +134,9 @@
{ "startHidlServices", "()V", (void*) android_server_SystemServer_startHidlServices },
{ "initZygoteChildHeapProfiling", "()V",
(void*) android_server_SystemServer_initZygoteChildHeapProfiling },
+ { "spawnFdLeakCheckThread", "()V",
+ (void*) android_server_SystemServer_spawnFdLeakCheckThread },
+
};
int register_android_server_SystemServer(JNIEnv* env)
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index c566341..b93365a 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -353,6 +353,12 @@
*/
private static native void initZygoteChildHeapProfiling();
+
+ /**
+ * Spawn a thread that monitors for fd leaks.
+ */
+ private static native void spawnFdLeakCheckThread();
+
/**
* The main entry point from zygote.
*/
@@ -484,6 +490,11 @@
initZygoteChildHeapProfiling();
}
+ // Debug builds - spawn a thread to monitor for fd leaks.
+ if (Build.IS_DEBUGGABLE) {
+ spawnFdLeakCheckThread();
+ }
+
// Check whether we failed to shut down last time we tried.
// This call may not return.
performPendingShutdown();
