Merge "init: Add diagnostics for snapuserd hangs" am: 74d558c170 (2bebf0d0) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/snapuserd/snapuserd_daemon.cpp

+2 −0

Original line number	Diff line number	Diff line
		@@ -209,6 +209,8 @@ void Daemon::SignalHandler(int signal) {
		int main(int argc, char** argv) {
		android::base::InitLogging(argv, &android::base::KernelLogger);

		LOG(INFO) << "snapuserd daemon about to start";

		android::snapshot::Daemon& daemon = android::snapshot::Daemon::Instance();

		if (!daemon.StartDaemon(argc, argv)) {

init/init.cpp

+83 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,7 @@
		#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
		#include <sys/_system_properties.h>

		#include <filesystem>
		#include <functional>
		#include <map>
		#include <memory>
		@@ -46,6 +47,7 @@
		#include <android-base/logging.h>
		#include <android-base/parseint.h>
		#include <android-base/properties.h>
		#include <android-base/scopeguard.h>
		#include <android-base/stringprintf.h>
		#include <android-base/strings.h>
		#include <backtrace/Backtrace.h>
		@@ -773,6 +775,82 @@ static Result<void> ConnectEarlyStageSnapuserdAction(const BuiltinArguments& arg
		return {};
		}

		static bool SystemReadSmokeTest() {
		std::string dev = "/dev/block/mapper/system"s + fs_mgr_get_slot_suffix();
		android::base::unique_fd fd(open(dev.c_str(), O_RDONLY));
		if (fd < 0) {
		PLOG(ERROR) << "open " << dev << " failed, will not diangose snapuserd hangs";
		return false;
		}

		for (size_t i = 1; i <= 100; i++) {
		// Skip around the partition a bit.
		size_t offset = i * 4096 * 512;

		char b;
		ssize_t n = TEMP_FAILURE_RETRY(pread(fd.get(), &b, 1, offset));
		if (n < 0) {
		PLOG(ERROR) << "snapuserd smoke test read failed";
		return false;
		}
		}
		return true;
		}

		static void DiagnoseSnapuserdHang(pid_t pid) {
		bool succeeded = false;

		std::mutex m;
		std::condition_variable cv;

		// Enforce an ordering between this and the thread startup, by taking the
		// lock before we lanuch the thread.
		std::unique_lock<std::mutex> cv_lock(m);

		std::thread t([&]() -> void {
		std::lock_guard<std::mutex> lock(m);
		succeeded = SystemReadSmokeTest();
		cv.notify_all();
		});

		auto join = android::base::make_scope_guard([&]() -> void {
		// If the smoke test is hung, then this will too. We expect the device to
		// automatically reboot once the watchdog kicks in.
		t.join();
		});

		auto now = std::chrono::system_clock::now();
		auto deadline = now + 10s;
		auto status = cv.wait_until(cv_lock, deadline);
		if (status == std::cv_status::timeout) {
		LOG(ERROR) << "snapuserd smoke test timed out";
		} else if (!succeeded) {
		LOG(ERROR) << "snapuserd smoke test failed";
		}

		if (succeeded) {
		LOG(INFO) << "snapuserd smoke test succeeded";
		return;
		}

		while (true) {
		LOG(ERROR) << "snapuserd problem detected, printing open fds";

		std::error_code ec;
		std::string proc_dir = "/proc/" + std::to_string(pid) + "/fd";
		for (const auto& entry : std::filesystem::directory_iterator(proc_dir)) {
		std::string target;
		if (android::base::Readlink(entry.path(), &target)) {
		LOG(ERROR) << "snapuserd opened: " << target;
		} else {
		LOG(ERROR) << "snapuserd opened: " << entry.path();
		}
		}

		std::this_thread::sleep_for(10s);
		}
		}

		int SecondStageMain(int argc, char** argv) {
		if (REBOOT_BOOTLOADER_ON_PANIC) {
		InstallRebootSignalHandlers();
		@@ -786,6 +864,11 @@ int SecondStageMain(int argc, char** argv) {
		InitKernelLogging(argv);
		LOG(INFO) << "init second stage started!";

		if (auto pid = GetSnapuserdFirstStagePid()) {
		std::thread t(DiagnoseSnapuserdHang, *pid);
		t.detach();
		}

		// Update $PATH in the case the second stage init is newer than first stage init, where it is
		// first set.
		if (setenv("PATH", _PATH_DEFPATH, 1) != 0) {