Merge "Fix thread unwind in CallStack." am: 16909c5fc7 am: 4cea1cd5ce am: 05009ec97a am: 34194c8de6 (63fa82da) · Commits · e / os / android_system_core

libutils/Android.bp

+12 −5

Original line number	Original line	Diff line number	Diff line
	@@ -299,6 +299,7 @@ cc_test {

	srcs: [		srcs: [
	"BitSet_test.cpp",		"BitSet_test.cpp",
			"CallStack_test.cpp",
	"Errors_test.cpp",		"Errors_test.cpp",
	"FileMap_test.cpp",		"FileMap_test.cpp",
	"LruCache_test.cpp",		"LruCache_test.cpp",
	@@ -319,11 +320,14 @@ cc_test {
	"SystemClock_test.cpp",		"SystemClock_test.cpp",
	],		],
	shared_libs: [		shared_libs: [
	"libz",		"libbase",
	"liblog",
	"libcutils",		"libcutils",
			"liblog",
			"liblzma",
			"libunwindstack",
	"libutils",		"libutils",
	"libbase",		"libutilscallstack",
			"libz",
	],		],
	},		},
	linux: {		linux: {
	@@ -334,9 +338,12 @@ cc_test {
	},		},
	host: {		host: {
	static_libs: [		static_libs: [
	"libutils",
	"liblog",
	"libbase",		"libbase",
			"liblog",
			"liblzma",
			"libunwindstack_no_dex",
			"libutils",
			"libutilscallstack",
	],		],
	},		},
	},		},

libutils/CallStack.cpp

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -49,7 +49,7 @@ void CallStack::update(int32_t ignoreDepth, pid_t tid) {
	unwindstack::AndroidUnwinderData data;		unwindstack::AndroidUnwinderData data;
	std::optional<pid_t> tid_val;		std::optional<pid_t> tid_val;
	if (tid != -1) {		if (tid != -1) {
	*tid_val = tid;		tid_val = tid;
	}		}
	if (!unwinder.Unwind(tid_val, data)) {		if (!unwinder.Unwind(tid_val, data)) {
	ALOGW("%s: Failed to unwind callstack: %s", __FUNCTION__, data.GetErrorString().c_str());		ALOGW("%s: Failed to unwind callstack: %s", __FUNCTION__, data.GetErrorString().c_str());

libutils/CallStack_test.cpp

0 → 100644

+62 −0

Original line number	Original line	Diff line number	Diff line
			/*
			* Copyright (C) 2022 The Android Open Source Project
			*
			* Licensed under the Apache License, Version 2.0 (the "License");
			* you may not use this file except in compliance with the License.
			* You may obtain a copy of the License at
			*
			* http://www.apache.org/licenses/LICENSE-2.0
			*
			* Unless required by applicable law or agreed to in writing, software
			* distributed under the License is distributed on an "AS IS" BASIS,
			* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
			* See the License for the specific language governing permissions and
			* limitations under the License.
			*/

			#include <unistd.h>

			#include <thread>

			#include <android-base/threads.h>
			#include <gtest/gtest.h>
			#include <utils/CallStack.h>

			[[clang::noinline]] extern "C" void CurrentCaller(android::String8& backtrace) {
			android::CallStack cs;
			cs.update();
			backtrace = cs.toString();
			}

			TEST(CallStackTest, current_backtrace) {
			android::String8 backtrace;
			CurrentCaller(backtrace);

			ASSERT_NE(-1, backtrace.find("(CurrentCaller")) << "Full backtrace:\n" << backtrace;
			}

			[[clang::noinline]] extern "C" void ThreadBusyWait(std::atomic<pid_t>* tid, volatile bool* done) {
			*tid = android::base::GetThreadId();
			while (!*done) {
			}
			}

			TEST(CallStackTest, thread_backtrace) {
			// Use a volatile to avoid any problems unwinding since sometimes
			// accessing a std::atomic does not include unwind data at every
			// instruction and leads to failed unwinds.
			volatile bool done = false;
			std::atomic<pid_t> tid = -1;
			std::thread thread([&tid, &done]() { ThreadBusyWait(&tid, &done); });

			while (tid == -1) {
			}

			android::CallStack cs;
			cs.update(0, tid);

			done = true;
			thread.join();

			ASSERT_NE(-1, cs.toString().find("(ThreadBusyWait")) << "Full backtrace:\n" << cs.toString();
			}