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Revert "Android: Add helper methods for printing native stack traces"

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This reverts commit dc32cc00e80972223767be339f9318b803f4a2ae.

Reason for revert: Seems to be breaking Chromium FYI, https://www.google.com/url?q=https://ci.chromium.org/p/chromium/builders/luci.chromium.webrtc.fyi/WebRTC%2520Chromium%2520FYI%2520Android%2520Tests%2520%2528dbg%2529%2520%2528K%2520Nexus5%2529/1807&sa=D&source=hangouts&ust=1548149426180000&usg=AFQjCNGh9aBqv2wNE12D8-6rn9-AJR-cNg

Original change's description:
> Android: Add helper methods for printing native stack traces
> 
> This CL adds utility functions to unwind the stack for a given thread on
> Android ARM devices. This works on top of unwind.h and unwinds native
> (C++) stack traces only. Unwinding a thread from another thread is done
> by overriding the signal handler with a custom function and then
> interrupting the specific thread.
> 
> Bug: webrtc:10168
> Change-Id: If5adffd3a6bb57bf502168743e09a7eefc292bf3
> Reviewed-on: https://webrtc-review.googlesource.com/c/118141
> Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
> Reviewed-by: Tommi <tommi@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#26328}

TBR=magjed@webrtc.org,tommi@webrtc.org

Change-Id: I6e01f9226ef60777cb422baeab042bce8944f9ed
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:10168
Reviewed-on: https://webrtc-review.googlesource.com/c/118683
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26336}
This commit is contained in:
Magnus Jedvert
2019-01-21 11:08:29 +00:00
committed by Commit Bot
parent d7bc09705b
commit 700615fb1c
4 changed files with 0 additions and 476 deletions
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16
sdk/android/BUILD.gn
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@ -68,7 +68,6 @@ if (is_android) {
":native_api_codecs",
":native_api_jni",
":native_api_peerconnection",
":native_api_stacktrace",
":native_api_video",
]
}
@ -981,19 +980,6 @@ if (is_android) {
]
}
# API for capturing and printing native stacktraces.
rtc_static_library("native_api_stacktrace") {
visibility = [ "*" ]
sources = [
"native_api/stacktrace/stacktrace.cc",
"native_api/stacktrace/stacktrace.h",
]
deps = [
"../../rtc_base",
]
}
# API for creating C++ wrapper implementations of api/mediastreaminterface.h
# video interfaces from their Java equivalents.
rtc_static_library("native_api_video") {
@ -1526,7 +1512,6 @@ if (is_android) {
"native_unittests/codecs/wrapper_unittest.cc",
"native_unittests/java_types_unittest.cc",
"native_unittests/peerconnection/peer_connection_factory_unittest.cc",
"native_unittests/stacktrace/stacktrace_unittest.cc",
"native_unittests/test_jni_onload.cc",
"native_unittests/video/video_source_unittest.cc",
]
@ -1552,7 +1537,6 @@ if (is_android) {
":native_api_codecs",
":native_api_jni",
":native_api_peerconnection",
":native_api_stacktrace",
":native_api_video",
":opensles_audio_device_module",
":video_jni",

231
sdk/android/native_api/stacktrace/stacktrace.cc
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@ -1,231 +0,0 @@
/*
* Copyright 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "sdk/android/native_api/stacktrace/stacktrace.h"
#include <dlfcn.h>
#include <errno.h>
#include <linux/futex.h>
#include <sys/ptrace.h>
#include <sys/ucontext.h>
#include <syscall.h>
#include <ucontext.h>
#include <unistd.h>
#include <unwind.h>
#include <atomic>
// ptrace.h is polluting the namespace. Clean up to avoid conflicts with rtc.
#if defined(DS)
#undef DS
#endif
#include "rtc_base/critical_section.h"
#include "rtc_base/logging.h"
#include "rtc_base/strings/string_builder.h"
namespace webrtc {
namespace {
// Maximum stack trace depth we allow before aborting.
constexpr size_t kMaxStackSize = 100;
// Signal that will be used to interrupt threads. SIGURG ("Urgent condition on
// socket") is chosen because Android does not set up a specific handler for
// this signal.
constexpr int kSignal = SIGURG;
// Note: This class is only meant for use within this file, and for the
// simplified use case of a single Wait() and a single Signal(), followed by
// discarding the object (never reused).
// This is a replacement of rtc::Event that is async-safe and doesn't use
// pthread api. This is necessary since signal handlers cannot allocate memory
// or use pthread api. This class is ported from Chromium.
class AsyncSafeWaitableEvent {
public:
AsyncSafeWaitableEvent() {
std::atomic_store_explicit(&futex_, 0, std::memory_order_release);
}
~AsyncSafeWaitableEvent() {}
// Returns false in the event of an error and errno is set to indicate the
// cause of the error.
bool Wait() {
// futex() can wake up spuriously if this memory address was previously used
// for a pthread mutex. So, also check the condition.
while (true) {
int res = syscall(SYS_futex, &futex_, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0,
nullptr, nullptr, 0);
if (std::atomic_load_explicit(&futex_, std::memory_order_acquire) != 0)
return true;
if (res != 0)
return false;
}
}
void Signal() {
std::atomic_store_explicit(&futex_, 1, std::memory_order_release);
syscall(SYS_futex, &futex_, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1, nullptr,
nullptr, 0);
}
private:
std::atomic<int> futex_;
};
// Struct to store the arguments to the signal handler.
struct SignalHandlerOutputState {
// This event is signalled when signal handler is done executing.
AsyncSafeWaitableEvent signal_handler_finish_event;
// Running counter of array index below.
size_t stack_size_counter = 0;
// Array storing the stack trace.
uintptr_t addresses[kMaxStackSize];
};
// Global lock to ensure only one thread gets interrupted at a time.
rtc::GlobalLockPod g_signal_handler_lock;
// Argument passed to the ThreadSignalHandler() from the sampling thread to the
// sampled (stopped) thread. This value is set just before sending signal to the
// thread and reset when handler is done.
SignalHandlerOutputState* volatile g_signal_handler_output_state;
// This function is called iteratively for each stack trace element and stores
// the element in the array from |unwind_output_state|.
_Unwind_Reason_Code UnwindBacktrace(struct _Unwind_Context* unwind_context,
void* unwind_output_state) {
SignalHandlerOutputState* const output_state =
static_cast<SignalHandlerOutputState*>(unwind_output_state);
// Avoid overflowing the stack trace array.
if (output_state->stack_size_counter >= kMaxStackSize)
return _URC_END_OF_STACK;
// Store the instruction pointer in the array. Subtract 2 since we want to get
// the call instruction pointer, not the return address which is the
// instruction after.
output_state->addresses[output_state->stack_size_counter] =
_Unwind_GetIP(unwind_context) - 2;
++output_state->stack_size_counter;
return _URC_NO_REASON;
}
// This signal handler is exectued on the interrupted thread.
void SignalHandler(int signum, siginfo_t* info, void* ptr) {
_Unwind_Backtrace(&UnwindBacktrace, g_signal_handler_output_state);
g_signal_handler_output_state->signal_handler_finish_event.Signal();
}
// Temporarily change the signal handler to a function that records a raw stack
// trace and interrupt the given tid. This function will block until the output
// thread stack trace has been stored in |params|. The return value is an error
// string on failure and null on success.
const char* CaptureRawStacktrace(int pid,
int tid,
SignalHandlerOutputState* params) {
// This function is under a global lock since we are changing the signal
// handler and using global state for the output. The lock is to ensure only
// one thread at a time gets captured. The lock also means we need to be very
// careful with what statements we put in this function, and we should even
// avoid logging here.
struct sigaction act;
struct sigaction old_act;
memset(&act, 0, sizeof(act));
act.sa_sigaction = &SignalHandler;
act.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&act.sa_mask);
rtc::GlobalLockScope ls(&g_signal_handler_lock);
g_signal_handler_output_state = params;
if (sigaction(kSignal, &act, &old_act) != 0)
return "Failed to change signal action";
// Interrupt the thread which will execute SignalHandler() on the given
// thread.
if (tgkill(pid, tid, kSignal) != 0)
return "Failed to interrupt thread";
// Wait until the thread is done recording its stack trace.
if (!params->signal_handler_finish_event.Wait())
return "Failed to wait for thread to finish stack trace";
// Restore previous signal handler.
sigaction(kSignal, &old_act, /* old_act= */ nullptr);
return nullptr;
}
} // namespace
std::vector<StackTraceElement> GetStackTrace(int tid) {
// Only a thread itself can unwind its stack, so we will interrupt the given
// tid with a custom signal handler in order to unwind its stack. The stack
// will be recorded to |params| through the use of the global pointer
// |g_signal_handler_param|.
SignalHandlerOutputState params;
const char* error_string = CaptureRawStacktrace(getpid(), tid, &params);
if (error_string != nullptr) {
RTC_LOG(LS_ERROR) << error_string << ". tid: " << tid
<< ". errno: " << errno;
return {};
}
if (params.stack_size_counter >= kMaxStackSize)
RTC_LOG(LS_WARNING) << "Stack trace for thread " << tid << " was truncated";
// Translate addresses into symbolic information using dladdr().
std::vector<StackTraceElement> stack_trace;
for (size_t i = 0; i < params.stack_size_counter; ++i) {
const uintptr_t address = params.addresses[i];
Dl_info dl_info = {};
if (!dladdr(reinterpret_cast<void*>(address), &dl_info)) {
RTC_LOG(LS_WARNING)
<< "Could not translate address to symbolic information for address "
<< address << " at stack depth " << i;
continue;
}
StackTraceElement stack_trace_element;
stack_trace_element.shared_object_path = dl_info.dli_fname;
stack_trace_element.relative_address = static_cast<uint32_t>(
address - reinterpret_cast<uintptr_t>(dl_info.dli_fbase));
stack_trace_element.symbol_name = dl_info.dli_sname;
stack_trace.push_back(stack_trace_element);
}
return stack_trace;
}
std::string StackTraceToString(
const std::vector<StackTraceElement>& stack_trace) {
rtc::StringBuilder string_builder;
for (size_t i = 0; i < stack_trace.size(); ++i) {
const StackTraceElement& stack_trace_element = stack_trace[i];
string_builder.AppendFormat(
"#%02zu pc %08x %s", i,
static_cast<uint32_t>(stack_trace_element.relative_address),
stack_trace_element.shared_object_path);
// The symbol name is only available for unstripped .so files.
if (stack_trace_element.symbol_name != nullptr)
string_builder.AppendFormat(" %s", stack_trace_element.symbol_name);
string_builder.AppendFormat("\n");
}
return string_builder.Release();
}
} // namespace webrtc

42
sdk/android/native_api/stacktrace/stacktrace.h
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@ -1,42 +0,0 @@
/*
* Copyright 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef SDK_ANDROID_NATIVE_API_STACKTRACE_STACKTRACE_H_
#define SDK_ANDROID_NATIVE_API_STACKTRACE_STACKTRACE_H_
#include <string>
#include <vector>
namespace webrtc {
struct StackTraceElement {
// Pathname of shared object (.so file) that contains address.
const char* shared_object_path;
// Execution address relative to the .so base address. This matches the
// addresses you get with "nm", "objdump", and "ndk-stack", as long as the
// code is compiled with position-independent code. Android requires
// position-independent code since Lollipop.
uint32_t relative_address;
// Name of symbol whose definition overlaps the address. This value is null
// when symbol names are stripped.
const char* symbol_name;
};
// Utility to unwind stack for a given thread on Android ARM devices. This works
// on top of unwind.h and unwinds native (C++) stack traces only.
std::vector<StackTraceElement> GetStackTrace(int tid);
// Get a string representation of the stack trace in a format ndk-stack accepts.
std::string StackTraceToString(
const std::vector<StackTraceElement>& stack_trace);
} // namespace webrtc
#endif // SDK_ANDROID_NATIVE_API_STACKTRACE_STACKTRACE_H_

187
sdk/android/native_unittests/stacktrace/stacktrace_unittest.cc
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@ -1,187 +0,0 @@
/*
* Copyright 2019 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "sdk/android/native_api/stacktrace/stacktrace.h"
#include <dlfcn.h>
#include <vector>
#include "absl/memory/memory.h"
#include "rtc_base/criticalsection.h"
#include "rtc_base/event.h"
#include "rtc_base/logging.h"
#include "rtc_base/platform_thread.h"
#include "rtc_base/strings/string_builder.h"
#include "test/gtest.h"
namespace webrtc {
namespace test {
// Returns the execution address relative to the .so base address. This matches
// the addresses we get from GetStacktrace().
uint32_t GetCurrentRelativeExecutionAddress() {
void* pc = __builtin_return_address(0);
Dl_info dl_info = {};
const bool success = dladdr(pc, &dl_info);
EXPECT_TRUE(success);
return static_cast<uint32_t>(reinterpret_cast<uintptr_t>(pc) -
reinterpret_cast<uintptr_t>(dl_info.dli_fbase));
}
// Returns true if any of the stack trace element is inside the specified
// region.
bool StackTraceContainsRange(const std::vector<StackTraceElement>& stack_trace,
uintptr_t pc_low,
uintptr_t pc_high) {
for (const StackTraceElement& stack_trace_element : stack_trace) {
if (pc_low <= stack_trace_element.relative_address &&
pc_high >= stack_trace_element.relative_address) {
return true;
}
}
return false;
}
class DeadlockInterface {
public:
virtual ~DeadlockInterface() {}
// This function should deadlock until Release() is called.
virtual void Deadlock() = 0;
// This function should release the thread stuck in Deadlock().
virtual void Release() = 0;
};
struct ThreadParams {
volatile int tid;
// Signaled when the deadlock region is entered.
rtc::Event deadlock_start_event;
DeadlockInterface* volatile deadlock_impl;
// Defines an address range within the deadlock will occur.
volatile uint32_t deadlock_region_start_address;
volatile uint32_t deadlock_region_end_address;
// Signaled when the deadlock is done.
rtc::Event deadlock_done_event;
};
class RtcEventDeadlock : public DeadlockInterface {
private:
void Deadlock() override { event.Wait(rtc::Event::kForever); }
void Release() override { event.Set(); }
rtc::Event event;
};
class RtcCriticalSectionDeadlock : public DeadlockInterface {
public:
RtcCriticalSectionDeadlock()
: critscope_(absl::make_unique<rtc::CritScope>(&crit_)) {}
private:
void Deadlock() override { rtc::CritScope lock(&crit_); }
void Release() override { critscope_.reset(); }
rtc::CriticalSection crit_;
std::unique_ptr<rtc::CritScope> critscope_;
};
class SpinDeadlock : public DeadlockInterface {
public:
SpinDeadlock() : is_deadlocked_(true) {}
private:
void Deadlock() override {
while (is_deadlocked_) {
}
}
void Release() override { is_deadlocked_ = false; }
std::atomic<bool> is_deadlocked_;
};
class SleepDeadlock : public DeadlockInterface {
private:
void Deadlock() override { sleep(1000000); }
void Release() override {
// The interrupt itself will break free from the sleep.
}
};
// This is the function that is exectued by the thread that will deadlock and
// have its stacktrace captured.
void ThreadFunction(void* void_params) {
ThreadParams* params = static_cast<ThreadParams*>(void_params);
params->tid = gettid();
params->deadlock_region_start_address = GetCurrentRelativeExecutionAddress();
params->deadlock_start_event.Set();
params->deadlock_impl->Deadlock();
params->deadlock_region_end_address = GetCurrentRelativeExecutionAddress();
params->deadlock_done_event.Set();
}
void TestStacktrace(std::unique_ptr<DeadlockInterface> deadlock_impl) {
// Set params that will be sent to other thread.
ThreadParams params;
params.deadlock_impl = deadlock_impl.get();
// Spawn thread.
rtc::PlatformThread thread(&ThreadFunction, &params, "StacktraceTest");
thread.Start();
// Wait until the thread has entered the deadlock region.
params.deadlock_start_event.Wait(rtc::Event::kForever);
// Acquire the stack trace of the thread which should now be deadlocking.
std::vector<StackTraceElement> stack_trace = GetStackTrace(params.tid);
// Release the deadlock so that the thread can continue.
deadlock_impl->Release();
// Wait until the thread has left the deadlock.
params.deadlock_done_event.Wait(rtc::Event::kForever);
// Assert that the stack trace contains the deadlock region.
EXPECT_TRUE(StackTraceContainsRange(stack_trace,
params.deadlock_region_start_address,
params.deadlock_region_end_address))
<< "Deadlock region: ["
<< rtc::ToHex(params.deadlock_region_start_address) << ", "
<< rtc::ToHex(params.deadlock_region_end_address)
<< "] not contained in: " << StackTraceToString(stack_trace);
thread.Stop();
}
TEST(Stacktrace, TestSpinLock) {
TestStacktrace(absl::make_unique<SpinDeadlock>());
}
TEST(Stacktrace, TestSleep) {
TestStacktrace(absl::make_unique<SleepDeadlock>());
}
// Stack traces originating from kernel space does not include user space stack
// traces for ARM 32.
#ifdef WEBRTC_ARCH_ARM64
TEST(Stacktrace, TestRtcEvent) {
TestStacktrace(absl::make_unique<RtcEventDeadlock>());
}
TEST(Stacktrace, TestRtcCriticalSection) {
TestStacktrace(absl::make_unique<RtcCriticalSectionDeadlock>());
}
#endif
} // namespace test
} // namespace webrtc