iframe-proxy | Sunbelt Computer Software

Repository navigation

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

// Use of this source code is governed by the MIT license that can be

// found in the LICENSE file.

#include "shell/renderer/oom_stack_trace.h"

#include <atomic>

#include <limits>

#include <string>

#include <string_view>

#include "base/logging.h"

#include "base/memory/raw_ptr.h"

#include "base/no_destructor.h"

#include "base/threading/thread_local.h"

#include "electron/mas.h"

#include "gin/per_isolate_data.h"

#include "shell/common/v8_oom_diagnostics.h"

#include "third_party/abseil-cpp/absl/strings/str_format.h"

#include "v8/include/v8-exception.h"

#include "v8/include/v8-internal.h"

#include "v8/include/v8-isolate.h"

#include "v8/include/v8-local-handle.h"

#include "v8/include/v8-primitive.h"

#include "v8/include/v8-statistics.h"

namespace electron {

namespace {

// Forward-declare so OomState can reference it.

size_t NearHeapLimitCallback(void* data,

size_t current_heap_limit,

size_t initial_heap_limit);

struct OomState : public gin::PerIsolateData::DisposeObserver {

raw_ptr<v8::Isolate> isolate;

std::atomic<bool> is_in_oom{false};

// gin::PerIsolateData::DisposeObserver:

void OnBeforeDispose(v8::Isolate* disposing_isolate) override {

if (!is_in_oom.load()) {

disposing_isolate->RemoveNearHeapLimitCallback(NearHeapLimitCallback, 0);

}

isolate = nullptr;

}

void OnDisposed() override {}

};

base::ThreadLocalOwnedPointer<OomState>& GetOomState() {

static base::NoDestructor<base::ThreadLocalOwnedPointer<OomState>> instance;

return *instance;

}

std::string FormatStackTrace(v8::Isolate* isolate,

v8::Local<v8::StackTrace> stack) {

std::string result;

int frame_count = stack->GetFrameCount();

for (int i = 0; i < frame_count; i++) {

v8::Local<v8::StackFrame> frame = stack->GetFrame(isolate, i);

v8::Local<v8::String> function_name = frame->GetFunctionName();

v8::Local<v8::String> script_name = frame->GetScriptName();

int line = frame->GetLineNumber();

int col = frame->GetColumn();

std::string func_str = "(anonymous)";

if (!function_name.IsEmpty()) {

v8::String::Utf8Value utf8(isolate, function_name);

if (*utf8) {

func_str = *utf8;

}

std::string script_str = "<unknown>";

if (!script_name.IsEmpty()) {

v8::String::Utf8Value utf8(isolate, script_name);

if (*utf8) {

script_str = *utf8;

}

absl::StrAppendFormat(&result, " #%d %s (%s:%d:%d)\n", i, func_str,

script_str, line, col);

}

return result;

}

// Runs at the next V8 safe point after the heap limit was hit.

// At a safe point, all frames have deoptimization data available,

// so CurrentStackTrace won't FATAL on optimized frames.

void CaptureStackOnInterrupt(v8::Isolate* isolate, void* data) {

if (!isolate->InContext()) {

return;

}

v8::HeapStatistics stats;

isolate->GetHeapStatistics(&stats);

// CurrentStackTrace allocates StackTraceInfo + StackFrameInfo objects on the

// V8 managed heap. If the 20 MB bump from NearHeapLimitCallback has been

// partially consumed by the time this interrupt fires, these allocations

// could trigger a secondary OOM. Check headroom before proceeding.

// Note: use addition form to avoid unsigned underflow -- in OOM scenarios,

// used_heap_size can transiently exceed heap_size_limit.

constexpr size_t kMinHeadroom = 2 * 1024 * 1024; // 2 MB

if (stats.used_heap_size() + kMinHeadroom > stats.heap_size_limit()) {

LOG(INFO) << "Skipping JS stack capture: insufficient heap headroom";

return;

}

v8::HandleScope handle_scope(isolate);

v8::Local<v8::StackTrace> stack =

v8::StackTrace::CurrentStackTrace(isolate, 10);

if (stack.IsEmpty() || stack->GetFrameCount() == 0) {

return;

}

std::string js_stack = FormatStackTrace(isolate, stack);

if (!js_stack.empty()) {

v8_oom::RecordJsStack(isolate, js_stack);

LOG(ERROR) << "\n<--- JS stacktrace (captured at safe point) --->\n"

<< js_stack;

}

// V8's pointer compression cage limits the heap to kPtrComprCageReservationSize

// (~4 GB). After this callback returns a new limit, V8 clamps it via

// Heap::AllocatorLimitOnMaxOldGenerationSize() to at most that cage size.

// If current_heap_limit is already near the ceiling the bump is effectively

// zero, the interrupt never gets enough headroom to fire, and we never capture

// a stack trace. When that happens we fall back to recording heap info only.

size_t NearHeapLimitCallback(void* data,

size_t current_heap_limit,

size_t initial_heap_limit) {

auto* state = static_cast<OomState*>(data);

v8::Isolate* isolate = state->isolate;

if (state->is_in_oom.exchange(true)) {

return current_heap_limit;

}

v8::HeapStatistics stats;

isolate->GetHeapStatistics(&stats);

std::string heap_info = absl::StrFormat("Heap: used=%.1fMB limit=%.1fMB",

stats.used_heap_size() / 1048576.0,

stats.heap_size_limit() / 1048576.0);

LOG(ERROR) << "\n<--- Near heap limit --->\n" << heap_info;

v8_oom::RecordJsStack(isolate, heap_info + " (stack pending)");

v8_oom::RecordHeapDiagnostics(isolate);

// Request an interrupt to capture the JS stack at the next safe point,

// where optimized frames have deoptimization data available.

// CurrentStackTrace is unsafe to call directly here because V8 may

// FATAL on optimized frames missing deopt info during OOM.

isolate->RequestInterrupt(CaptureStackOnInterrupt, state);

// Remove ourselves and bump the limit to give V8 room to reach a safe

// point where the interrupt can fire and capture the stack trace.

isolate->RemoveNearHeapLimitCallback(NearHeapLimitCallback, 0);

constexpr size_t kHeapBump = 20 * 1024 * 1024;

size_t new_limit = current_heap_limit + kHeapBump;

#ifdef V8_COMPRESS_POINTERS

constexpr size_t kCageLimit = v8::internal::kPtrComprCageReservationSize;

static_assert(kCageLimit == size_t{1} << 32,

"Cage size changed; review heap bump logic");

#else

constexpr size_t kCageLimit = std::numeric_limits<size_t>::max();

#endif

if (current_heap_limit >= kCageLimit - kHeapBump) {

// The bump will be clamped by V8 to the cage ceiling, leaving no

// headroom for the interrupt to fire. Record what we can now.

v8_oom::RecordJsStack(isolate,

heap_info + " (at cage limit, stack unavailable)");

LOG(INFO) << "Near V8 cage limit; stack trace capture may not succeed";

}

return new_limit;

}

} // namespace

void RegisterOomStackTraceCallback(v8::Isolate* isolate) {

auto& tls = GetOomState();

if (tls.Get())

return;

auto state = std::make_unique<OomState>();

state->isolate = isolate;

OomState* raw = state.get();

gin::PerIsolateData::From(isolate)->AddDisposeObserver(raw);

tls.Set(std::move(state));

isolate->AddNearHeapLimitCallback(NearHeapLimitCallback, raw);

}

void UnregisterOomStackTraceCallback(v8::Isolate* isolate) {

auto& tls = GetOomState();

OomState* state = tls.Get();

if (!state || state->isolate != isolate)

return;

if (!state->is_in_oom.load()) {

isolate->RemoveNearHeapLimitCallback(NearHeapLimitCallback, 0);

}

gin::PerIsolateData::From(isolate)->RemoveDisposeObserver(state);

tls.Set(nullptr);

}

} // namespace electron

Sunbelt Computer Software

PL/B Language Development and Support

Navigation Menu

Repository navigation

oom_stack_trace.cc

oom_stack_trace.cc

Sunbelt Computer Software

PL/B Language Development and Support

FilesExpand file tree

oom_stack_trace.cc

Latest commit

History

oom_stack_trace.cc

File metadata and controls