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[wasm] Fix potential deadlock on profiling runs

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The deadlock occurs when the Isolate is destroyed before a wasm compile
job is finished causing the `WasmEngine::LogCode` to deadlock itself
when the TaskRunner is already in the terminated state.

Change-Id: I36dc68aecbcb2054d7da61d22defd0eff3130f62
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3976515
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Auto-Submit: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83921}
This commit is contained in:
Matthias Liedtke 2022-10-26 10:21:36 +02:00 committed by V8 LUCI CQ
parent 4d95ff1a21
commit ae4280faa3
1 changed files with 47 additions and 29 deletions
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76
src/wasm/wasm-engine.cc
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@ -1085,37 +1085,55 @@ void WasmEngine::RemoveIsolate(Isolate* isolate) {
void WasmEngine::LogCode(base::Vector<WasmCode*> code_vec) {
if (code_vec.empty()) return;
base::MutexGuard guard(&mutex_);
NativeModule* native_module = code_vec[0]->native_module();
DCHECK_EQ(1, native_modules_.count(native_module));
for (Isolate* isolate : native_modules_[native_module]->isolates) {
DCHECK_EQ(1, isolates_.count(isolate));
IsolateInfo* info = isolates_[isolate].get();
if (info->log_codes == false) continue;
if (info->log_codes_task == nullptr) {
auto new_task = std::make_unique<LogCodesTask>(
&mutex_, &info->log_codes_task, isolate, this);
info->log_codes_task = new_task.get();
info->foreground_task_runner->PostTask(std::move(new_task));
}
if (info->code_to_log.empty()) {
isolate->stack_guard()->RequestLogWasmCode();
}
for (WasmCode* code : code_vec) {
DCHECK_EQ(native_module, code->native_module());
code->IncRef();
}
using TaskToSchedule =
std::pair<std::shared_ptr<v8::TaskRunner>, std::unique_ptr<LogCodesTask>>;
std::vector<TaskToSchedule> to_schedule;
{
base::MutexGuard guard(&mutex_);
NativeModule* native_module = code_vec[0]->native_module();
DCHECK_EQ(1, native_modules_.count(native_module));
for (Isolate* isolate : native_modules_[native_module]->isolates) {
DCHECK_EQ(1, isolates_.count(isolate));
IsolateInfo* info = isolates_[isolate].get();
if (info->log_codes == false) continue;
if (info->log_codes_task == nullptr) {
auto new_task = std::make_unique<LogCodesTask>(
&mutex_, &info->log_codes_task, isolate, this);
info->log_codes_task = new_task.get();
// Store the LogCodeTasks to post them outside the WasmEngine::mutex_.
// Posting the task in the mutex can cause the following deadlock (only
// in d8): When d8 shuts down, it sets a terminate to the task runner.
// When the terminate flag in the taskrunner is set, all newly posted
// tasks get destroyed immediately. When the LogCodesTask gets
// destroyed, it takes the WasmEngine::mutex_ lock to deregister itself
// from the IsolateInfo. Therefore, as the LogCodesTask may get
// destroyed immediately when it gets posted, it cannot get posted when
// the WasmEngine::mutex_ lock is held.
to_schedule.emplace_back(info->foreground_task_runner,
std::move(new_task));
}
if (info->code_to_log.empty()) {
isolate->stack_guard()->RequestLogWasmCode();
}
for (WasmCode* code : code_vec) {
DCHECK_EQ(native_module, code->native_module());
code->IncRef();
}
auto script_it = info->scripts.find(native_module);
// If the script does not yet exist, logging will happen later. If the weak
// handle is cleared already, we also don't need to log any more.
if (script_it == info->scripts.end()) continue;
auto& log_entry = info->code_to_log[script_it->second.script_id()];
if (!log_entry.source_url) {
log_entry.source_url = script_it->second.source_url();
auto script_it = info->scripts.find(native_module);
// If the script does not yet exist, logging will happen later. If the
// weak handle is cleared already, we also don't need to log any more.
if (script_it == info->scripts.end()) continue;
auto& log_entry = info->code_to_log[script_it->second.script_id()];
if (!log_entry.source_url) {
log_entry.source_url = script_it->second.source_url();
}
log_entry.code.insert(log_entry.code.end(), code_vec.begin(),
code_vec.end());
}
log_entry.code.insert(log_entry.code.end(), code_vec.begin(),
code_vec.end());
}
for (auto& [runner, task] : to_schedule) {
runner->PostTask(std::move(task));
}
}