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fix: deadlock on Windows when destroying non-AudioWorklet worker contexts

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The previous change kept the WebWorkerObserver alive across
ContextWillDestroy so the worker thread could be reused for the next
context (AudioWorklet thread pooling, Chromium CL:5270028). This is
correct for AudioWorklet but wrong for PaintWorklet and other worker
types, which Blink does not pool — each teardown destroys the thread.

For those worker types, ~NodeBindings was deferred to the thread-exit
TLS callback. By that point set_uv_env(nullptr) had already run, so on
Windows the embed thread was parked in GetQueuedCompletionStatus with a
stale async_sent latch that swallowed the eventual WakeupEmbedThread()
from ~NodeBindings. uv_thread_join then blocked forever, deadlocking
renderer navigation. The worker-multiple-destroy crash case timed out
on win-x64/x86/arm64 as a result. macOS/Linux (epoll/kqueue) don't have
the latch and were unaffected.

Plumb is_audio_worklet from WillDestroyWorkerContextOnWorkerThread into
ContextWillDestroy. For non-AudioWorklet contexts, restore the
pre-existing behavior of calling lazy_tls->Set(nullptr) at the end of
the last-context cleanup so ~NodeBindings runs while the worker thread
is still healthy. AudioWorklet continues to keep the observer alive so
the next pooled context can share NodeBindings.
This commit is contained in:
Shelley Vohr
2026-04-07 12:40:14 +02:00
parent 2b633ebe40
commit 7273708ab4
3 changed files with 25 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
shell/renderer/electron_renderer_client.cc
View File

@@ -246,7 +246,7 @@ void ElectronRendererClient::WillDestroyWorkerContextOnWorkerThread(
auto* current = WebWorkerObserver::GetCurrent();
if (current)
current->ContextWillDestroy(context);
current->ContextWillDestroy(context, ec->IsAudioWorkletGlobalScope());
}
void ElectronRendererClient::SetUpWebAssemblyTrapHandler() {

32
shell/renderer/web_worker_observer.cc
View File

@@ -204,7 +204,8 @@ void WebWorkerObserver::ShareEnvironmentWithContext(
}
}
void WebWorkerObserver::ContextWillDestroy(v8::Local<v8::Context> context) {
void WebWorkerObserver::ContextWillDestroy(v8::Local<v8::Context> context,
bool is_audio_worklet) {
node::Environment* env = node::Environment::GetCurrent(context);
if (!env)
return;
@@ -252,15 +253,26 @@ void WebWorkerObserver::ContextWillDestroy(v8::Local<v8::Context> context) {
// ElectronBindings is tracking node environments.
electron_bindings_->EnvironmentDestroyed(env);
// Do NOT destroy the observer here. The worker thread may be reused
// for another worklet context (e.g., AudioWorklet thread pooling or
// PaintWorklet after page reload). Destroying the observer would
// force a new NodeBindings to be created, but Node.js cannot be
// fully reinitialized on the same thread (the allocator shim can
// only be loaded once). Instead, keep the observer and its
// NodeBindings alive so they can be reused. The environments_ set
// is now empty, so WorkerScriptReadyForEvaluation will call
// InitializeNewEnvironment on the next context.
// For non-AudioWorklet contexts (e.g., PaintWorklet, dedicated workers)
// Blink does not pool the worker thread, so tear down the observer
// synchronously while the worker thread is still in a clean state.
// Deferring teardown to the thread-exit TLS callback hangs on Windows:
// after set_uv_env(nullptr) the embed thread parks in
// GetQueuedCompletionStatus and the later WakeupEmbedThread() from
// ~NodeBindings can be lost, causing uv_thread_join to block forever
// and the renderer to deadlock during navigation.
//
// For AudioWorklet, threads are pooled (Chromium CL:5270028) and the
// same NodeBindings/embed thread must be reused for the next context
// on the thread because Node.js cannot be re-initialized on the same
// thread (the allocator shim can only be loaded once). In that case
// we keep the observer alive and let the next
// WorkerScriptReadyForEvaluation call InitializeNewEnvironment on the
// (now empty) environments_ set.
if (!is_audio_worklet) {
lazy_tls->Set(nullptr); // destroys *this; do not access members below
return;
}
} else {
// Other contexts still use the shared environment. Just unassign
// this context from the environment if it's not the primary context

3
shell/renderer/web_worker_observer.h
View File

@@ -37,7 +37,8 @@ class WebWorkerObserver {
WebWorkerObserver& operator=(const WebWorkerObserver&) = delete;
void WorkerScriptReadyForEvaluation(v8::Local<v8::Context> context);
void ContextWillDestroy(v8::Local<v8::Context> context);
void ContextWillDestroy(v8::Local<v8::Context> context,
bool is_audio_worklet);
private:
// Full initialization for the first context on a thread.