Reconnecting the inspector causes a segmentation fault

[penalosa]

This is likely due to 19c8ed5, but I haven't been able to fully pin it down.

Essentially, in the latest version of workerd, connecting, disconnecting, and then reconnecting to the inspector causes a segmentation fault:

workerd/util/symbolizer.c++:96: warning: Not symbolizing stack traces because $LLVM_SYMBOLIZER is not set. To symbolize stack traces, set $LLVM_SYMBOLIZER to the location of the llvm-symbolizer binary. When running tests under bazel, use `--test_env=LLVM_SYMBOLIZER=<path>`.
*** Received signal #11: Segmentation fault: 11
stack: 

It's pretty easy to reproduce. Run:

npx workerd@latest serve samples/helloworld/config.capnp --inspector-addr=localhost:8989

and open up https://devtools.devprod.cloudflare.dev/js_app?ws=localhost:8989/main. Reloading that webpage twice will result in a segmentation fault.

the same problem doesn't present with the previous version of workerd:

npx [email protected] serve samples/helloworld/config.capnp --inspector-addr=localhost:8989

[jasnell]

Same issue but slightly more useful error:

workerd/server/server.c++:1227: info: Inspector client attaching [main]
workerd/util/symbolizer.c++:96: warning: Not symbolizing stack traces because $LLVM_SYMBOLIZER is not set. To symbolize stack traces, set $LLVM_SYMBOLIZER to the location of the llvm-symbolizer binary. When running tests under bazel, use `--test_env=LLVM_SYMBOLIZER=<path>`.
workerd/server/server.c++:1194: error: Uncaught exception: kj/_virtual_includes/kj/kj/memory.h:433: failed: expected ptr != nullptr; null Own<> dereference
stack: /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@b9f9874 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@462b7c1 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@b94c3c0 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@46284bc /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@554a5b2 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@557dda0 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@473bbb4 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@473bde2 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@a5f901d /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@a5fe901 /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@a60320d /home/jsnell/.cache/bazel/_bazel_jsnell/53c6c64186779d616175192445f45b10/execroot/workerd/bazel-out/k8-fastbuild/bin/src/workerd/server/workerd@a552540

Symbolizing the stack yields...

kj::_::inlineRequireFailure(char const*, int, char const*, char const*, char const*) at ??:0:0

kj::Own<kj::_::PromiseNode, kj::_::PromiseDisposer>::operator->() at workerd.c++:0:0

kj::_::CoroutineBase::AwaiterBase::awaitSuspendImpl(kj::_::CoroutineBase&) at ??:0:0

bool kj::_::Coroutine<void>::Awaiter<void>::await_suspend<kj::_::Coroutine<void>>(std::__1::coroutine_handle<kj::_::Coroutine<void>>) at workerd.c++:0:0

workerd::XThreadNotifier::awaitNotification() at worker.c++:0:0

workerd::Worker::Isolate::InspectorChannelImpl::WebSocketIoHandler::dispatchLoop() (.resume) at worker.c++:0:0

workerd::server::Server::InspectorService::request(kj::HttpMethod, kj::StringPtr, kj::HttpHeaders const&, kj::AsyncInputStream&, kj::HttpService::Response&) (.resume) at server.c++:0:0

workerd::server::Server::InspectorService::request(kj::HttpMethod, kj::StringPtr, kj::HttpHeaders const&, kj::AsyncInputStream&, kj::HttpService::Response&) (.resume) at server.c++:0:0

kj::HttpServer::Connection::onRequest(kj::HttpHeaders::Request&) (.resume) at http.c++:0:0

kj::HttpServer::Connection::onHeaders(kj::OneOf<kj::HttpHeaders::Request, kj::HttpHeaders::ConnectRequest, kj::HttpHeaders::ProtocolError>&&) (.resume) at http.c++:0:0

kj::HttpServer::Connection::loop() (.resume) at http.c++:0:0

kj::HttpServer::Connection::startLoopImpl()::'lambda'(kj::Exception&&)::operator()(kj::Exception&&) const at http.c++:0:0

[jasnell]

The revert has landed