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Race condition in the inspector calls WriteRaw() on nullptr #34833

Description

@trevnorris
  • Version: v12.18.3
  • Platform: Linux 4.19.127 x86_64
  • Subsystem: inspector

NOTE: Unable to reproduce this in v14.8.0.

What steps will reproduce the bug?

A race condition causing the process to abort can be triggered by running test-inspector-wait-for-connection.js in a loop.

To make things easier, first apply this patch:

diff --git a/src/inspector_socket.cc b/src/inspector_socket.cc
index a7019281af..b9d7f85507 100644
--- a/src/inspector_socket.cc
+++ b/src/inspector_socket.cc
@@ -609,6 +609,7 @@ ProtocolHandler::ProtocolHandler(InspectorSocket* inspector,
 
 int ProtocolHandler::WriteRaw(const std::vector<char>& buffer,
                               uv_write_cb write_cb) {
+  CHECK_NOT_NULL(tcp_);
   return tcp_->WriteRaw(buffer, write_cb);
 }

Fortunately this can be reproduced with a debug build. So I use the following to reproduce it:

for i in $(seq 1 1000)
  do echo -ne "$i\r"
  ./out/Debug/node test/parallel/test-inspector-wait-for-connection.js > /dev/null
  if [[ $? -ne 0 ]] || [[ -f "./core" ]]; then
    break
  fi
done

How often does it reproduce? Is there a required condition?

Usually triggers the abort within running the test every 100 times.

Additional information

The specific issue is that ProtocolHandler::WriteRaw() attempts a write to tcp_ when tcp_ == 0x0.

Additional debug information from lldb:

(lldb) bt
* thread #1, name = 'node', stop reason = signal SIGABRT
    ...
    frame #3: node`node::Assert(info=0x0000000002c5d938) at node_errors.cc:253:3
    frame #4: node`node::inspector::ProtocolHandler::WriteRaw(this=0x00007f9c680011b0, buffer=size=1, write_cb=(node`node::inspector::(anonymous namespace)::WriteRequest::Cleanup(uv_write_s*, int) at inspector_socket.cc:123))(uv_write_s*, int)) at inspector_socket.cc:612:3
    frame #5: node`node::inspector::(anonymous namespace)::WsHandler::Write(this=0x00007f9c680011b0, data=<unavailable>) at inspector_socket.cc:351:5
    frame #6: node`node::inspector::InspectorSocket::Write(this=0x00007f9c68001740, data="{\"method\":\"Runtime.executionContextDestroyed\",\"params\":{\"executionContextId\":1}}", len=80) at inspector_socket.cc:769:22
    frame #7: node`node::inspector::SocketSession::Send(this=0x00007f9c680015f0, message=") at inspector_socket_server.cc:495:15
    frame #8: node`node::inspector::InspectorSocketServer::Send(this=0x00007f9c84a7e9f8, session_id=1, message=") at inspector_socket_server.cc:481:14
    ...

(lldb) f 4
frame #4: 0x0000000000ff2017 node`node::inspector::ProtocolHandler::WriteRaw(this=0x00007f9c680011b0, buffer=size=1, write_cb=(node`node::inspector::(anonymous namespace)::WriteRequest::Cleanup(uv_write_s*, int) at inspector_socket.cc:123))(uv_write_s*, int)) at inspector_socket.cc:612:3
   609 
   610  int ProtocolHandler::WriteRaw(const std::vector<char>& buffer,
   611                                uv_write_cb write_cb) {
-> 612    CHECK_NOT_NULL(tcp_);
   613    return tcp_->WriteRaw(buffer, write_cb);
   614  }
   615

(lldb) fr v
(node::inspector::(anonymous namespace)::WsHandler *) this = 0x00007f9c680011b0
(const std::vector<char, std::allocator<char> > &) buffer = size=1: {
  std::_Vector_base<char, std::allocator<char> > = {
    _M_impl = (_M_start = "\x81P{\"method\":\"Runtime.executionContextDestroyed\",\"params\":{\"executionContextId\":1}}", _M_finish = "", _M_end_of_storage = "")
  }
}
(uv_write_cb) write_cb = 0x0000000000ff4790 (node`node::inspector::(anonymous namespace)::WriteRequest::Cleanup(uv_write_s*, int) at inspector_socket.cc:123)


(lldb) p tcp_
(node::inspector::TcpHolder::Pointer) $0 = nullptr {
  pointer = 0x0000000000000000
}

Activity

  1. added
    inspectorIssues and PRs related to the V8 inspector protocol.
    on Aug 19, 2020
  2. github-actions commented on Jun 27, 2026

    @github-actions
    Contributor

    This issue has been marked as stale due to 210 days of inactivity.
    It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.

  3. added
    staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.
    on Jun 27, 2026
  4. removed
    staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.
    on Jun 30, 2026
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