From 25bb3e67f3918bf03a5317da3138204886337347 Mon Sep 17 00:00:00 2001
From: Ryan Ofsky <ryan@ofsky.org>
Date: Wed, 3 Jun 2026 18:59:27 -0400
Subject: [PATCH 1/2] proxy-client: fix TSan data race in clientDestroy

clientDestroy() reads m_context.connection to decide whether to use
MP_LOG vs KJ_LOG, but Connection::~Connection() can set it to null
concurrently from the event loop thread (via the disconnect_cb sync
cleanup callback) while the destructor runs on an async cleanup thread,
causing a TSan-reported data race. The race is exposed by the test added
in commit 90be835 ("test: regression for ~ProxyClient destroy after peer
disconnect").

The KJ_LOG fallback was only needed before commit 315ff53 ("refactor:
Add ProxyContext EventLoop* member"), when logging required going
through connection->m_loop. Since that commit, m_context.loop is a
direct EventLoopRef that is always valid regardless of whether
m_context.connection is null. The KJ_LOG branch is now dead code, so
drop it and the connection check entirely.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 include/mp/proxy-types.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/include/mp/proxy-types.h b/include/mp/proxy-types.h
index 70b05381..2e1460a9 100644
--- a/include/mp/proxy-types.h
+++ b/include/mp/proxy-types.h
@@ -644,11 +644,7 @@ struct CapRequestTraits<::capnp::Request<_Params, _Results>>
 template <typename Client>
 void clientDestroy(Client& client)
 {
-    if (client.m_context.connection) {
-        MP_LOG(*client.m_context.loop, Log::Debug) << "IPC client destroy " << CxxTypeName(client);
-    } else {
-        KJ_LOG(INFO, "IPC interrupted client destroy", CxxTypeName(client));
-    }
+    MP_LOG(*client.m_context.loop, Log::Debug) << "IPC client destroy " << CxxTypeName(client);
 }
 
 template <typename Server>

From 039e5ac14bd8bb8a0532431474fbfd70bf0a2557 Mon Sep 17 00:00:00 2001
From: Ryan Ofsky <ryan@ofsky.org>
Date: Wed, 3 Jun 2026 21:25:02 -0400
Subject: [PATCH 2/2] mpgen: iwyu changes required by previous commit

gen.cpp uses IWYU pragma: keep for include which appears to be necessary for
newer versions of capnproto (1.4.0 but not 1.1.0)
---
 src/mp/gen.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/mp/gen.cpp b/src/mp/gen.cpp
index 29fd8a9e..4232dc84 100644
--- a/src/mp/gen.cpp
+++ b/src/mp/gen.cpp
@@ -6,6 +6,7 @@
 #include <mp/util.h>
 
 #include <algorithm>
+#include <capnp/schema.capnp.h> // IWYU pragma: keep
 #include <capnp/schema.h>
 #include <capnp/schema-parser.h>
 #include <cerrno>
@@ -329,12 +330,15 @@ static void Generate(kj::StringPtr src_prefix,
     cpp_client << "#include <" << include_path << ".h>\n";
     cpp_client << "#include <" << include_path << ".proxy.h>\n";
     cpp_client << "#include <" << include_path << ".proxy-types.h>\n";
+    cpp_client << "#include <capnp/capability.h>\n";
     cpp_client << "#include <capnp/generated-header-support.h>\n";
     cpp_client << "#include <cstring>\n";
-    cpp_client << "#include <vector>\n";
+    cpp_client << "#include <functional>\n";
     cpp_client << "#include <kj/common.h>\n";
+    cpp_client << "#include <map>\n";
     cpp_client << "#include <mp/proxy.h>\n";
     cpp_client << "#include <mp/util.h>\n";
+    cpp_client << "#include <vector>\n";
     cpp_client << "#include <" << PROXY_TYPES << ">\n";
     cpp_client << "// IWYU pragma: end_keep\n\n";
     cpp_client << "namespace mp {\n";
@@ -346,8 +350,6 @@ static void Generate(kj::StringPtr src_prefix,
     cpp_types << "#include <" << include_path << ".h> // IWYU pragma: keep\n";
     cpp_types << "#include <" << include_path << ".proxy.h>\n";
     cpp_types << "#include <" << include_path << ".proxy-types.h> // IWYU pragma: keep\n";
-    cpp_types << "#include <kj/common.h>\n";
-    cpp_types << "#include <mp/util.h>\n";
     cpp_types << "#include <" << PROXY_TYPES << ">\n\n";
     cpp_types << "namespace mp {\n";