Fix the race condition while calling rcl_shutdown (#1353)

* Fix the race condition while calling rcl_shutdown Signed-off-by: Barry Xu <[email protected]> * Avoid calling rcl_shutdown() multiple times on the same context Signed-off-by: Barry Xu <[email protected]> * Multiple calls to Context::shutdown will throw an exception Signed-off-by: Barry Xu <[email protected]> * Update the name of an exception Signed-off-by: Barry Xu <[email protected]> --------- Signed-off-by: Barry Xu <[email protected]>
ros2 · Nov 8, 2024 · 34f9e13 · 34f9e13
1 parent 53d7760
commit 34f9e13
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Showing 3 changed files with 17 additions and 10 deletions.
diff --git a/rclpy/src/rclpy/context.cpp b/rclpy/src/rclpy/context.cpp
@@ -150,17 +150,18 @@ Context::ok()
 void
 Context::shutdown()
 {
-  {
-    std::lock_guard<std::mutex> guard{g_contexts_mutex};
-    auto iter = std::find(g_contexts.begin(), g_contexts.end(), rcl_context_.get());
-    if (iter != g_contexts.end()) {
-      g_contexts.erase(iter);
-    }
+  std::lock_guard<std::mutex> guard{g_contexts_mutex};
+  if (already_shutdown_) {
+    throw ContextAlreadyShutdown("Context already shutdown.");
   }
-
-  rcl_ret_t ret = rcl_shutdown(rcl_context_.get());
-  if (RCL_RET_OK != ret) {
-    throw RCLError("failed to shutdown");
+  auto iter = std::find(g_contexts.begin(), g_contexts.end(), rcl_context_.get());
+  if (iter != g_contexts.end()) {
+    g_contexts.erase(iter);
+    rcl_ret_t ret = rcl_shutdown(rcl_context_.get());
+    if (RCL_RET_OK != ret) {
+      throw RCLError("failed to shutdown");
+    }
+    already_shutdown_ = true;
   }
 }
 

diff --git a/rclpy/src/rclpy/context.hpp b/rclpy/src/rclpy/context.hpp
@@ -101,6 +101,7 @@ class Context : public Destroyable, public std::enable_shared_from_this<Context>
 
 private:
   std::shared_ptr<rcl_context_t> rcl_context_;
+  bool already_shutdown_{false};
 };
 
 /// Define a pybind11 wrapper for an rclpy::Context

diff --git a/rclpy/src/rclpy/exceptions.hpp b/rclpy/src/rclpy/exceptions.hpp
@@ -80,6 +80,11 @@ class InvalidHandle : public std::runtime_error
   using std::runtime_error::runtime_error;
 };
 
+class ContextAlreadyShutdown : public std::runtime_error
+{
+  using std::runtime_error::runtime_error;
+};
+
 }  // namespace rclpy
 
 #endif  // RCLPY__EXCEPTIONS_HPP_