Update

Author: sanchda

ddtrace/internal/datadog/profiling/stack_v2/include/sampler.hpp

@@ -25,9 +25,6 @@ class Sampler
     // Parameters
     uint64_t echion_frame_cache_size = g_default_echion_frame_cache_size;
 
-    // Helper function; implementation of the echion sampling thread
-    void sampling_thread(const uint64_t seq_num);
-
     // This is a singleton, so no public constructor
     Sampler();
 
@@ -37,7 +34,7 @@ class Sampler
   public:
     // Singleton instance
     static Sampler& get();
-    void start();
+    bool start();
     void stop();
     void register_thread(uint64_t id, uint64_t native_id, const char* name);
     void unregister_thread(uint64_t id);
@@ -46,6 +43,7 @@ class Sampler
                       PyObject* _asyncio_scheduled_tasks,
                       PyObject* _asyncio_eager_tasks);
     void link_tasks(PyObject* parent, PyObject* child);
+    void sampling_thread(const uint64_t seq_num);
 
     // The Python side dynamically adjusts the sampling rate based on overhead, so we need to be able to update our
     // own intervals accordingly.  Rather than a preemptive measure, we assume the rate is ~fairly stable and just

ddtrace/internal/datadog/profiling/stack_v2/src/sampler.cpp

@@ -10,44 +10,47 @@
 
 using namespace Datadog;
 
-
 // Helper class for spawning a std::thread with control over its default stack size
 #ifdef __linux__
-#include <unistd.h>
 #include <sys/resource.h>
-template <typename Function, typename... Args>
-pthread_t create_thread_with_stack(size_t stack_size, Function&& f, Args&&... args) {
+#include <unistd.h>
+
+struct ThreadArgs
+{
+    Sampler* sampler;
+    uint64_t seq_num;
+};
+
+void*
+call_sampling_thread(void* args)
+{
+    ThreadArgs* thread_args = static_cast<ThreadArgs*>(args);
+    Sampler* sampler = thread_args->sampler;
+    sampler->sampling_thread(thread_args->seq_num);
+    return nullptr;
+}
+
+pthread_t
+create_thread_with_stack(size_t stack_size, Sampler* sampler, uint64_t seq_num)
+{
     pthread_attr_t attr;
-    pthread_attr_init(&attr);
+    if (pthread_attr_init(&attr) != 0) {
+        return 0;
+    }
     if (stack_size > 0) {
         pthread_attr_setstacksize(&attr, stack_size);
     }
 
-    // DAS: I think std::bind here is necessary?
-    pthread_t thread;
-    auto* thread_func = new auto(
-        std::bind(std::forward<Function>(f), std::forward<Args>(args)...)
-    );
-
-    int ret = pthread_create(
-        &thread,
-        &attr,
-        [](void* arg) -> void* {
-            auto* func = static_cast<decltype(thread_func)>(arg);
-            (*func)();
-            delete func;
-            return nullptr;
-        },
-        thread_func
-    );
+    pthread_t thread_id;
+    ThreadArgs thread_args = { sampler, seq_num };
+    int ret = pthread_create(&thread_id, &attr, call_sampling_thread, &thread_args);
 
     pthread_attr_destroy(&attr);
 
     if (ret != 0) {
-        delete thread_func;
-        throw std::runtime_error("Failed to create thread");
+        return 0;
     }
-    return thread;
+    return thread_id;
 }
 #endif
 
@@ -175,7 +178,7 @@ Sampler::unregister_thread(uint64_t id)
     thread_info_map.erase(id);
 }
 
-void
+bool
 Sampler::start()
 {
     static std::once_flag once;
@@ -188,11 +191,18 @@ Sampler::start()
     // We might as well get the default stack size and use that
     rlimit stack_sz = {};
     getrlimit(RLIMIT_STACK, &stack_sz);
-    create_thread_with_stack(stack_sz.rlim_cur, &Sampler::sampling_thread, this, ++thread_seq_num); // leak the thread
+    if (create_thread_with_stack(stack_sz.rlim_cur, this, ++thread_seq_num) == 0) {
+        return false;
+    }
 #else
-    std::thread t(&Sampler::sampling_thread, this, ++thread_seq_num);
-    t.detach();
+    try {
+        std::thread t(&Sampler::sampling_thread, this, ++thread_seq_num);
+        t.detach();
+    } catch (const std::exception& e) {
+        return false;
+    }
 #endif
+    return true;
 }
 
 void

ddtrace/internal/datadog/profiling/stack_v2/src/stack_v2.cpp

@@ -21,8 +21,10 @@ _stack_v2_start(PyObject* self, PyObject* args, PyObject* kwargs)
     }
 
     Sampler::get().set_interval(min_interval_s);
-    Sampler::get().start();
-    Py_RETURN_NONE;
+    if (Sampler::get().start()) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
 }
 
 // Bypasses the old-style cast warning with an unchecked helper function