comments

esphome/core/application.cpp

@@ -147,14 +147,15 @@ void Application::setup() {
   clear_setup_priority_overrides();
 #endif
 
-#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_WAKE_LOOP_THREADSAFE)
-#ifdef USE_ESP32
-  // Initialize fast select: saves main loop task handle for xTaskNotifyGive wake
+#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_ESP32)
+  // Initialize fast select: saves main loop task handle for xTaskNotifyGive wake.
+  // Always init on ESP32 — the fast path (rcvevent reads + ulTaskNotifyTake) is used
+  // unconditionally when USE_SOCKET_SELECT_SUPPORT is enabled.
   esphome_lwip_fast_select_init();
-#else
-  // Set up wake socket for waking main loop from tasks
-  this->setup_wake_loop_threadsafe_();
 #endif
+#if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_WAKE_LOOP_THREADSAFE) && !defined(USE_ESP32)
+  // Set up wake socket for waking main loop from tasks (non-ESP32 only)
+  this->setup_wake_loop_threadsafe_();
 #endif
 
   this->schedule_dump_config();
@@ -642,7 +643,9 @@ void Application::yield_with_select_(uint32_t delay_ms) {
   ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(delay_ms));
 
 #elif defined(USE_SOCKET_SELECT_SUPPORT)
-  // Non-ESP32 platforms (LibreTiny bk72xx/rtl87xx): use select()
+  // Non-ESP32 select() path (LibreTiny bk72xx/rtl87xx, host platform).
+  // ESP32 is excluded by the #if above — both BSD_SOCKETS and LWIP_SOCKETS on ESP32
+  // use LwIP under the hood, so the fast path handles all ESP32 socket implementations.
   if (!this->socket_fds_.empty()) [[likely]] {
     // Update fd_set if socket list has changed
     if (this->socket_fds_changed_) [[unlikely]] {
@@ -700,7 +703,7 @@ Application App;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
 #ifdef USE_ESP32
 void Application::wake_loop_threadsafe() {
-  // Direct FreeRTOS task notification — ISR-safe, <1 us
+  // Direct FreeRTOS task notification — <1 us, task context only (NOT ISR-safe)
   esphome_lwip_wake_main_loop();
 }
 #else   // !USE_ESP32

esphome/core/lwip_fast_select.c

@@ -130,11 +130,17 @@ void esphome_lwip_hook_socket(int fd) {
   if (sock == NULL || sock->conn == NULL)
     return;
 
-  // Save original callback once — all LwIP sockets share the same event_callback.
+  // Save original callback once — all LwIP sockets share the same static event_callback
+  // (DEFAULT_SOCKET_EVENTCB in sockets.c, used for SOCK_RAW, SOCK_DGRAM, and SOCK_STREAM).
   if (s_original_callback == NULL) {
     s_original_callback = sock->conn->callback;
   }
 
+  // Verify assumption: if we already have the original, this socket should have the same one.
+  // If this fires, LwIP changed to use per-socket callbacks and we need a per-fd array.
+  LWIP_ASSERT("all sockets must share the same event_callback",
+              sock->conn->callback == s_original_callback || sock->conn->callback == esphome_socket_event_callback);
+
   // Replace with our wrapper. Atomic on ESP32 (32-bit aligned pointer write).
   // TCP/IP thread sees either old or new pointer — both are valid.
   sock->conn->callback = esphome_socket_event_callback;

tests/components/socket/test_wake_loop_threadsafe.py

@@ -1,16 +1,21 @@
 from esphome.components import socket
-from esphome.const import KEY_CORE, KEY_TARGET_PLATFORM, PLATFORM_ESP8266
+from esphome.const import (
+    KEY_CORE,
+    KEY_TARGET_PLATFORM,
+    PLATFORM_ESP32,
+    PLATFORM_ESP8266,
+)
 from esphome.core import CORE
 
 
-def _setup_non_esp32_platform() -> None:
-    """Set up CORE.data with a non-ESP32 platform for testing."""
-    CORE.data[KEY_CORE] = {KEY_TARGET_PLATFORM: PLATFORM_ESP8266}
+def _setup_platform(platform=PLATFORM_ESP8266) -> None:
+    """Set up CORE.data with a platform for testing."""
+    CORE.data[KEY_CORE] = {KEY_TARGET_PLATFORM: platform}
 
 
 def test_require_wake_loop_threadsafe__first_call() -> None:
     """Test that first call sets up define and consumes socket."""
-    _setup_non_esp32_platform()
+    _setup_platform()
     CORE.config = {"wifi": True}
     socket.require_wake_loop_threadsafe()
 
@@ -39,7 +44,7 @@ def test_require_wake_loop_threadsafe__idempotent() -> None:
 
 def test_require_wake_loop_threadsafe__multiple_calls() -> None:
     """Test that multiple calls only set up once."""
-    _setup_non_esp32_platform()
+    _setup_platform()
     # Call three times
     CORE.config = {"openthread": True}
     socket.require_wake_loop_threadsafe()
@@ -83,3 +88,29 @@ def test_require_wake_loop_threadsafe__no_networking_does_not_consume_socket() -
     udp_consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS_UDP, {})
     assert "socket.wake_loop_threadsafe" not in udp_consumers
     assert udp_consumers == initial_udp
+
+
+def test_require_wake_loop_threadsafe__esp32_no_udp_socket() -> None:
+    """Test that ESP32 uses task notifications instead of UDP socket."""
+    _setup_platform(PLATFORM_ESP32)
+    CORE.config = {"wifi": True}
+    socket.require_wake_loop_threadsafe()
+
+    # Verify the define was added
+    assert CORE.data[socket.KEY_WAKE_LOOP_THREADSAFE_REQUIRED] is True
+    assert any(d.name == "USE_WAKE_LOOP_THREADSAFE" for d in CORE.defines)
+
+    # Verify no UDP socket was consumed (ESP32 uses FreeRTOS task notifications)
+    udp_consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS_UDP, {})
+    assert "socket.wake_loop_threadsafe" not in udp_consumers
+
+
+def test_require_wake_loop_threadsafe__non_esp32_consumes_udp_socket() -> None:
+    """Test that non-ESP32 platforms consume a UDP socket for wake notifications."""
+    _setup_platform(PLATFORM_ESP8266)
+    CORE.config = {"wifi": True}
+    socket.require_wake_loop_threadsafe()
+
+    # Verify UDP socket was consumed
+    udp_consumers = CORE.data.get(socket.KEY_SOCKET_CONSUMERS_UDP, {})
+    assert udp_consumers.get("socket.wake_loop_threadsafe") == 1