From ff4b6949cfb2b842749228208214c894ee62c7d4 Mon Sep 17 00:00:00 2001
From: KonstantinKondrashov <konstantin@espressif.com>
Date: Wed, 16 Mar 2022 19:11:43 +0800
Subject: [PATCH] esp_ipc: Fix a case when ipc_task() can wake up blocking task
 early

Closes https://github.com/espressif/esp-idf/issues/8559
---
 components/esp_ipc/ipc.c           |  8 +++++---
 components/esp_ipc/test/test_ipc.c | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/components/esp_ipc/ipc.c b/components/esp_ipc/ipc.c
index 98331077e5..41659105d9 100644
--- a/components/esp_ipc/ipc.c
+++ b/components/esp_ipc/ipc.c
@@ -65,14 +65,17 @@ static void IRAM_ATTR ipc_task(void* arg)
         }
 #endif
         if (s_func[cpuid]) {
+            // we need to cache s_func, s_func_arg and s_ipc_wait variables locally because they can be changed by a subsequent IPC call.
             esp_ipc_func_t func = s_func[cpuid];
+            s_func[cpuid] = NULL;
             void* arg = s_func_arg[cpuid];
+            esp_ipc_wait_t ipc_wait = s_ipc_wait[cpuid];
 
-            if (s_ipc_wait[cpuid] == IPC_WAIT_FOR_START) {
+            if (ipc_wait == IPC_WAIT_FOR_START) {
                 xSemaphoreGive(s_ipc_ack[cpuid]);
             }
             (*func)(arg);
-            if (s_ipc_wait[cpuid] == IPC_WAIT_FOR_END) {
+            if (ipc_wait == IPC_WAIT_FOR_END) {
                 xSemaphoreGive(s_ipc_ack[cpuid]);
             }
         }
@@ -141,7 +144,6 @@ static esp_err_t esp_ipc_call_and_wait(uint32_t cpu_id, esp_ipc_func_t func, voi
     s_ipc_wait[cpu_id] = wait_for;
     xSemaphoreGive(s_ipc_sem[cpu_id]);
     xSemaphoreTake(s_ipc_ack[cpu_id], portMAX_DELAY);
-    s_func[cpu_id] = NULL;
 #ifdef CONFIG_ESP_IPC_USES_CALLERS_PRIORITY
     xSemaphoreGive(s_ipc_mutex[cpu_id]);
 #else
diff --git a/components/esp_ipc/test/test_ipc.c b/components/esp_ipc/test/test_ipc.c
index 9369b2524d..de19814b82 100644
--- a/components/esp_ipc/test/test_ipc.c
+++ b/components/esp_ipc/test/test_ipc.c
@@ -125,4 +125,30 @@ TEST_CASE("Test multiple ipc_calls", "[ipc]")
 }
 #endif /* CONFIG_ESP_IPC_USE_CALLERS_PRIORITY */
 
+static void test_func_ipc_cb2(void *arg)
+{
+    vTaskDelay(100 / portTICK_PERIOD_MS);
+    int *val = (int *)arg;
+    *val = *val + 1;
+}
+
+static void test_func_ipc_cb3(void *arg)
+{
+    vTaskDelay(500 / portTICK_PERIOD_MS);
+    int *val = (int *)arg;
+    *val = *val + 1;
+}
+
+TEST_CASE("Test ipc_task can not wake up blocking task early", "[ipc]")
+{
+    int val1 = 20;
+    esp_ipc_call(1, test_func_ipc_cb2, &val1);
+    TEST_ASSERT_EQUAL(20, val1);
+
+    int val2 = 30;
+    esp_ipc_call_blocking(1, test_func_ipc_cb3, &val2);
+    TEST_ASSERT_EQUAL(21, val1);
+    TEST_ASSERT_EQUAL(31, val2);
+}
+
 #endif /* !CONFIG_FREERTOS_UNICORE */