feat(esp_system): Add esp_backtrace_print_all_tasks()

This commit adds esp_backtrace_print_all_tasks() which prints the backtraces
of all tasks at runtime.

Closes https://github.com/espressif/esp-idf/issues/9708
CLoses https://github.com/espressif/esp-idf/pull/11575

[Omar Chebib: Prevent task switching while printing backtraces of tasks.]
[Omar Chebib: Ensure all task stacks are flushed from register to RAM.]
[Omar Chebib: Removed esp_task_snapshot_to_backtrace_frame() as task snapshot is private API.]
[Omar Chebib: Added test case for esp_backtrace_print_all_tasks().]

Signed-off-by: Omar Chebib <omar.chebib@espressif.com>

components/esp_system/test_apps/esp_system_unity_tests/main/test_backtrace.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -10,12 +10,14 @@
  */
 #include <stdlib.h>
 #include "unity.h"
+#include "test_utils.h"
 
 #if __XTENSA__
 
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "xtensa_api.h" // Replace with interrupt allocator API (IDF-3891)
+#include "esp_debug_helpers.h"
 #include "esp_intr_alloc.h"
 #include "esp_rom_sys.h"
 #include "esp_rom_uart.h"
@@ -26,6 +28,8 @@
 #define RECUR_DEPTH             3
 #define ACTION_ABORT            -1
 #define ACTION_INT_WDT          -2
+#define TASK_PRIORITY           5
+
 
 // Set to (-1) for abort(), (-2) for interrupt watchdog
 static int backtrace_trigger_source;
@@ -118,4 +122,32 @@ TEST_CASE_MULTIPLE_STAGES("Test backtrace with a ROM function", "[reset_reason][
                            do_rom_crash,
                            check_reset_reason_panic)
 
+
+#define NUM_TEST_FUNCS      2
+
+static void backtrace_suspend_func(void *arg)
+{
+    // Simply suspend and wait to be deleted
+    vTaskSuspend(NULL);
+}
+
+TEST_CASE("Test esp_backtrace_print_all_tasks()", "[esp_system]")
+{
+    TaskHandle_t task_handles[NUM_TEST_FUNCS];
+
+    for (int i = 0; i < NUM_TEST_FUNCS; i++) {
+        // Create multiple unpinned tasks at higher priorities
+        xTaskCreate(backtrace_suspend_func, "trace_func", 2048, NULL, UNITY_FREERTOS_PRIORITY + i + 1, &task_handles[i]);
+    }
+    // Short delay to allow tasks to suspend
+    vTaskDelay(10);
+    // Print backtraces of all tasks
+    esp_backtrace_print_all_tasks(3);
+
+    // Clean up tasks
+    for (int i = 0; i < NUM_TEST_FUNCS; i++) {
+        vTaskDelete(task_handles[i]);
+    }
+}
+
 #endif