esp-idf/components/esp32/esp_timer.c
Ivan Grokhotkov 6e7eb3c776 esp_timer: fix for the case when timer is deleted in callback
Timer callback can delete the timer. If CONFIG_ESP_TIMER_PROFILING was
enabled, this caused an access to invalid (freed) memory.
This fix adds a pointer to track the timer while executing the callback.
This is needed so that we can check if callback deletes the timer,
in which case we won't try updating profiling counters for this timer
after the callback is done.
2017-11-29 11:44:46 +08:00

462 lines
12 KiB
C

// Copyright 2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <sys/param.h>
#include "esp_types.h"
#include "esp_attr.h"
#include "esp_err.h"
#include "esp_timer.h"
#include "esp_task.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/xtensa_api.h"
#include "sdkconfig.h"
#include "esp_timer_impl.h"
#ifdef CONFIG_ESP_TIMER_PROFILING
#define WITH_PROFILING 1
#endif
#ifndef NDEBUG
// Enable built-in checks in queue.h in debug builds
#define INVARIANTS
#endif
#include "rom/queue.h"
#define TIMER_EVENT_QUEUE_SIZE 16
struct esp_timer {
uint64_t alarm;
uint64_t period;
esp_timer_cb_t callback;
void* arg;
#if WITH_PROFILING
const char* name;
size_t times_triggered;
size_t times_armed;
uint64_t total_callback_run_time;
#endif // WITH_PROFILING
LIST_ENTRY(esp_timer) list_entry;
};
static bool is_initialized();
static esp_err_t timer_insert(esp_timer_handle_t timer);
static esp_err_t timer_remove(esp_timer_handle_t timer);
static bool timer_armed(esp_timer_handle_t timer);
static void timer_list_lock();
static void timer_list_unlock();
#if WITH_PROFILING
static void timer_insert_inactive(esp_timer_handle_t timer);
static void timer_remove_inactive(esp_timer_handle_t timer);
#endif // WITH_PROFILING
static const char* TAG = "esp_timer";
// list of currently armed timers
static LIST_HEAD(esp_timer_list, esp_timer) s_timers =
LIST_HEAD_INITIALIZER(s_timers);
#if WITH_PROFILING
// list of unarmed timers, used only to be able to dump statistics about
// all the timers
static LIST_HEAD(esp_inactive_timer_list, esp_timer) s_inactive_timers =
LIST_HEAD_INITIALIZER(s_timers);
// used to keep track of the timer when executing the callback
static esp_timer_handle_t s_timer_in_callback;
#endif
// task used to dispatch timer callbacks
static TaskHandle_t s_timer_task;
// counting semaphore used to notify the timer task from ISR
static SemaphoreHandle_t s_timer_semaphore;
// lock protecting s_timers, s_inactive_timers, s_timer_in_callback
static portMUX_TYPE s_timer_lock = portMUX_INITIALIZER_UNLOCKED;
esp_err_t esp_timer_create(const esp_timer_create_args_t* args,
esp_timer_handle_t* out_handle)
{
if (!is_initialized()) {
return ESP_ERR_INVALID_STATE;
}
if (args->callback == NULL) {
return ESP_ERR_INVALID_ARG;
}
esp_timer_handle_t result = (esp_timer_handle_t) calloc(1, sizeof(*result));
if (result == NULL) {
return ESP_ERR_NO_MEM;
}
result->callback = args->callback;
result->arg = args->arg;
#if WITH_PROFILING
result->name = args->name;
timer_insert_inactive(result);
#endif
*out_handle = result;
return ESP_OK;
}
esp_err_t IRAM_ATTR esp_timer_start_once(esp_timer_handle_t timer, uint64_t timeout_us)
{
if (!is_initialized() || timer_armed(timer)) {
return ESP_ERR_INVALID_STATE;
}
timer->alarm = esp_timer_get_time() + timeout_us;
timer->period = 0;
#if WITH_PROFILING
timer->times_armed++;
#endif
return timer_insert(timer);
}
esp_err_t IRAM_ATTR esp_timer_start_periodic(esp_timer_handle_t timer, uint64_t period_us)
{
if (!is_initialized() || timer_armed(timer)) {
return ESP_ERR_INVALID_STATE;
}
period_us = MAX(period_us, esp_timer_impl_get_min_period_us());
timer->alarm = esp_timer_get_time() + period_us;
timer->period = period_us;
#if WITH_PROFILING
timer->times_armed++;
#endif
return timer_insert(timer);
}
esp_err_t IRAM_ATTR esp_timer_stop(esp_timer_handle_t timer)
{
if (!is_initialized() || !timer_armed(timer)) {
return ESP_ERR_INVALID_STATE;
}
return timer_remove(timer);
}
esp_err_t esp_timer_delete(esp_timer_handle_t timer)
{
if (timer_armed(timer)) {
return ESP_ERR_INVALID_STATE;
}
#if WITH_PROFILING
if (timer == s_timer_in_callback) {
s_timer_in_callback = NULL;
}
timer_remove_inactive(timer);
#endif
if (timer == NULL) {
return ESP_ERR_INVALID_ARG;
}
free(timer);
return ESP_OK;
}
static IRAM_ATTR esp_err_t timer_insert(esp_timer_handle_t timer)
{
timer_list_lock();
#if WITH_PROFILING
timer_remove_inactive(timer);
#endif
esp_timer_handle_t it, last = NULL;
if (LIST_FIRST(&s_timers) == NULL) {
LIST_INSERT_HEAD(&s_timers, timer, list_entry);
} else {
LIST_FOREACH(it, &s_timers, list_entry) {
if (timer->alarm < it->alarm) {
LIST_INSERT_BEFORE(it, timer, list_entry);
break;
}
last = it;
}
if (it == NULL) {
assert(last);
LIST_INSERT_AFTER(last, timer, list_entry);
}
}
if (timer == LIST_FIRST(&s_timers)) {
esp_timer_impl_set_alarm(timer->alarm);
}
timer_list_unlock();
return ESP_OK;
}
static IRAM_ATTR esp_err_t timer_remove(esp_timer_handle_t timer)
{
timer_list_lock();
LIST_REMOVE(timer, list_entry);
timer->alarm = 0;
timer->period = 0;
#if WITH_PROFILING
timer_insert_inactive(timer);
#endif
timer_list_unlock();
return ESP_OK;
}
#if WITH_PROFILING
static IRAM_ATTR void timer_insert_inactive(esp_timer_handle_t timer)
{
/* May be locked or not, depending on where this is called from.
* Lock recursively.
*/
timer_list_lock();
esp_timer_handle_t head = LIST_FIRST(&s_inactive_timers);
if (head == NULL) {
LIST_INSERT_HEAD(&s_inactive_timers, timer, list_entry);
} else {
/* Insert as head element as this is the fastest thing to do.
* Removal is O(1) anyway.
*/
LIST_INSERT_BEFORE(head, timer, list_entry);
}
timer_list_unlock();
}
static IRAM_ATTR void timer_remove_inactive(esp_timer_handle_t timer)
{
timer_list_lock();
LIST_REMOVE(timer, list_entry);
timer_list_unlock();
}
#endif // WITH_PROFILING
static IRAM_ATTR bool timer_armed(esp_timer_handle_t timer)
{
return timer->alarm > 0;
}
static IRAM_ATTR void timer_list_lock()
{
portENTER_CRITICAL(&s_timer_lock);
}
static IRAM_ATTR void timer_list_unlock()
{
portEXIT_CRITICAL(&s_timer_lock);
}
static void timer_process_alarm(esp_timer_dispatch_t dispatch_method)
{
/* unused, provision to allow running callbacks from ISR */
(void) dispatch_method;
timer_list_lock();
uint64_t now = esp_timer_impl_get_time();
esp_timer_handle_t it = LIST_FIRST(&s_timers);
while (it != NULL &&
it->alarm < now) {
LIST_REMOVE(it, list_entry);
if (it->period > 0) {
it->alarm += it->period;
timer_insert(it);
} else {
it->alarm = 0;
#if WITH_PROFILING
timer_insert_inactive(it);
#endif
}
#if WITH_PROFILING
uint64_t callback_start = now;
s_timer_in_callback = it;
#endif
timer_list_unlock();
(*it->callback)(it->arg);
timer_list_lock();
now = esp_timer_impl_get_time();
#if WITH_PROFILING
/* The callback might have deleted the timer.
* If this happens, esp_timer_delete will set s_timer_in_callback
* to NULL.
*/
if (s_timer_in_callback) {
s_timer_in_callback->times_triggered++;
s_timer_in_callback->total_callback_run_time += now - callback_start;
}
#endif
it = LIST_FIRST(&s_timers);
}
esp_timer_handle_t first = LIST_FIRST(&s_timers);
if (first) {
esp_timer_impl_set_alarm(first->alarm);
}
timer_list_unlock();
}
static void timer_task(void* arg)
{
while (true){
int res = xSemaphoreTake(s_timer_semaphore, portMAX_DELAY);
assert(res == pdTRUE);
timer_process_alarm(ESP_TIMER_TASK);
}
}
static void IRAM_ATTR timer_alarm_handler(void* arg)
{
int need_yield;
if (xSemaphoreGiveFromISR(s_timer_semaphore, &need_yield) != pdPASS) {
ESP_EARLY_LOGD(TAG, "timer queue overflow");
return;
}
if (need_yield == pdTRUE) {
portYIELD_FROM_ISR();
}
}
static IRAM_ATTR bool is_initialized()
{
return s_timer_task != NULL;
}
esp_err_t esp_timer_init(void)
{
if (is_initialized()) {
return ESP_ERR_INVALID_STATE;
}
s_timer_semaphore = xSemaphoreCreateCounting(TIMER_EVENT_QUEUE_SIZE, 0);
if (!s_timer_semaphore) {
return ESP_ERR_NO_MEM;
}
int ret = xTaskCreatePinnedToCore(&timer_task, "esp_timer",
ESP_TASK_TIMER_STACK, NULL, ESP_TASK_TIMER_PRIO, &s_timer_task, PRO_CPU_NUM);
if (ret != pdPASS) {
vSemaphoreDelete(s_timer_semaphore);
s_timer_semaphore = NULL;
return ESP_ERR_NO_MEM;
}
esp_err_t err = esp_timer_impl_init(&timer_alarm_handler);
if (err != ESP_OK) {
vTaskDelete(s_timer_task);
s_timer_task = NULL;
vSemaphoreDelete(s_timer_semaphore);
s_timer_semaphore = NULL;
return err;
}
return ESP_OK;
}
esp_err_t esp_timer_deinit(void)
{
if (!is_initialized()) {
return ESP_ERR_INVALID_STATE;
}
/* Check if there are any active timers */
if (!LIST_EMPTY(&s_timers)) {
return ESP_ERR_INVALID_STATE;
}
/* We can only check if there are any timers which are not deleted if
* profiling is enabled.
*/
#if WITH_PROFILING
if (!LIST_EMPTY(&s_inactive_timers)) {
return ESP_ERR_INVALID_STATE;
}
#endif
esp_timer_impl_deinit();
vTaskDelete(s_timer_task);
s_timer_task = NULL;
vSemaphoreDelete(s_timer_semaphore);
s_timer_semaphore = NULL;
return ESP_OK;
}
static void print_timer_info(esp_timer_handle_t t, char** dst, size_t* dst_size)
{
size_t cb = snprintf(*dst, *dst_size,
#if WITH_PROFILING
"%-12s %12lld %12lld %9d %9d %12lld\n",
t->name, t->period, t->alarm,
t->times_armed, t->times_triggered, t->total_callback_run_time);
/* keep this in sync with the format string, used in esp_timer_dump */
#define TIMER_INFO_LINE_LEN 78
#else
"timer@%p %12lld %12lld\n", t, t->period, t->alarm);
#define TIMER_INFO_LINE_LEN 46
#endif
*dst += cb;
*dst_size -= cb;
}
esp_err_t esp_timer_dump(FILE* stream)
{
/* Since timer lock is a critical section, we don't want to print directly
* to stdout, since that may cause a deadlock if stdout is interrupt-driven
* (via the UART driver). Allocate sufficiently large chunk of memory first,
* print to it, then dump this memory to stdout.
*/
esp_timer_handle_t it;
/* First count the number of timers */
size_t timer_count = 0;
timer_list_lock();
LIST_FOREACH(it, &s_timers, list_entry) {
++timer_count;
}
#if WITH_PROFILING
LIST_FOREACH(it, &s_inactive_timers, list_entry) {
++timer_count;
}
#endif
timer_list_unlock();
/* Allocate the memory for this number of timers. Since we have unlocked,
* we may find that there are more timers. There's no bulletproof solution
* for this (can't allocate from a critical section), but we allocate
* slightly more and the output will be truncated if that is not enough.
*/
size_t buf_size = TIMER_INFO_LINE_LEN * (timer_count + 3);
char* print_buf = calloc(1, buf_size + 1);
if (print_buf == NULL) {
return ESP_ERR_NO_MEM;
}
/* Print to the buffer */
timer_list_lock();
char* pos = print_buf;
LIST_FOREACH(it, &s_timers, list_entry) {
print_timer_info(it, &pos, &buf_size);
}
#if WITH_PROFILING
LIST_FOREACH(it, &s_inactive_timers, list_entry) {
print_timer_info(it, &pos, &buf_size);
}
#endif
timer_list_unlock();
/* Print the buffer */
fputs(print_buf, stream);
free(print_buf);
return ESP_OK;
}
int64_t IRAM_ATTR esp_timer_get_time()
{
return (int64_t) esp_timer_impl_get_time();
}