diff --git a/src/wrapper/timer.cc b/src/wrapper/timer.cc
index 4ee4cfb3887..9226b1d5fda 100644
--- a/src/wrapper/timer.cc
+++ b/src/wrapper/timer.cc
@@ -42,10 +42,18 @@ TimerNode *swoole_timer_add(long ms, bool persistent, const TimerCallback &callb
 }
 
 bool swoole_timer_del(TimerNode *tnode) {
+    if (!swoole_timer_is_available()) {
+        swWarn("timer is not available");
+        return false;
+    }
     return SwooleTG.timer->remove(tnode);
 }
 
 void swoole_timer_delay(TimerNode *tnode, long delay_ms) {
+    if (!swoole_timer_is_available()) {
+        swWarn("timer is not available");
+        return;
+    }
     return SwooleTG.timer->delay(tnode, delay_ms);
 }
 
@@ -77,7 +85,7 @@ long swoole_timer_tick(long ms, const TimerCallback &callback, void *private_dat
 
 bool swoole_timer_exists(long timer_id) {
     if (!swoole_timer_is_available()) {
-        swWarn("timer[%ld] is not exists", timer_id);
+        swWarn("timer is not available");
         return false;
     }
     TimerNode *tnode = SwooleTG.timer->get(timer_id);
@@ -85,12 +93,16 @@ bool swoole_timer_exists(long timer_id) {
 }
 
 bool swoole_timer_clear(long timer_id) {
+    if (!swoole_timer_is_available()) {
+        swWarn("timer is not available");
+        return false;
+    }
     return SwooleTG.timer->remove(SwooleTG.timer->get(timer_id));
 }
 
 TimerNode *swoole_timer_get(long timer_id) {
     if (!swoole_timer_is_available()) {
-        swWarn("timer[%ld] is not exists", timer_id);
+        swWarn("timer is not available");
         return nullptr;
     }
     return SwooleTG.timer->get(timer_id);
@@ -98,6 +110,7 @@ TimerNode *swoole_timer_get(long timer_id) {
 
 void swoole_timer_free() {
     if (!swoole_timer_is_available()) {
+        swWarn("timer is not available");
         return;
     }
     delete SwooleTG.timer;
@@ -107,6 +120,7 @@ void swoole_timer_free() {
 
 int swoole_timer_select() {
     if (!swoole_timer_is_available()) {
+        swWarn("timer is not available");
         return SW_ERR;
     }
     return SwooleTG.timer->select();
diff --git a/tests/swoole_runtime/curl_native/timer_coredump.phpt b/tests/swoole_runtime/curl_native/timer_coredump.phpt
new file mode 100644
index 00000000000..0661008833a
--- /dev/null
+++ b/tests/swoole_runtime/curl_native/timer_coredump.phpt
@@ -0,0 +1,34 @@
+--TEST--
+swoole_runtime/curl_native: timer coredump
+--SKIPIF--
+<?php
+require __DIR__ . '/../../include/skipif.inc';
+?>
+--FILE--
+<?php
+require __DIR__ . '/../../include/bootstrap.php';
+
+use Swoole\Runtime;
+
+use function Swoole\Coroutine\run;
+
+Runtime::enableCoroutine(SWOOLE_HOOK_NATIVE_CURL);
+
+function test()
+{
+    $curl = curl_init();
+    curl_setopt($curl, CURLOPT_URL, 'https://httpbin.org/');
+    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
+    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
+    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
+    curl_exec($curl);
+    curl_close($curl);
+}
+
+run('test');
+run('test');
+
+echo "Done\n";
+?>
+--EXPECT--
+Done
diff --git a/thirdparty/php/curl/curl_multi.h b/thirdparty/php/curl/curl_multi.h
index 60347a51e5f..afc15737b18 100644
--- a/thirdparty/php/curl/curl_multi.h
+++ b/thirdparty/php/curl/curl_multi.h
@@ -95,7 +95,7 @@ class cURLMulti {
     }
 
     void del_timer() {
-        if (timer && swoole_event_is_available()) {
+        if (timer) {
             swoole_timer_del(timer);
         }
     }