From 9bf2851414658f35026505a363627aaf3a1faa10 Mon Sep 17 00:00:00 2001
From: "haibo.chen" <495810242@qq.com>
Date: Thu, 16 Oct 2025 13:54:41 +0800
Subject: [PATCH] fix crash issue caused by reload configuration file, which
 occurs when a vhost is added/removed in the new configuration.

---
 trunk/src/app/srs_app_config.cpp     |  6 +++++
 trunk/src/utest/srs_utest_reload.cpp | 36 ++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index d541a625b..12f9ac8e4 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -1509,6 +1509,12 @@ srs_error_t SrsConfig::reload_conf(SrsConfig *conf)
         SrsConfDirective *old_vhost = old_root->get("vhost", vhost);
         SrsConfDirective *new_vhost = root_->get("vhost", vhost);
 
+        // Only compare config when both old and new vhost exist.
+        // @see https://github.com/ossrs/srs/issues/4529
+        if (!old_vhost || !new_vhost) {
+            continue;
+        }
+
         // chunk_size, only one per vhost.
         if (!srs_directive_equals(new_vhost->get("chunk_size"), old_vhost->get("chunk_size"))) {
             for (it = subscribes_.begin(); it != subscribes_.end(); ++it) {
diff --git a/trunk/src/utest/srs_utest_reload.cpp b/trunk/src/utest/srs_utest_reload.cpp
index 11abf8c82..2d342e3ed 100644
--- a/trunk/src/utest/srs_utest_reload.cpp
+++ b/trunk/src/utest/srs_utest_reload.cpp
@@ -111,3 +111,39 @@ VOID TEST(ConfigReloadTest, ReloadVhostChunkSize)
     EXPECT_EQ(1, handler.count_true());
     handler.reset();
 }
+
+VOID TEST(ConfigReloadTest, ReloadAddNewVhost)
+{
+    srs_error_t err = srs_success;
+
+    MockReloadHandler handler;
+    MockSrsReloadConfig conf;
+
+    conf.subscribe(&handler);
+    // Start with one vhost
+    HELPER_EXPECT_SUCCESS(conf.mock_parse(_MIN_OK_CONF "vhost ossrs.net { chunk_size 60000; }"));
+
+    // Add a new vhost - should not crash
+    HELPER_EXPECT_SUCCESS(conf.do_reload(_MIN_OK_CONF "vhost ossrs.net { chunk_size 60000; } vhost new_vhost { chunk_size 65536; }"));
+    // Handler should not be triggered for new vhost
+    EXPECT_TRUE(handler.all_false());
+    handler.reset();
+}
+
+VOID TEST(ConfigReloadTest, ReloadRemoveVhost)
+{
+    srs_error_t err = srs_success;
+
+    MockReloadHandler handler;
+    MockSrsReloadConfig conf;
+
+    conf.subscribe(&handler);
+    // Start with two vhosts
+    HELPER_EXPECT_SUCCESS(conf.mock_parse(_MIN_OK_CONF "vhost ossrs.net { chunk_size 60000; } vhost old_vhost { chunk_size 65536; }"));
+
+    // Remove old_vhost - should not crash
+    HELPER_EXPECT_SUCCESS(conf.do_reload(_MIN_OK_CONF "vhost ossrs.net { chunk_size 60000; }"));
+    // Handler should not be triggered for removed vhost
+    EXPECT_TRUE(handler.all_false());
+    handler.reset();
+}