diff --git a/src/log.c b/src/log.c
index 52dc58f4..7b2c5a01 100644
--- a/src/log.c
+++ b/src/log.c
@@ -40,7 +40,12 @@
  */
 ATOMIC_T verbose_level = 0;
 
-void (*print_clb)(const struct nc_session *session, NC_VERB_LEVEL level, const char *msg);
+typedef void (*nc_print_clb)(const struct nc_session *session, NC_VERB_LEVEL level, const char *msg);
+
+/**
+ * @brief libnetconf print callback, can be changed while other threads are logging
+ */
+ATOMIC_PTR_T print_clb;
 
 API void
 nc_verbosity(NC_VERB_LEVEL level)
@@ -103,6 +108,7 @@ nc_log_vprintf(const struct nc_session *session, NC_VERB_LEVEL level, const char
     char *msg;
     void *mem;
     int req_len;
+    nc_print_clb clb;
 
     msg = malloc(NC_MSG_SIZE);
     if (!msg) {
@@ -130,8 +136,9 @@ nc_log_vprintf(const struct nc_session *session, NC_VERB_LEVEL level, const char
         }
     }
 
-    if (print_clb) {
-        print_clb(session, level, msg);
+    clb = (nc_print_clb)ATOMIC_PTR_LOAD_RELAXED(print_clb);
+    if (clb) {
+        clb(session, level, msg);
     } else if (session && session->id) {
         fprintf(stderr, "Session %" PRIu32 " %s: %s\n", session->id, verb[level].label, msg);
     } else {
@@ -156,5 +163,5 @@ nc_log_printf(const struct nc_session *session, NC_VERB_LEVEL level, const char
 API void
 nc_set_print_clb_session(void (*clb)(const struct nc_session *, NC_VERB_LEVEL, const char *))
 {
-    print_clb = clb;
+    ATOMIC_PTR_STORE_RELAXED(print_clb, clb);
 }
diff --git a/tests/test_ch.c b/tests/test_ch.c
index f0df4a49..704c4304 100644
--- a/tests/test_ch.c
+++ b/tests/test_ch.c
@@ -100,8 +100,10 @@ server_thread_ssh(void *arg)
 
     /* set print clb so we get access to messages */
     nc_set_print_clb_session(test_msg_callback);
+    pthread_mutex_lock(&msg_lock);
     buffer[0] = '\0';
     strcpy(expected, "reconnecting in");
+    pthread_mutex_unlock(&msg_lock);
 
     /* prepare data for deleting the call-home client */
     ret = nc_server_config_del_ch_client("ch_ssh", &test_data->tree);
@@ -443,8 +445,10 @@ server_thread_delete_while_session(void *arg)
     struct test_ch_data *test_data = test_ctx->test_data;
 
     nc_set_print_clb_session(test_msg_callback);
+    pthread_mutex_lock(&msg_lock);
     buffer[0] = '\0';
     strcpy(expected, "thread exit");
+    pthread_mutex_unlock(&msg_lock);
 
     ps = nc_ps_new();
     assert_non_null(ps);