diff --git a/qemu-nbd.c b/qemu-nbd.c index 05b61da51e..ed5895861b 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -852,10 +852,6 @@ int main(int argc, char **argv) export_name = ""; } - if (!trace_init_backends()) { - exit(1); - } - trace_init_file(); qemu_set_log(LOG_TRACE, &error_fatal); socket_activation = check_socket_activation(); @@ -1045,6 +1041,18 @@ int main(int argc, char **argv) #endif /* WIN32 */ } + /* + * trace_init must be done after daemonization. Why? Because at + * least the simple backend spins up a helper thread as well as an + * atexit() handler that waits on that thread, but the helper + * thread won't survive a fork, leading to deadlock in the child + * if we initialized pre-fork. + */ + if (!trace_init_backends()) { + exit(1); + } + trace_init_file(); + if (opts.device != NULL && sockpath == NULL) { sockpath = g_malloc(128); snprintf(sockpath, 128, SOCKET_PATH, basename(opts.device));