diff --git a/spa/include/spa/utils/json-builder.h b/spa/include/spa/utils/json-builder.h
index b41ea9774..abbdb76eb 100644
--- a/spa/include/spa/utils/json-builder.h
+++ b/spa/include/spa/utils/json-builder.h
@@ -17,6 +17,7 @@
 #include <spa/utils/defs.h>
 #include <spa/utils/ansi.h>
 #include <spa/utils/json.h>
+#include <spa/utils/cleanup.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -108,10 +109,16 @@ SPA_API_JSON_BUILDER int spa_json_builder_membuf(struct spa_json_builder *b,
 	return spa_json_builder_file(b, f, flags | SPA_JSON_BUILDER_FLAG_CLOSE);
 }
 
-SPA_API_JSON_BUILDER void spa_json_builder_close(struct spa_json_builder *b)
+SPA_API_JSON_BUILDER int spa_json_builder_close(struct spa_json_builder *b)
 {
-	if (b->flags & SPA_JSON_BUILDER_FLAG_CLOSE)
-		fclose(b->f);
+	int res = 0;
+	if (b->flags & SPA_JSON_BUILDER_FLAG_CLOSE) {
+		if (ferror(b->f))
+			res = -EIO;
+		if (fclose(b->f) != 0 && res == 0)
+			res = -errno;
+	}
+	return res;
 }
 
 SPA_API_JSON_BUILDER int spa_json_builder_encode_string(struct spa_json_builder *b,
@@ -422,16 +429,18 @@ void spa_json_builder_array_valuef(struct spa_json_builder *b, bool recurse, con
 SPA_API_JSON_BUILDER char *spa_json_builder_reformat(const char *json, uint32_t flags)
 {
 	struct spa_json_builder b;
-	char *mem;
+	spa_autofree char *mem = NULL;
 	size_t size;
 	int res;
-	if ((res = spa_json_builder_memstream(&b, &mem, &size, flags)) < 0) {
-		errno = -res;
-		return NULL;
-	}
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, flags)) < 0)
+		goto error;
 	spa_json_builder_array_value(&b, true, json);
-	spa_json_builder_close(&b);
-	return mem;
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto error;
+	return spa_steal_ptr(mem);
+error:
+	errno = -res;
+	return NULL;
 }
 
 /**
diff --git a/src/modules/module-avb/maap.c b/src/modules/module-avb/maap.c
index b053c08d3..4e138983d 100644
--- a/src/modules/module-avb/maap.c
+++ b/src/modules/module-avb/maap.c
@@ -4,6 +4,7 @@
 
 #include <unistd.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 
 #include <pipewire/pipewire.h>
@@ -299,7 +300,7 @@ static int load_state(struct maap *maap)
 static int save_state(struct maap *maap)
 {
 	struct spa_json_builder b;
-	char *ptr;
+	spa_autofree char *ptr = NULL;
 	size_t size;
 	char key[512];
 	uint32_t count;
@@ -317,10 +318,10 @@ static int save_state(struct maap *maap)
 	spa_json_builder_object_uint(&b,    "count", maap->count);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "]");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	count = pw_properties_set(maap->props, "maap.addresses", ptr);
-	free(ptr);
 
 	if (count > 0) {
 		snprintf(key, sizeof(key), "maap.%s", maap->server->ifname);
diff --git a/src/modules/module-jackdbus-detect.c b/src/modules/module-jackdbus-detect.c
index 11ad5bdb3..5a85ce46a 100644
--- a/src/modules/module-jackdbus-detect.c
+++ b/src/modules/module-jackdbus-detect.c
@@ -15,6 +15,7 @@
 
 #include <dbus/dbus.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/string.h>
 #include <spa/utils/result.h>
 #include <spa/utils/json-builder.h>
@@ -118,7 +119,7 @@ static const struct pw_impl_module_events tunnelmodule_events = {
 static int load_jack_tunnel(struct impl *impl)
 {
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res = 0;
 
@@ -131,13 +132,13 @@ static int load_jack_tunnel(struct impl *impl)
 	if (impl->properties != NULL)
 		pw_properties_serialize_dict(b.f, &impl->properties->dict, 0);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto done;
 
 	pw_log_info("loading module args:'%s'", args);
 	impl->jack_tunnel = pw_context_load_module(impl->context,
 			"libpipewire-module-jack-tunnel",
 			args, NULL);
-	free(args);
 
 	if (impl->jack_tunnel == NULL) {
 		res = -errno;
diff --git a/src/modules/module-parametric-equalizer.c b/src/modules/module-parametric-equalizer.c
index 9f0ef7247..2f042372f 100644
--- a/src/modules/module-parametric-equalizer.c
+++ b/src/modules/module-parametric-equalizer.c
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <limits.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/utils/json-builder.h>
 #include <spa/param/audio/raw.h>
@@ -164,7 +165,7 @@ static int enhance_properties(struct pw_properties *props, const char *key, ...)
 {
 	struct spa_json_builder b;
 	spa_autoptr(pw_properties) p = NULL;
-	char *args = NULL;
+	spa_autofree char *args = NULL;
 	const char *str;
 	size_t size;
         va_list varargs;
@@ -192,10 +193,10 @@ static int enhance_properties(struct pw_properties *props, const char *key, ...)
 		return res;
 	}
 	pw_properties_serialize_dict(b.f, &p->dict, PW_PROPERTIES_FLAG_ENCLOSE);
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	pw_properties_set(props, key, args);
-	free(args);
 	return 0;
 }
 
@@ -203,7 +204,7 @@ static int create_eq_filter(struct impl *impl, const char *filename)
 {
 	struct spa_json_builder b;
 	const char* str;
-	char *args = NULL;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int32_t res = 0;
 
@@ -237,13 +238,13 @@ static int create_eq_filter(struct impl *impl, const char *filename)
 	spa_json_builder_pop(&b,          "}");
 	pw_properties_serialize_dict(b.f, &impl->props->dict, 0);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	pw_log_info("loading new module-filter-chain with args: %s", args);
 	impl->eq_module = pw_context_load_module(impl->context,
 				"libpipewire-module-filter-chain",
 				args, NULL);
-	free(args);
 
 	if (!impl->eq_module) {
 		pw_log_error("Can't load module: %m");
diff --git a/src/modules/module-protocol-pulse/format.c b/src/modules/module-protocol-pulse/format.c
index ac531f89d..913cfe996 100644
--- a/src/modules/module-protocol-pulse/format.c
+++ b/src/modules/module-protocol-pulse/format.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2020 Wim Taymans */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/string.h>
 #include <spa/debug/types.h>
 #include <spa/param/audio/format.h>
@@ -704,7 +705,7 @@ static int add_int(struct format_info *info, const char *k, struct spa_pod *para
 	case SPA_CHOICE_Enum:
 	{
 		struct spa_json_builder b;
-		char *ptr;
+		spa_autofree char *ptr = NULL;
 		size_t size;
 		int res;
 
@@ -715,10 +716,10 @@ static int add_int(struct format_info *info, const char *k, struct spa_pod *para
 		for (i = 1; i < n_values; i++)
 			spa_json_builder_array_int(&b, values[i]);
 		spa_json_builder_pop(&b, "]");
-		spa_json_builder_close(&b);
+		if ((res = spa_json_builder_close(&b)) < 0)
+			return res;
 
 		pw_properties_set(info->props, k, ptr);
-		free(ptr);
 		break;
 	}
 	default:
diff --git a/src/modules/module-protocol-pulse/modules/module-always-sink.c b/src/modules/module-protocol-pulse/modules/module-always-sink.c
index 2641068be..b07155288 100644
--- a/src/modules/module-protocol-pulse/modules/module-always-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-always-sink.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2022 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
 
@@ -54,7 +55,7 @@ static int module_always_sink_load(struct module *module)
 {
 	struct module_always_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	const char *str;
 	size_t size;
 	int res;
@@ -66,12 +67,12 @@ static int module_always_sink_load(struct module *module)
 	if ((str = pw_properties_get(module->props, "sink_name")) != NULL)
 		spa_json_builder_object_string(&b, "sink.name", str);
 	spa_json_builder_pop(&b, "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-fallback-sink",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-combine-sink.c b/src/modules/module-protocol-pulse/modules/module-combine-sink.c
index 2ad776fc4..9b4dc236c 100644
--- a/src/modules/module-protocol-pulse/modules/module-combine-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-combine-sink.c
@@ -4,6 +4,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json.h>
 #include <spa/utils/json-builder.h>
 
@@ -171,7 +172,7 @@ static int module_combine_sink_load(struct module *module)
 	struct spa_json_builder b;
 	uint32_t i;
 	int res;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 
 	data->core = pw_context_connect(module->impl->context, NULL, 0);
@@ -217,12 +218,12 @@ static int module_combine_sink_load(struct module *module)
 	spa_json_builder_pop(&b,             "}");
 	spa_json_builder_pop(&b,          "]");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-combine-stream",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-echo-cancel.c b/src/modules/module-protocol-pulse/modules/module-echo-cancel.c
index 0bff4627d..3722a45d7 100644
--- a/src/modules/module-protocol-pulse/modules/module-echo-cancel.c
+++ b/src/modules/module-protocol-pulse/modules/module-echo-cancel.c
@@ -4,6 +4,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -104,7 +105,7 @@ static int module_echo_cancel_load(struct module *module)
 {
 	struct module_echo_cancel_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -134,12 +135,12 @@ static int module_echo_cancel_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b, "}");
 	spa_json_builder_pop(&b, "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-echo-cancel",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
@@ -198,7 +199,7 @@ static int rename_geometry(struct pw_properties *props, const char *pa_key, cons
 {
 	const char *str;
 	int i = 0, len, res;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	struct spa_json_builder b;
 
@@ -231,10 +232,10 @@ static int rename_geometry(struct pw_properties *props, const char *pa_key, cons
 		i++;
 	}
 	spa_json_builder_pop(&b, "]");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	pw_properties_set(props, pw_key, args);
-	free(args);
 
 	pw_properties_set(props, pa_key, NULL);
 	return 0;
diff --git a/src/modules/module-protocol-pulse/modules/module-jackdbus-detect.c b/src/modules/module-protocol-pulse/modules/module-jackdbus-detect.c
index 9a7db0c8c..adeb86b28 100644
--- a/src/modules/module-protocol-pulse/modules/module-jackdbus-detect.c
+++ b/src/modules/module-protocol-pulse/modules/module-jackdbus-detect.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -88,7 +89,7 @@ static int module_jackdbus_detect_load(struct module *module)
 {
 	struct module_jackdbus_detect_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -109,12 +110,12 @@ static int module_jackdbus_detect_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->sink_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-jackdbus-detect",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-ladspa-sink.c b/src/modules/module-protocol-pulse/modules/module-ladspa-sink.c
index 6b0ae0bf7..c439ed9e5 100644
--- a/src/modules/module-protocol-pulse/modules/module-ladspa-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-ladspa-sink.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <spa/param/audio/format-utils.h>
@@ -92,7 +93,7 @@ static int module_ladspa_sink_load(struct module *module)
 {
 	struct module_ladspa_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	const char *str, *plugin, *label;
 	size_t size;
 	int res;
@@ -159,12 +160,12 @@ static int module_ladspa_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-filter-chain",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-ladspa-source.c b/src/modules/module-protocol-pulse/modules/module-ladspa-source.c
index 80284f267..35a088c2b 100644
--- a/src/modules/module-protocol-pulse/modules/module-ladspa-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-ladspa-source.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <spa/param/audio/format-utils.h>
@@ -92,7 +93,7 @@ static int module_ladspa_source_load(struct module *module)
 {
 	struct module_ladspa_source_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	const char *str, *plugin, *label;
 	size_t size;
 	int res;
@@ -159,12 +160,12 @@ static int module_ladspa_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-filter-chain",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-loopback.c b/src/modules/module-protocol-pulse/modules/module-loopback.c
index 0a732251a..665f4a844 100644
--- a/src/modules/module-protocol-pulse/modules/module-loopback.c
+++ b/src/modules/module-protocol-pulse/modules/module-loopback.c
@@ -4,6 +4,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -87,7 +88,7 @@ static int module_loopback_load(struct module *module)
 {
 	struct module_loopback_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -108,12 +109,12 @@ static int module_loopback_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-loopback",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-native-protocol-tcp.c b/src/modules/module-protocol-pulse/modules/module-native-protocol-tcp.c
index c3c8f6a0a..3d9293438 100644
--- a/src/modules/module-protocol-pulse/modules/module-native-protocol-tcp.c
+++ b/src/modules/module-protocol-pulse/modules/module-native-protocol-tcp.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
 
@@ -87,7 +88,7 @@ static int module_native_protocol_tcp_prepare(struct module * const module)
 	struct pw_properties * const props = module->props;
 	const char *port, *listen, *auth;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -111,10 +112,10 @@ static int module_native_protocol_tcp_prepare(struct module * const module)
 		spa_json_builder_object_string(&b, "client.access", "unrestricted");
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "]");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	pw_properties_set(props, "pulse.tcp", args);
-	free(args);
 
 	d->module = module;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-pipe-sink.c b/src/modules/module-protocol-pulse/modules/module-pipe-sink.c
index 2e50cbe87..a38046f83 100644
--- a/src/modules/module-protocol-pulse/modules/module-pipe-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-pipe-sink.c
@@ -7,6 +7,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
 #include <spa/param/audio/format-utils.h>
@@ -84,7 +85,7 @@ static int module_pipe_sink_load(struct module *module)
 {
 	struct module_pipesink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -100,14 +101,13 @@ static int module_pipe_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->stream_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-pipe-tunnel",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-pipe-source.c b/src/modules/module-protocol-pulse/modules/module-pipe-source.c
index e1ccc9bb6..0375d4aad 100644
--- a/src/modules/module-protocol-pulse/modules/module-pipe-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-pipe-source.c
@@ -7,6 +7,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
 #include <spa/param/audio/format-utils.h>
@@ -82,7 +83,7 @@ static int module_pipe_source_load(struct module *module)
 {
 	struct module_pipesrc_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -98,14 +99,13 @@ static int module_pipe_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->stream_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-pipe-tunnel",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-raop-discover.c b/src/modules/module-protocol-pulse/modules/module-raop-discover.c
index 49cde85a8..f5c97f860 100644
--- a/src/modules/module-protocol-pulse/modules/module-raop-discover.c
+++ b/src/modules/module-protocol-pulse/modules/module-raop-discover.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -61,7 +62,7 @@ static int module_raop_discover_load(struct module *module)
 {
 	struct module_raop_discover_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -72,14 +73,13 @@ static int module_raop_discover_load(struct module *module)
 	if (data->latency_msec > 0)
 		spa_json_builder_object_uint(&b, "raop.latency.ms", data->latency_msec);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-raop-discover",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-remap-sink.c b/src/modules/module-protocol-pulse/modules/module-remap-sink.c
index 7ade38b37..c23cb00cc 100644
--- a/src/modules/module-protocol-pulse/modules/module-remap-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-remap-sink.c
@@ -3,6 +3,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -83,7 +84,7 @@ static int module_remap_sink_load(struct module *module)
 {
 	struct module_remap_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -104,12 +105,12 @@ static int module_remap_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-loopback",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-remap-source.c b/src/modules/module-protocol-pulse/modules/module-remap-source.c
index 173b58b5b..5e08d180e 100644
--- a/src/modules/module-protocol-pulse/modules/module-remap-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-remap-source.c
@@ -3,6 +3,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -83,7 +84,7 @@ static int module_remap_source_load(struct module *module)
 {
 	struct module_remap_source_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -104,12 +105,12 @@ static int module_remap_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-loopback",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-roc-sink-input.c b/src/modules/module-protocol-pulse/modules/module-roc-sink-input.c
index 11af62a89..ff0bbe5a8 100644
--- a/src/modules/module-protocol-pulse/modules/module-roc-sink-input.c
+++ b/src/modules/module-protocol-pulse/modules/module-roc-sink-input.c
@@ -3,6 +3,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Sanchayan Maity <sanchayan@asymptotic.io> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -82,7 +83,7 @@ static int module_roc_sink_input_load(struct module *module)
 {
 	struct module_roc_sink_input_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -98,14 +99,13 @@ static int module_roc_sink_input_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->source_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-roc-source",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-roc-sink.c b/src/modules/module-protocol-pulse/modules/module-roc-sink.c
index 7aaea3209..dbb18b1cc 100644
--- a/src/modules/module-protocol-pulse/modules/module-roc-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-roc-sink.c
@@ -3,6 +3,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Sanchayan Maity <sanchayan@asymptotic.io> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -78,7 +79,7 @@ static int module_roc_sink_load(struct module *module)
 {
 	struct module_roc_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -94,14 +95,13 @@ static int module_roc_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->sink_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-roc-sink",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-roc-source.c b/src/modules/module-protocol-pulse/modules/module-roc-source.c
index 36ec415a0..1beab7843 100644
--- a/src/modules/module-protocol-pulse/modules/module-roc-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-roc-source.c
@@ -3,6 +3,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Sanchayan Maity <sanchayan@asymptotic.io> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -82,7 +83,7 @@ static int module_roc_source_load(struct module *module)
 {
 	struct module_roc_source_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -98,14 +99,13 @@ static int module_roc_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->source_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-roc-source",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-rtp-recv.c b/src/modules/module-protocol-pulse/modules/module-rtp-recv.c
index 34a0d1348..1668ee3c3 100644
--- a/src/modules/module-protocol-pulse/modules/module-rtp-recv.c
+++ b/src/modules/module-protocol-pulse/modules/module-rtp-recv.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2022 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -70,7 +71,7 @@ static int module_rtp_recv_load(struct module *module)
 {
 	struct module_rtp_recv_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -97,14 +98,13 @@ static int module_rtp_recv_load(struct module *module)
 	spa_json_builder_pop(&b,            "}");
 	spa_json_builder_pop(&b,          "]");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-rtp-sap",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/modules/module-rtp-send.c b/src/modules/module-protocol-pulse/modules/module-rtp-send.c
index 863ad4ac5..acdfd019e 100644
--- a/src/modules/module-protocol-pulse/modules/module-rtp-send.c
+++ b/src/modules/module-protocol-pulse/modules/module-rtp-send.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2022 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -107,7 +108,7 @@ static int module_rtp_send_load(struct module *module)
 {
 	struct module_rtp_send_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -123,12 +124,12 @@ static int module_rtp_send_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->stream_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-rtp-sink",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
@@ -156,12 +157,12 @@ static int module_rtp_send_load(struct module *module)
 	spa_json_builder_pop(&b,            "}");
 	spa_json_builder_pop(&b,          "]");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->sap = pw_context_load_module(module->impl->context,
 			"libpipewire-module-rtp-sap",
 			args, NULL);
-	free(args);
 
 	if (data->sap == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-simple-protocol-tcp.c b/src/modules/module-protocol-pulse/modules/module-simple-protocol-tcp.c
index d56be34bb..7c342846a 100644
--- a/src/modules/module-protocol-pulse/modules/module-simple-protocol-tcp.c
+++ b/src/modules/module-protocol-pulse/modules/module-simple-protocol-tcp.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/impl.h>
 #include <pipewire/pipewire.h>
@@ -85,7 +86,7 @@ static int module_simple_protocol_tcp_load(struct module *module)
 	struct module_simple_protocol_tcp_data *data = module->user_data;
 	struct impl *impl = module->impl;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -95,12 +96,12 @@ static int module_simple_protocol_tcp_load(struct module *module)
 	spa_json_builder_array_push(&b, "{");
 	pw_properties_serialize_dict(b.f, &data->module_props->dict, 0);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(impl->context,
 			"libpipewire-module-protocol-simple",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
@@ -187,7 +188,7 @@ static int module_simple_protocol_tcp_prepare(struct module * const module)
 
 	{
 		struct spa_json_builder ab;
-		char *addr;
+		spa_autofree char *addr = NULL;
 		size_t addr_size;
 
 		if ((res = spa_json_builder_memstream(&ab, &addr, &addr_size, 0)) < 0)
@@ -197,10 +198,10 @@ static int module_simple_protocol_tcp_prepare(struct module * const module)
 		spa_json_builder_array_stringf(&ab, "tcp:%s%s%s",
 				listen ? listen : "", listen ? ":" : "", port);
 		spa_json_builder_pop(&ab,        "]");
-		spa_json_builder_close(&ab);
+		if ((res = spa_json_builder_close(&ab)) < 0)
+			goto out;
 
 		pw_properties_set(module_props, "server.address", addr);
-		free(addr);
 	}
 
 	d->module = module;
diff --git a/src/modules/module-protocol-pulse/modules/module-stream-restore.c b/src/modules/module-protocol-pulse/modules/module-stream-restore.c
index ff29c2dbf..24dda6568 100644
--- a/src/modules/module-protocol-pulse/modules/module-stream-restore.c
+++ b/src/modules/module-protocol-pulse/modules/module-stream-restore.c
@@ -71,6 +71,7 @@ enum {
 #include <stdlib.h>
 #include <string.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/defs.h>
 #include <spa/utils/dict.h>
 #include <spa/utils/string.h>
@@ -272,7 +273,7 @@ static int do_extension_stream_restore_write(struct module *module, struct clien
 		struct volume vol;
 		bool mute = false;
 		uint32_t i;
-		char *ptr;
+		spa_autofree char *ptr = NULL;
 		size_t size;
 		char key[1024];
 
@@ -319,7 +320,8 @@ static int do_extension_stream_restore_write(struct module *module, struct clien
 		    (client->default_sink == NULL || !spa_streq(device_name, client->default_sink)))
 			spa_json_builder_object_string(&b, "target-node", device_name);
 		spa_json_builder_pop(&b, "}");
-		spa_json_builder_close(&b);
+		if ((bres = spa_json_builder_close(&b)) < 0)
+			return bres;
 		}
 		if (key_from_name(name, key, sizeof(key)) >= 0) {
 			pw_log_debug("%s -> %s: %s", name, key, ptr);
@@ -328,7 +330,6 @@ static int do_extension_stream_restore_write(struct module *module, struct clien
 							PW_ID_CORE, key, "Spa:String:JSON", "%s", ptr)) < 0)
 				pw_log_warn("failed to set metadata %s = %s, %s", key, ptr, strerror(-res));
 		}
-		free(ptr);
 	}
 
 	return reply_simple_ack(client, tag);
diff --git a/src/modules/module-protocol-pulse/modules/module-switch-on-connect.c b/src/modules/module-protocol-pulse/modules/module-switch-on-connect.c
index 27fef289b..03bfe9bb4 100644
--- a/src/modules/module-protocol-pulse/modules/module-switch-on-connect.c
+++ b/src/modules/module-protocol-pulse/modules/module-switch-on-connect.c
@@ -3,6 +3,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Pauli Virtanen <pav@iki.fi> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <spa/utils/string.h>
@@ -144,21 +145,21 @@ static void manager_added(void *data, struct pw_manager_object *o)
 
 	{
 		struct spa_json_builder b;
-		char *val;
+		spa_autofree char *val = NULL;
 		size_t val_size;
 
 		if (spa_json_builder_memstream(&b, &val, &val_size, 0) >= 0) {
 			spa_json_builder_array_push(&b,  "{");
 			spa_json_builder_object_string(&b, "name", name);
 			spa_json_builder_pop(&b,         "}");
-			spa_json_builder_close(&b);
+			if (spa_json_builder_close(&b) < 0)
+				return;
 
 			pw_manager_set_metadata(d->manager, d->metadata_default,
 					PW_ID_CORE,
 					pw_manager_object_is_sink(o) ? METADATA_CONFIG_DEFAULT_SINK
 						: METADATA_CONFIG_DEFAULT_SOURCE,
 					"Spa:String:JSON", "%s", val);
-			free(val);
 		}
 	}
 }
diff --git a/src/modules/module-protocol-pulse/modules/module-tunnel-sink.c b/src/modules/module-protocol-pulse/modules/module-tunnel-sink.c
index 1340cbd9a..5ee9ccf65 100644
--- a/src/modules/module-protocol-pulse/modules/module-tunnel-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-tunnel-sink.c
@@ -3,6 +3,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 
@@ -86,7 +87,7 @@ static int module_tunnel_sink_load(struct module *module)
 {
 	struct module_tunnel_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -102,12 +103,12 @@ static int module_tunnel_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->stream_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-pulse-tunnel",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-tunnel-source.c b/src/modules/module-protocol-pulse/modules/module-tunnel-source.c
index e494e9263..1bcef7293 100644
--- a/src/modules/module-protocol-pulse/modules/module-tunnel-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-tunnel-source.c
@@ -3,6 +3,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 
@@ -86,7 +87,7 @@ static int module_tunnel_source_load(struct module *module)
 {
 	struct module_tunnel_source_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -102,12 +103,12 @@ static int module_tunnel_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->stream_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-pulse-tunnel",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-virtual-sink.c b/src/modules/module-protocol-pulse/modules/module-virtual-sink.c
index c69026d2f..3dd14bbbf 100644
--- a/src/modules/module-protocol-pulse/modules/module-virtual-sink.c
+++ b/src/modules/module-protocol-pulse/modules/module-virtual-sink.c
@@ -3,6 +3,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -78,7 +79,7 @@ static int module_virtual_sink_load(struct module *module)
 {
 	struct module_virtual_sink_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -99,12 +100,12 @@ static int module_virtual_sink_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-loopback",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-virtual-source.c b/src/modules/module-protocol-pulse/modules/module-virtual-source.c
index eda8b59fe..250f283b8 100644
--- a/src/modules/module-protocol-pulse/modules/module-virtual-source.c
+++ b/src/modules/module-protocol-pulse/modules/module-virtual-source.c
@@ -4,6 +4,7 @@
 /* SPDX-License-Identifier: MIT */
 
 #include <spa/param/audio/format-utils.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -81,7 +82,7 @@ static int module_virtual_source_load(struct module *module)
 {
 	struct module_virtual_source_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -102,12 +103,12 @@ static int module_virtual_source_load(struct module *module)
 	pw_properties_serialize_dict(b.f, &data->playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-loopback",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-x11-bell.c b/src/modules/module-protocol-pulse/modules/module-x11-bell.c
index e1150d6c0..3ecefc31e 100644
--- a/src/modules/module-protocol-pulse/modules/module-x11-bell.c
+++ b/src/modules/module-protocol-pulse/modules/module-x11-bell.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2022 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
 
@@ -65,7 +66,7 @@ static int module_x11_bell_load(struct module *module)
 {
 	struct module_x11_bell_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	const char *str;
 	size_t size;
 	int res;
@@ -83,12 +84,12 @@ static int module_x11_bell_load(struct module *module)
 	if ((str = pw_properties_get(module->props, "xauthority")) != NULL)
 		spa_json_builder_object_string(&b, "x11.xauthority", str);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-x11-bell",
 			args, NULL);
-	free(args);
 
 	if (data->mod == NULL)
 		return -errno;
diff --git a/src/modules/module-protocol-pulse/modules/module-zeroconf-discover.c b/src/modules/module-protocol-pulse/modules/module-zeroconf-discover.c
index 1b3479a40..5384382fb 100644
--- a/src/modules/module-protocol-pulse/modules/module-zeroconf-discover.c
+++ b/src/modules/module-protocol-pulse/modules/module-zeroconf-discover.c
@@ -2,6 +2,7 @@
 /* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
 /* SPDX-License-Identifier: MIT */
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/hook.h>
 #include <spa/utils/json-builder.h>
 #include <pipewire/pipewire.h>
@@ -64,7 +65,7 @@ static int module_zeroconf_discover_load(struct module *module)
 {
 	struct module_zeroconf_discover_data *data = module->user_data;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res;
 
@@ -75,14 +76,13 @@ static int module_zeroconf_discover_load(struct module *module)
 	if (data->latency_msec > 0)
 		spa_json_builder_object_uint(&b, "pulse.latency", data->latency_msec);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	data->mod = pw_context_load_module(module->impl->context,
 			"libpipewire-module-zeroconf-discover",
 			args, NULL);
 
-	free(args);
-
 	if (data->mod == NULL)
 		return -errno;
 
diff --git a/src/modules/module-protocol-pulse/pulse-server.c b/src/modules/module-protocol-pulse/pulse-server.c
index b6c6bf1f6..1fa6318b8 100644
--- a/src/modules/module-protocol-pulse/pulse-server.c
+++ b/src/modules/module-protocol-pulse/pulse-server.c
@@ -4825,7 +4825,7 @@ static int do_set_default(struct client *client, uint32_t command, uint32_t tag,
 		}
 
 		struct spa_json_builder b;
-		char *val;
+		spa_autofree char *val = NULL;
 		size_t val_size;
 
 		if ((res = spa_json_builder_memstream(&b, &val, &val_size, 0)) < 0)
@@ -4834,13 +4834,13 @@ static int do_set_default(struct client *client, uint32_t command, uint32_t tag,
 		spa_json_builder_array_push(&b, "{");
 		spa_json_builder_object_string(&b, "name", name);
 		spa_json_builder_pop(&b,        "}");
-		spa_json_builder_close(&b);
+		if ((res = spa_json_builder_close(&b)) < 0)
+			return res;
 
 		res = pw_manager_set_metadata(manager, client->metadata_default,
 				PW_ID_CORE,
 				sink ? METADATA_CONFIG_DEFAULT_SINK : METADATA_CONFIG_DEFAULT_SOURCE,
 				"Spa:String:JSON", "%s", val);
-		free(val);
 	} else {
 		res = pw_manager_set_metadata(manager, client->metadata_default,
 				PW_ID_CORE,
diff --git a/src/modules/module-protocol-simple.c b/src/modules/module-protocol-simple.c
index b7e982b6e..99123d229 100644
--- a/src/modules/module-protocol-simple.c
+++ b/src/modules/module-protocol-simple.c
@@ -19,6 +19,7 @@
 
 #include "config.h"
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/utils/string.h>
 #include <spa/utils/json-builder.h>
@@ -962,7 +963,7 @@ int pipewire__module_init(struct pw_impl_module *module, const char *args)
 	struct impl *impl;
 	struct server *s;
 	struct spa_json_builder b;
-	char *str;
+	spa_autofree char *str = NULL;
 	size_t size;
 	int res;
 	struct spa_dict_item it[1];
@@ -1017,14 +1018,13 @@ int pipewire__module_init(struct pw_impl_module *module, const char *args)
 				ipv4 ? "" : "[", ip, ipv4 ? "" : "]", port);
 	}
 	spa_json_builder_pop(&b, "]");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto error_free;
 
 	pw_log_info("listening on %s", str);
 	it[0] = SPA_DICT_ITEM_INIT("server.address", str);
 	pw_impl_module_update_properties(module, &SPA_DICT_INIT_ARRAY(it));
 
-	free(str);
-
 	return 0;
 
 error_free:
diff --git a/src/modules/module-raop-discover.c b/src/modules/module-raop-discover.c
index 33ec653e8..561a45316 100644
--- a/src/modules/module-raop-discover.c
+++ b/src/modules/module-raop-discover.c
@@ -12,6 +12,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/utils/string.h>
 #include <spa/utils/json-builder.h>
@@ -233,7 +234,7 @@ static int create_stream(struct impl *impl, struct pw_properties *props,
 		struct tunnel *t)
 {
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res = 0;
 	struct pw_impl_module *mod;
@@ -246,13 +247,13 @@ static int create_stream(struct impl *impl, struct pw_properties *props,
 	spa_json_builder_array_push(&b, "{");
 	pw_properties_serialize_dict(b.f, &props->dict, 0);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto done;
 
 	pw_log_info("loading module args:'%s'", args);
 	mod = pw_context_load_module(impl->context,
 			"libpipewire-module-raop-sink",
 			args, NULL);
-	free(args);
 
 	if (mod == NULL) {
 		res = -errno;
diff --git a/src/modules/module-rtp-sap.c b/src/modules/module-rtp-sap.c
index 452bc18fc..712a6b643 100644
--- a/src/modules/module-rtp-sap.c
+++ b/src/modules/module-rtp-sap.c
@@ -1257,7 +1257,7 @@ static int session_load_source(struct session *session, struct pw_properties *pr
 	struct impl *impl = session->impl;
 	struct pw_context *context = pw_impl_module_get_context(impl->module);
 	struct spa_json_builder b;
-	char *args = NULL;
+	spa_autofree char *args = NULL;
 	size_t size;
 	const char *str, *media;
 	int res;
@@ -1323,15 +1323,14 @@ static int session_load_source(struct session *session, struct pw_properties *pr
 	pw_properties_serialize_dict(b.f, &props->dict, 0);
 	spa_json_builder_pop(&b,         "}");
 	spa_json_builder_pop(&b,       "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	pw_log_info("loading new RTP source");
 	session->module = pw_context_load_module(context,
 				"libpipewire-module-rtp-source",
 				args, NULL);
 
-	free(args);
-
 	if (session->module == NULL) {
 		pw_log_error("Can't load module: %m");
 		return -errno;
@@ -1344,7 +1343,6 @@ static int session_load_source(struct session *session, struct pw_properties *pr
 	return 0;
 error:
 	spa_json_builder_close(&b);
-	free(args);
 	return res;
 }
 
diff --git a/src/modules/module-sendspin-recv.c b/src/modules/module-sendspin-recv.c
index 796520ce8..14f0f02b8 100644
--- a/src/modules/module-sendspin-recv.c
+++ b/src/modules/module-sendspin-recv.c
@@ -18,6 +18,7 @@
 #include <spa/utils/hook.h>
 #include <spa/utils/result.h>
 #include <spa/utils/ringbuffer.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/defs.h>
 #include <spa/utils/dll.h>
 #include <spa/utils/json.h>
@@ -426,10 +427,11 @@ static int send_client_hello(struct client *client)
 	struct impl *impl = client->impl;
 	struct spa_json_builder b;
 	int res;
-	char *mem;
+	spa_autofree char *mem = NULL;
 	size_t size;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "client/hello");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -447,10 +449,10 @@ static int send_client_hello(struct client *client)
 	add_playerv1_support(client, &b);
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(client->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(client->conn, mem, size);
 
 	return res;
 }
@@ -459,10 +461,11 @@ static int send_client_state(struct client *client)
 {
 	struct spa_json_builder b;
 	int res;
-	char *mem;
+	spa_autofree char *mem = NULL;
 	size_t size;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "client/state");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -473,10 +476,10 @@ static int send_client_state(struct client *client)
 	spa_json_builder_pop(&b,             "}");
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(client->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(client->conn, mem, size);
 	return res;
 }
 
@@ -498,17 +501,18 @@ static int send_client_time(struct client *client)
 
 	now = get_time_us(client);
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "client/time");
 	spa_json_builder_object_push(&b,   "payload", "{");
 	spa_json_builder_object_uint(&b,     "client_transmitted", now);
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(client->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(client->conn, mem, size);
 	return res;
 }
 
@@ -528,21 +532,22 @@ static int send_client_goodbye(struct client *client, const char *reason)
 {
 	struct spa_json_builder b;
 	int res;
-	char *mem;
+	spa_autofree char *mem = NULL;
 	size_t size;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "client/goodbye");
 	spa_json_builder_object_push(&b,   "payload", "{");
 	spa_json_builder_object_string(&b,   "reason", reason);
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	res = pw_websocket_connection_send_text(client->conn, mem, size);
 	pw_websocket_connection_disconnect(client->conn, true);
-	free(mem);
 	return res;
 }
 
diff --git a/src/modules/module-sendspin-send.c b/src/modules/module-sendspin-send.c
index c47497656..48f758ec5 100644
--- a/src/modules/module-sendspin-send.c
+++ b/src/modules/module-sendspin-send.c
@@ -18,6 +18,7 @@
 #include <spa/utils/hook.h>
 #include <spa/utils/result.h>
 #include <spa/utils/ringbuffer.h>
+#include <spa/utils/cleanup.h>
 #include <spa/utils/defs.h>
 #include <spa/utils/dll.h>
 #include <spa/utils/json.h>
@@ -427,7 +428,8 @@ static int send_server_hello(struct client *c)
 	size_t size;
 	char *mem;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,   "{");
 	spa_json_builder_object_string(&b,  "type", "server/hello");
 	spa_json_builder_object_push(&b,    "payload", "{");
@@ -443,10 +445,10 @@ static int send_server_hello(struct client *c)
 	spa_json_builder_object_string(&b,    "connection_reason", "discovery");
 	spa_json_builder_pop(&b,            "}");
 	spa_json_builder_pop(&b,          "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 
 	return res;
 }
@@ -461,7 +463,8 @@ static int send_server_state(struct client *c)
 	if (!SPA_FLAG_IS_SET(c->supported_roles, ROLE_METADATA))
 		return 0;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "server/state");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -470,10 +473,10 @@ static int send_server_state(struct client *c)
 	spa_json_builder_pop(&b,             "}");
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 	return res;
 }
 
@@ -487,7 +490,8 @@ static int send_server_time(struct client *c, uint64_t t1, uint64_t t2)
 
 	t3 = get_time_us(c);
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "server/time");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -496,10 +500,10 @@ static int send_server_time(struct client *c, uint64_t t1, uint64_t t2)
 	spa_json_builder_object_uint(&b,     "server_transmitted", t3);
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 	return res;
 }
 
@@ -511,7 +515,8 @@ static int send_server_command(struct client *c, int command, int value)
 	char *mem;
 	int res;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,   "{");
 	spa_json_builder_object_string(&b,  "type", "server/command");
 	spa_json_builder_object_push(&b,    "payload", "{");
@@ -526,10 +531,10 @@ static int send_server_command(struct client *c, int command, int value)
 	spa_json_builder_pop(&b,              "}");
 	spa_json_builder_pop(&b,            "}");
 	spa_json_builder_pop(&b,          "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 	return res;
 }
 #endif
@@ -572,7 +577,8 @@ static int send_stream_start(struct client *c)
 		return -ENOTSUP;
 	}
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,   "{");
 	spa_json_builder_object_string(&b,  "type", "stream/start");
 	spa_json_builder_object_push(&b,    "payload", "{");
@@ -585,10 +591,10 @@ static int send_stream_start(struct client *c)
 	spa_json_builder_pop(&b,              "}");
 	spa_json_builder_pop(&b,            "}");
 	spa_json_builder_pop(&b,          "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 	return res;
 }
 
@@ -600,7 +606,8 @@ static int send_stream_end(struct client *c)
 	size_t size;
 	char *mem;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "stream/end");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -610,10 +617,10 @@ static int send_stream_end(struct client *c)
 	spa_json_builder_pop(&b,             "]");
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 	return res;
 }
 #endif
@@ -623,10 +630,11 @@ static int send_group_update(struct client *c, bool playing)
 	struct impl *impl = c->impl;
 	struct spa_json_builder b;
 	int res;
-	char *mem;
+	spa_autofree char *mem = NULL;
 	size_t size;
 
-	spa_json_builder_memstream(&b, &mem, &size, 0);
+	if ((res = spa_json_builder_memstream(&b, &mem, &size, 0)) < 0)
+		return res;
 	spa_json_builder_array_push(&b,  "{");
 	spa_json_builder_object_string(&b, "type", "group/update");
 	spa_json_builder_object_push(&b,   "payload", "{");
@@ -635,13 +643,12 @@ static int send_group_update(struct client *c, bool playing)
 	spa_json_builder_object_string(&b,   "group_name", pw_properties_get(impl->props, "sendspin.group-name"));
 	spa_json_builder_pop(&b,           "}");
 	spa_json_builder_pop(&b,         "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		return res;
 
 	c->playing = playing;
 
-	res = pw_websocket_connection_send_text(c->conn, mem, size);
-	free(mem);
-	return res;
+	return pw_websocket_connection_send_text(c->conn, mem, size);
 }
 
 /* {"codec":"pcm","sample_rate":44100,"channels":2,"bit_depth":16} */
diff --git a/src/modules/module-snapcast-discover.c b/src/modules/module-snapcast-discover.c
index cb13371e1..c4e559a1e 100644
--- a/src/modules/module-snapcast-discover.c
+++ b/src/modules/module-snapcast-discover.c
@@ -19,6 +19,7 @@
 #include <net/if.h>
 #include <ifaddrs.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/utils/string.h>
 #include <spa/utils/json-builder.h>
@@ -533,7 +534,7 @@ static int create_stream(struct impl *impl, struct pw_properties *props,
 		struct tunnel *t)
 {
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	int res = 0;
 	struct pw_impl_module *mod;
@@ -567,13 +568,13 @@ static int create_stream(struct impl *impl, struct pw_properties *props,
 	spa_json_builder_array_push(&b, "{");
 	pw_properties_serialize_dict(b.f, &props->dict, 0);
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto done;
 
 	pw_log_info("loading module args:'%s'", args);
 	mod = pw_context_load_module(impl->context,
 			"libpipewire-module-protocol-simple",
 			args, NULL);
-	free(args);
 
 	if (mod == NULL) {
 		res = -errno;
diff --git a/src/modules/module-zeroconf-discover.c b/src/modules/module-zeroconf-discover.c
index f6f19192a..ddda1c3d8 100644
--- a/src/modules/module-zeroconf-discover.c
+++ b/src/modules/module-zeroconf-discover.c
@@ -12,6 +12,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/utils/string.h>
 #include <spa/utils/json-builder.h>
@@ -243,7 +244,7 @@ static void on_zeroconf_added(void *data, const void *user_data, const struct sp
 	struct tunnel_info tinfo;
 	const struct spa_dict_item *it;
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	struct pw_impl_module *mod;
 	struct pw_properties *props = NULL;
@@ -337,13 +338,13 @@ static void on_zeroconf_added(void *data, const void *user_data, const struct sp
 	spa_json_builder_object_push(&b,  "stream.props", "{");
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if (spa_json_builder_close(&b) < 0)
+		goto done;
 
 	pw_log_info("loading module args:'%s'", args);
 	mod = pw_context_load_module(impl->context,
 			"libpipewire-module-pulse-tunnel",
 			args, NULL);
-	free(args);
 
 	if (mod == NULL) {
 		pw_log_error("Can't load module: %m");
diff --git a/src/tools/pw-loopback.c b/src/tools/pw-loopback.c
index 3375beae4..6c01967b5 100644
--- a/src/tools/pw-loopback.c
+++ b/src/tools/pw-loopback.c
@@ -11,6 +11,7 @@
 #include <math.h>
 #include <locale.h>
 
+#include <spa/utils/cleanup.h>
 #include <spa/utils/result.h>
 #include <spa/pod/builder.h>
 #include <spa/param/audio/format-utils.h>
@@ -94,7 +95,7 @@ int main(int argc, char *argv[])
 	const char *opt_remote = NULL, *remote_name;
 	char cname[256];
 	struct spa_json_builder b;
-	char *args;
+	spa_autofree char *args = NULL;
 	size_t size;
 	static const struct option long_options[] = {
 		{ "help",		no_argument,		NULL, 'h' },
@@ -251,14 +252,14 @@ int main(int argc, char *argv[])
 	pw_properties_serialize_dict(b.f, &data.playback_props->dict, 0);
 	spa_json_builder_pop(&b,          "}");
 	spa_json_builder_pop(&b,        "}");
-	spa_json_builder_close(&b);
+	if ((res = spa_json_builder_close(&b)) < 0)
+		goto exit;
 
 	pw_log_info("loading module with %s", args);
 
 	data.module = pw_context_load_module(data.context,
 			"libpipewire-module-loopback", args,
 			NULL);
-	free(args);
 
 	if (data.module == NULL) {
 		fprintf(stderr, "can't load module: %m\n");