all: avoid using global string buffer for to-string methods

These string functions allow to omit the string buffer. This is for
convenience, to use a global (thread-local) buffer. I think that is
error prone and we should drop that "convenience" feature.

At various places, pass a stack allocated buffer.

(cherry picked from commit b87afac8e8b8fe93a07da9eb6cc69bc0673b67bb)

8 files changed, 118 insertions, 62 deletions

diff --git a/src/core/dhcp/nm-dhcp-utils.c b/src/core/dhcp/nm-dhcp-utils.c
index 858516d0ea..a0eec6e099 100644
--- a/src/core/dhcp/nm-dhcp-utils.c
+++ b/src/core/dhcp/nm-dhcp-utils.c
@@ -300,6 +300,7 @@ process_classful_routes(const char     *iface,
     }
 
     for (s = searches; *s; s += 2) {
+        char               sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
         NMPlatformIP4Route route;
         guint32            rt_addr, rt_route;
 
@@ -342,7 +343,7 @@ process_classful_routes(const char     *iface,
         _LOG2I(LOGD_DHCP,
                iface,
                "  static route %s",
-               nm_platform_ip4_route_to_string(&route, NULL, 0));
+               nm_platform_ip4_route_to_string(&route, sbuf, sizeof(sbuf)));
     }
 }
 
diff --git a/src/core/dnsmasq/nm-dnsmasq-manager.c b/src/core/dnsmasq/nm-dnsmasq-manager.c
index c272a743af..be463da3e8 100644
--- a/src/core/dnsmasq/nm-dnsmasq-manager.c
+++ b/src/core/dnsmasq/nm-dnsmasq-manager.c
@@ -67,9 +67,12 @@ dm_watch_cb(GPid pid, int status, gpointer user_data)
     guint                    err;
 
     if (WIFEXITED(status)) {
+        char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
         err = WEXITSTATUS(status);
         if (err != 0) {
-            _LOGW("dnsmasq exited with error: %s", nm_utils_dnsmasq_status_to_string(err, NULL, 0));
+            _LOGW("dnsmasq exited with error: %s",
+                  nm_utils_dnsmasq_status_to_string(err, sbuf, sizeof(sbuf)));
         }
     } else if (WIFSTOPPED(status)) {
         _LOGW("dnsmasq stopped unexpectedly with signal %d", WSTOPSIG(status));
diff --git a/src/core/nm-config.c b/src/core/nm-config.c
index 60a2f1df53..ea1c2ab300 100644
--- a/src/core/nm-config.c
+++ b/src/core/nm-config.c
@@ -2870,6 +2870,7 @@ _set_config_data(NMConfig *self, NMConfigData *new_data, NMConfigChangeFlags rel
     NMConfigData       *old_data = priv->config_data;
     NMConfigChangeFlags changes, changes_diff;
     gboolean            had_new_data = !!new_data;
+    char                sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
 
     nm_assert(reload_flags);
     nm_assert(!NM_FLAGS_ANY(reload_flags, ~NM_CONFIG_CHANGE_CAUSES));
@@ -2901,15 +2902,15 @@ _set_config_data(NMConfig *self, NMConfigData *new_data, NMConfigChangeFlags rel
 
     if (new_data) {
         _LOGI("signal: %s (%s)",
-              nm_config_change_flags_to_string(changes, NULL, 0),
+              nm_config_change_flags_to_string(changes, sbuf, sizeof(sbuf)),
               nm_config_data_get_config_description(new_data));
         nm_config_data_log(new_data, "CONFIG: ", "  ", priv->no_auto_default_file, NULL);
         priv->config_data = new_data;
     } else if (had_new_data)
         _LOGI("signal: %s (no changes from disk)",
-              nm_config_change_flags_to_string(changes, NULL, 0));
+              nm_config_change_flags_to_string(changes, sbuf, sizeof(sbuf)));
     else
-        _LOGI("signal: %s", nm_config_change_flags_to_string(changes, NULL, 0));
+        _LOGI("signal: %s", nm_config_change_flags_to_string(changes, sbuf, sizeof(sbuf)));
     g_signal_emit(self, signals[SIGNAL_CONFIG_CHANGED], 0, new_data ?: old_data, changes, old_data);
     if (new_data)
         g_object_unref(old_data);
diff --git a/src/core/nm-test-utils-core.h b/src/core/nm-test-utils-core.h
index c036e94bae..467f9bb272 100644
--- a/src/core/nm-test-utils-core.h
+++ b/src/core/nm-test-utils-core.h
@@ -211,12 +211,13 @@ nmtst_platform_ip4_routes_equal(const NMPlatformIP4Route *a,
 
     for (i = 0; i < len; i++) {
         if (nm_platform_ip4_route_cmp_full(&a[i], &b[i]) != 0) {
-            char buf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+            char buf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
+            char buf2[NM_UTILS_TO_STRING_BUFFER_SIZE];
 
             g_error("Error comparing IPv4 route[%lu]: %s vs %s",
                     (unsigned long) i,
-                    nm_platform_ip4_route_to_string(&a[i], NULL, 0),
-                    nm_platform_ip4_route_to_string(&b[i], buf, sizeof(buf)));
+                    nm_platform_ip4_route_to_string(&a[i], buf1, sizeof(buf1)),
+                    nm_platform_ip4_route_to_string(&b[i], buf2, sizeof(buf2)));
             g_assert_not_reached();
         }
     }
@@ -280,12 +281,13 @@ nmtst_platform_ip6_routes_equal(const NMPlatformIP6Route *a,
 
     for (i = 0; i < len; i++) {
         if (nm_platform_ip6_route_cmp_full(&a[i], &b[i]) != 0) {
-            char buf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+            char buf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
+            char buf2[NM_UTILS_TO_STRING_BUFFER_SIZE];
 
             g_error("Error comparing IPv6 route[%lu]: %s vs %s",
                     (unsigned long) i,
-                    nm_platform_ip6_route_to_string(&a[i], NULL, 0),
-                    nm_platform_ip6_route_to_string(&b[i], buf, sizeof(buf)));
+                    nm_platform_ip6_route_to_string(&a[i], buf1, sizeof(buf1)),
+                    nm_platform_ip6_route_to_string(&b[i], buf2, sizeof(buf2)));
             g_assert_not_reached();
         }
     }
diff --git a/src/core/platform/tests/test-route.c b/src/core/platform/tests/test-route.c
index e39b17e2cb..2d39cb3789 100644
--- a/src/core/platform/tests/test-route.c
+++ b/src/core/platform/tests/test-route.c
@@ -1535,6 +1535,7 @@ _rule_fuzzy_equal(const NMPObject *obj, const NMPObject *obj_comp, int op_type)
 static void
 test_rule(gconstpointer test_data)
 {
+    char                         sbuf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
     const int                    TEST_IDX     = GPOINTER_TO_INT(test_data);
     const gboolean               TEST_SYNC    = (TEST_IDX == 4);
     gs_unref_ptrarray GPtrArray *objs         = NULL;
@@ -1763,7 +1764,7 @@ again:
 
                 g_print(">>> failing... errno=%d, rule=%s\n",
                         r,
-                        nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, NULL, 0));
+                        nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, sbuf1, sizeof(sbuf1)));
 
                 nmp_lookup_init_obj_type(&lookup, NMP_OBJECT_TYPE_ROUTING_RULE);
                 head_entry = nm_platform_lookup(platform, &lookup);
@@ -1775,9 +1776,10 @@ again:
                         && NMP_OBJECT_CAST_ROUTING_RULE(o)->priority
                                == NMP_OBJECT_CAST_ROUTING_RULE(obj)->priority)
                         ch = '*';
-                    g_print(">>> existing rule: %c %s\n",
-                            ch,
-                            nmp_object_to_string(o, NMP_OBJECT_TO_STRING_ALL, NULL, 0));
+                    g_print(
+                        ">>> existing rule: %c %s\n",
+                        ch,
+                        nmp_object_to_string(o, NMP_OBJECT_TO_STRING_ALL, sbuf1, sizeof(sbuf1)));
                 }
 
                 nmtstp_run_command_check("ip rule");
@@ -1836,11 +1838,14 @@ again:
 
                 if (!_rule_fuzzy_equal(obj, objs->pdata[k], RTM_DELRULE)) {
                     g_print(">>> failing...\n");
-                    g_print(">>> no fuzzy match between: %s\n",
-                            nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, NULL, 0));
                     g_print(
-                        ">>>                    and: %s\n",
-                        nmp_object_to_string(objs->pdata[k], NMP_OBJECT_TO_STRING_ALL, NULL, 0));
+                        ">>> no fuzzy match between: %s\n",
+                        nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, sbuf1, sizeof(sbuf1)));
+                    g_print(">>>                    and: %s\n",
+                            nmp_object_to_string(objs->pdata[k],
+                                                 NMP_OBJECT_TO_STRING_ALL,
+                                                 sbuf1,
+                                                 sizeof(sbuf1)));
                     g_assert_not_reached();
                 }
 
diff --git a/src/libnm-platform/nm-linux-platform.c b/src/libnm-platform/nm-linux-platform.c
index 6727294a65..40cb439692 100644
--- a/src/libnm-platform/nm-linux-platform.c
+++ b/src/libnm-platform/nm-linux-platform.c
@@ -6342,6 +6342,7 @@ cache_prune_one_type(NMPlatform *platform, const NMPLookup *lookup)
 
     nm_dedup_multi_iter_init(&iter, nmp_cache_lookup(cache, lookup));
     while (nm_dedup_multi_iter_next(&iter)) {
+        char                     sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
         const NMDedupMultiEntry *main_entry;
 
         /* we only track the dirty flag for the OBJECT-TYPE index. That means,
@@ -6353,7 +6354,7 @@ cache_prune_one_type(NMPlatform *platform, const NMPLookup *lookup)
         obj = main_entry->obj;
 
         _LOGt("cache-prune: prune %s",
-              nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, NULL, 0));
+              nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_ALL, sbuf, sizeof(sbuf)));
 
         {
             nm_auto_nmpobj const NMPObject *obj_old = NULL;
@@ -7026,6 +7027,7 @@ event_seq_check(NMPlatform             *platform,
 static void
 event_valid_msg(NMPlatform *platform, struct nl_msg *msg, gboolean handle_events)
 {
+    char                      sbuf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
     NMLinuxPlatformPrivate   *priv;
     nm_auto_nmpobj NMPObject *obj = NULL;
     NMPCacheOpsType           cache_op;
@@ -7082,8 +7084,8 @@ event_valid_msg(NMPlatform *platform, struct nl_msg *msg, gboolean handle_events
           is_dump ? ", in-dump" : "",
           nmp_object_to_string(obj,
                                is_del ? NMP_OBJECT_TO_STRING_ID : NMP_OBJECT_TO_STRING_PUBLIC,
-                               NULL,
-                               0));
+                               sbuf1,
+                               sizeof(sbuf1)));
 
     while (TRUE) {
         nm_auto_nmpobj const NMPObject *obj_old = NULL;
@@ -7309,6 +7311,7 @@ do_add_addrroute(NMPlatform      *platform,
                  struct nl_msg   *nlmsg,
                  gboolean         suppress_netlink_failure)
 {
+    char                    sbuf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
     WaitForNlResponseResult seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
     gs_free char           *errmsg     = NULL;
     int                     nle;
@@ -7331,7 +7334,7 @@ do_add_addrroute(NMPlatform      *platform,
     if (nle < 0) {
         _LOGE("do-add-%s[%s]: failure sending netlink request \"%s\" (%d)",
               NMP_OBJECT_GET_CLASS(obj_id)->obj_type_name,
-              nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
+              nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, sbuf1, sizeof(sbuf1)),
               nm_strerror(nle),
               -nle);
         return -NME_PL_NETLINK;
@@ -7347,7 +7350,7 @@ do_add_addrroute(NMPlatform      *platform,
                : LOGL_WARN,
            "do-add-%s[%s]: %s",
            NMP_OBJECT_GET_CLASS(obj_id)->obj_type_name,
-           nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
+           nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, sbuf1, sizeof(sbuf1)),
            wait_for_nl_response_to_string(seq_result, errmsg, s_buf, sizeof(s_buf)));
 
     if (NMP_OBJECT_GET_TYPE(obj_id) == NMP_OBJECT_TYPE_IP6_ADDRESS) {
@@ -7368,6 +7371,7 @@ do_add_addrroute(NMPlatform      *platform,
 static gboolean
 do_delete_object(NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *nlmsg)
 {
+    char                    sbuf1[NM_UTILS_TO_STRING_BUFFER_SIZE];
     WaitForNlResponseResult seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
     gs_free char           *errmsg     = NULL;
     int                     nle;
@@ -7386,7 +7390,7 @@ do_delete_object(NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *n
     if (nle < 0) {
         _LOGE("do-delete-%s[%s]: failure sending netlink request \"%s\" (%d)",
               NMP_OBJECT_GET_CLASS(obj_id)->obj_type_name,
-              nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
+              nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, sbuf1, sizeof(sbuf1)),
               nm_strerror(nle),
               -nle);
         return FALSE;
@@ -7418,7 +7422,7 @@ do_delete_object(NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *n
     _NMLOG(success ? LOGL_DEBUG : LOGL_WARN,
            "do-delete-%s[%s]: %s%s",
            NMP_OBJECT_GET_CLASS(obj_id)->obj_type_name,
-           nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
+           nmp_object_to_string(obj_id, NMP_OBJECT_TO_STRING_ID, sbuf1, sizeof(sbuf1)),
            wait_for_nl_response_to_string(seq_result, errmsg, s_buf, sizeof(s_buf)),
            log_detail);
 
diff --git a/src/libnm-platform/nm-platform.c b/src/libnm-platform/nm-platform.c
index cfaea6fc65..4fad8e6ae4 100644
--- a/src/libnm-platform/nm-platform.c
+++ b/src/libnm-platform/nm-platform.c
@@ -1875,9 +1875,10 @@ nm_platform_link_set_sriov_vfs(NMPlatform *self, int ifindex, const NMPlatformVF
 
     _LOG3D("link: setting VFs");
     for (i = 0; vfs[i]; i++) {
+        char                sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
         const NMPlatformVF *vf = vfs[i];
 
-        _LOG3D("link:   VF %s", nm_platform_vf_to_string(vf, NULL, 0));
+        _LOG3D("link:   VF %s", nm_platform_vf_to_string(vf, sbuf, sizeof(sbuf)));
     }
 
     return klass->link_set_sriov_vfs(self, ifindex, vfs);
@@ -1899,9 +1900,11 @@ nm_platform_link_set_bridge_vlans(NMPlatform                        *self,
            on_master ? "master" : "self");
     if (vlans) {
         for (i = 0; vlans[i]; i++) {
+            char                        sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
             const NMPlatformBridgeVlan *vlan = vlans[i];
 
-            _LOG3D("link:   bridge VLAN %s", nm_platform_bridge_vlan_to_string(vlan, NULL, 0));
+            _LOG3D("link:   bridge VLAN %s",
+                   nm_platform_bridge_vlan_to_string(vlan, sbuf, sizeof(sbuf)));
         }
     }
 
@@ -3543,6 +3546,7 @@ nm_platform_ip4_address_add(NMPlatform *self,
                          FALSE);
 
     if (_LOGD_ENABLED()) {
+        char                 sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
         NMPlatformIP4Address addr;
 
         addr = (NMPlatformIP4Address){
@@ -3561,7 +3565,7 @@ nm_platform_ip4_address_add(NMPlatform *self,
             g_strlcpy(addr.label, label, sizeof(addr.label));
 
         _LOG3D("address: adding or updating IPv4 address: %s",
-               nm_platform_ip4_address_to_string(&addr, NULL, 0));
+               nm_platform_ip4_address_to_string(&addr, sbuf, sizeof(sbuf)));
     }
     return klass->ip4_address_add(self,
                                   ifindex,
@@ -3593,6 +3597,7 @@ nm_platform_ip6_address_add(NMPlatform     *self,
     g_return_val_if_fail(preferred <= lifetime, FALSE);
 
     if (_LOGD_ENABLED()) {
+        char                 sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
         NMPlatformIP6Address addr = {0};
 
         addr.ifindex      = ifindex;
@@ -3605,7 +3610,7 @@ nm_platform_ip6_address_add(NMPlatform     *self,
         addr.n_ifa_flags  = flags;
 
         _LOG3D("address: adding or updating IPv6 address: %s",
-               nm_platform_ip6_address_to_string(&addr, NULL, 0));
+               nm_platform_ip6_address_to_string(&addr, sbuf, sizeof(sbuf)));
     }
     return klass
         ->ip6_address_add(self, ifindex, address, plen, peer_address, lifetime, preferred, flags);
@@ -5126,7 +5131,8 @@ nm_platform_ip6_route_add(NMPlatform *self, NMPNlmFlags flags, const NMPlatformI
 gboolean
 nm_platform_object_delete(NMPlatform *self, const NMPObject *obj)
 {
-    int ifindex;
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    int  ifindex;
 
     _CHECK_SELF(self, klass, FALSE);
 
@@ -5134,7 +5140,7 @@ nm_platform_object_delete(NMPlatform *self, const NMPObject *obj)
     case NMP_OBJECT_TYPE_ROUTING_RULE:
         _LOGD("%s: delete %s",
               NMP_OBJECT_GET_CLASS(obj)->obj_type_name,
-              nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+              nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
         break;
     case NMP_OBJECT_TYPE_IP4_ROUTE:
     case NMP_OBJECT_TYPE_IP6_ROUTE:
@@ -5143,7 +5149,7 @@ nm_platform_object_delete(NMPlatform *self, const NMPObject *obj)
         ifindex = NMP_OBJECT_CAST_OBJ_WITH_IFINDEX(obj)->ifindex;
         _LOG3D("%s: delete %s",
                NMP_OBJECT_GET_CLASS(obj)->obj_type_name,
-               nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+               nmp_object_to_string(obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
         break;
     default:
         g_return_val_if_reached(FALSE);
@@ -5161,6 +5167,7 @@ nm_platform_ip_route_get(NMPlatform   *self,
                          int           oif_ifindex,
                          NMPObject   **out_route)
 {
+    char                      sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     nm_auto_nmpobj NMPObject *route = NULL;
     int                       result;
     char                      buf[NM_UTILS_INET_ADDRSTRLEN];
@@ -5197,7 +5204,7 @@ nm_platform_ip_route_get(NMPlatform   *self,
         _LOGD("route: get IPv%c route for: %s succeeded: %s",
               nm_utils_addr_family_to_char(addr_family),
               inet_ntop(addr_family, address, buf, sizeof(buf)),
-              nmp_object_to_string(route, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+              nmp_object_to_string(route, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
         NM_SET_OUT(out_route, g_steal_pointer(&route));
     }
     return result;
@@ -5224,6 +5231,7 @@ _ip4_dev_route_blacklist_timeout_ms_marked(gint64 timeout_msec)
 static gboolean
 _ip4_dev_route_blacklist_check_cb(gpointer user_data)
 {
+    char               sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     NMPlatform        *self = user_data;
     NMPlatformPrivate *priv = NM_PLATFORM_GET_PRIVATE(self);
     GHashTableIter     iter;
@@ -5254,7 +5262,7 @@ again:
             continue;
 
         _LOGT("ip4-dev-route: delete %s",
-              nmp_object_to_string(p_obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+              nmp_object_to_string(p_obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
         nm_platform_object_delete(self, p_obj);
         goto again;
     }
@@ -5317,6 +5325,7 @@ _ip4_dev_route_blacklist_notify_route(NMPlatform *self, const NMPObject *obj)
 static gboolean
 _ip4_dev_route_blacklist_gc_timeout_handle(gpointer user_data)
 {
+    char               sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     NMPlatform        *self = user_data;
     NMPlatformPrivate *priv = NM_PLATFORM_GET_PRIVATE(self);
     GHashTableIter     iter;
@@ -5332,7 +5341,7 @@ _ip4_dev_route_blacklist_gc_timeout_handle(gpointer user_data)
     while (g_hash_table_iter_next(&iter, (gpointer *) &p_obj, (gpointer *) &p_timeout_ms)) {
         if (now_ms > _ip4_dev_route_blacklist_timeout_ms_get(*p_timeout_ms)) {
             _LOGT("ip4-dev-route: cleanup %s",
-                  nmp_object_to_string(p_obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+                  nmp_object_to_string(p_obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
             g_hash_table_iter_remove(&iter);
         }
     }
@@ -5392,6 +5401,7 @@ nm_platform_ip4_dev_route_blacklist_set(NMPlatform *self,
                                         int         ifindex,
                                         GPtrArray  *ip4_dev_route_blacklist)
 {
+    char               sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     NMPlatformPrivate *priv;
     GHashTableIter     iter;
     const NMPObject   *p_obj;
@@ -5447,14 +5457,17 @@ nm_platform_ip4_dev_route_blacklist_set(NMPlatform *self,
                 if (nmp_object_equal(p_obj, o)) {
                     /* un-expire and reuse the entry. */
                     _LOGT("ip4-dev-route: register %s (update)",
-                          nmp_object_to_string(p_obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+                          nmp_object_to_string(p_obj,
+                                               NMP_OBJECT_TO_STRING_PUBLIC,
+                                               sbuf,
+                                               sizeof(sbuf)));
                     *p_timeout_ms = timeout_msec_val;
                     continue;
                 }
             }
 
             _LOGT("ip4-dev-route: register %s",
-                  nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+                  nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
             p_timeout_ms  = g_slice_new(gint64);
             *p_timeout_ms = timeout_msec_val;
             g_hash_table_replace(priv->ip4_dev_route_blacklist_hash,
@@ -5476,12 +5489,13 @@ nm_platform_routing_rule_add(NMPlatform                  *self,
                              NMPNlmFlags                  flags,
                              const NMPlatformRoutingRule *routing_rule)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     _CHECK_SELF(self, klass, -NME_BUG);
 
     g_return_val_if_fail(routing_rule, -NME_BUG);
 
     _LOGD("routing-rule: adding or updating: %s",
-          nm_platform_routing_rule_to_string(routing_rule, NULL, 0));
+          nm_platform_routing_rule_to_string(routing_rule, sbuf, sizeof(sbuf)));
     return klass->routing_rule_add(self, flags, routing_rule);
 }
 
@@ -5490,13 +5504,15 @@ nm_platform_routing_rule_add(NMPlatform                  *self,
 int
 nm_platform_qdisc_add(NMPlatform *self, NMPNlmFlags flags, const NMPlatformQdisc *qdisc)
 {
-    int ifindex = qdisc->ifindex;
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    int  ifindex = qdisc->ifindex;
     _CHECK_SELF(self, klass, -NME_BUG);
 
     /* Note: @qdisc must not be copied or kept alive because the lifetime of qdisc.kind
      * is undefined. */
 
-    _LOG3D("adding or updating a qdisc: %s", nm_platform_qdisc_to_string(qdisc, NULL, 0));
+    _LOG3D("adding or updating a qdisc: %s",
+           nm_platform_qdisc_to_string(qdisc, sbuf, sizeof(sbuf)));
     return klass->qdisc_add(self, flags, qdisc);
 }
 
@@ -5514,13 +5530,15 @@ nm_platform_qdisc_delete(NMPlatform *self, int ifindex, guint32 parent, gboolean
 int
 nm_platform_tfilter_add(NMPlatform *self, NMPNlmFlags flags, const NMPlatformTfilter *tfilter)
 {
-    int ifindex = tfilter->ifindex;
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+    int  ifindex = tfilter->ifindex;
     _CHECK_SELF(self, klass, -NME_BUG);
 
     /* Note: @tfilter must not be copied or kept alive because the lifetime of tfilter.kind
      * and tfilter.action.kind is undefined. */
 
-    _LOG3D("adding or updating a tfilter: %s", nm_platform_tfilter_to_string(tfilter, NULL, 0));
+    _LOG3D("adding or updating a tfilter: %s",
+           nm_platform_tfilter_to_string(tfilter, sbuf, sizeof(sbuf)));
     return klass->tfilter_add(self, flags, tfilter);
 }
 
@@ -8927,9 +8945,11 @@ log_link(NMPlatform                *self,
          NMPlatformSignalChangeType change_type,
          gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: link %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_link_to_string(device, NULL, 0));
+           nm_platform_link_to_string(device, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -8940,9 +8960,11 @@ log_ip4_address(NMPlatform                *self,
                 NMPlatformSignalChangeType change_type,
                 gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: address 4 %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_ip4_address_to_string(address, NULL, 0));
+           nm_platform_ip4_address_to_string(address, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -8953,9 +8975,11 @@ log_ip6_address(NMPlatform                *self,
                 NMPlatformSignalChangeType change_type,
                 gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: address 6 %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_ip6_address_to_string(address, NULL, 0));
+           nm_platform_ip6_address_to_string(address, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -8966,9 +8990,11 @@ log_ip4_route(NMPlatform                *self,
               NMPlatformSignalChangeType change_type,
               gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: route   4 %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_ip4_route_to_string(route, NULL, 0));
+           nm_platform_ip4_route_to_string(route, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -8979,9 +9005,11 @@ log_ip6_route(NMPlatform                *self,
               NMPlatformSignalChangeType change_type,
               gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: route   6 %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_ip6_route_to_string(route, NULL, 0));
+           nm_platform_ip6_route_to_string(route, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -8992,10 +9020,12 @@ log_routing_rule(NMPlatform                *self,
                  NMPlatformSignalChangeType change_type,
                  gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     /* routing rules don't have an ifindex. We probably should refactor the signals that are emitted for platform changes. */
     _LOG3D("signal: rt-rule %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_routing_rule_to_string(routing_rule, NULL, 0));
+           nm_platform_routing_rule_to_string(routing_rule, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -9006,9 +9036,11 @@ log_qdisc(NMPlatform                *self,
           NMPlatformSignalChangeType change_type,
           gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: qdisc %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_qdisc_to_string(qdisc, NULL, 0));
+           nm_platform_qdisc_to_string(qdisc, sbuf, sizeof(sbuf)));
 }
 
 static void
@@ -9019,9 +9051,11 @@ log_tfilter(NMPlatform                *self,
             NMPlatformSignalChangeType change_type,
             gpointer                   user_data)
 {
+    char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
     _LOG3D("signal: tfilter %7s: %s",
            nm_platform_signal_change_type_to_string(change_type),
-           nm_platform_tfilter_to_string(tfilter, NULL, 0));
+           nm_platform_tfilter_to_string(tfilter, sbuf, sizeof(sbuf)));
 }
 
 /*****************************************************************************/
@@ -9032,6 +9066,7 @@ nm_platform_cache_update_emit_signal(NMPlatform      *self,
                                      const NMPObject *obj_old,
                                      const NMPObject *obj_new)
 {
+    char             sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     gboolean         visible_new;
     gboolean         visible_old;
     const NMPObject *o;
@@ -9094,7 +9129,7 @@ nm_platform_cache_update_emit_signal(NMPlatform      *self,
     _LOG3t("emit signal %s %s: %s",
            klass->signal_type,
            nm_platform_signal_change_type_to_string((NMPlatformSignalChangeType) cache_op),
-           nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+           nmp_object_to_string(o, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
 
     nmp_object_ref(o);
     g_signal_emit(self,
diff --git a/src/libnm-platform/nmp-route-manager.c b/src/libnm-platform/nmp-route-manager.c
index c31c9806a5..842301b1bd 100644
--- a/src/libnm-platform/nmp-route-manager.c
+++ b/src/libnm-platform/nmp-route-manager.c
@@ -397,14 +397,17 @@ nmp_route_manager_track(NMPRouteManager *self,
     _track_data_assert(track_data, TRUE);
 
     if (changed) {
-        _LOGD("track [" NM_HASH_OBFUSCATE_PTR_FMT ",%s%u] %s \"%s\"",
-              NM_HASH_OBFUSCATE_PTR(track_data->user_tag),
-              (track_data->track_priority_val == 0
-                   ? ""
-                   : (track_data->track_priority_present ? "+" : "-")),
-              (guint) track_data->track_priority_val,
-              NMP_OBJECT_GET_CLASS(track_data->obj)->obj_type_name,
-              nmp_object_to_string(track_data->obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+        char sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
+
+        _LOGD(
+            "track [" NM_HASH_OBFUSCATE_PTR_FMT ",%s%u] %s \"%s\"",
+            NM_HASH_OBFUSCATE_PTR(track_data->user_tag),
+            (track_data->track_priority_val == 0
+                 ? ""
+                 : (track_data->track_priority_present ? "+" : "-")),
+            (guint) track_data->track_priority_val,
+            NMP_OBJECT_GET_CLASS(track_data->obj)->obj_type_name,
+            nmp_object_to_string(track_data->obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
     }
 
     return changed || changed_untrack;
@@ -416,6 +419,7 @@ _track_data_untrack(NMPRouteManager *self,
                     gboolean         remove_user_tag_data,
                     gboolean         make_owned_by_us)
 {
+    char          sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     TrackObjData *obj_data;
 
     nm_assert(NMP_IS_ROUTE_MANAGER(self));
@@ -426,7 +430,7 @@ _track_data_untrack(NMPRouteManager *self,
     _LOGD("untrack [" NM_HASH_OBFUSCATE_PTR_FMT "] %s \"%s\"",
           NM_HASH_OBFUSCATE_PTR(track_data->user_tag),
           NMP_OBJECT_GET_CLASS(track_data->obj)->obj_type_name,
-          nmp_object_to_string(track_data->obj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+          nmp_object_to_string(track_data->obj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
 
 #if NM_MORE_ASSERTS
     {
@@ -552,6 +556,7 @@ nmp_route_manager_untrack_all(NMPRouteManager *self,
 void
 nmp_route_manager_sync(NMPRouteManager *self, NMPObjectType obj_type, gboolean keep_deleted)
 {
+    char                         sbuf[NM_UTILS_TO_STRING_BUFFER_SIZE];
     const NMDedupMultiHeadEntry *pl_head_entry;
     NMDedupMultiIter             pl_iter;
     const NMPObject             *plobj;
@@ -608,7 +613,7 @@ nmp_route_manager_sync(NMPRouteManager *self, NMPObjectType obj_type, gboolean k
             if (keep_deleted) {
                 _LOGD("forget/leak object added by us: %s \"%s\"",
                       NMP_OBJECT_GET_CLASS(plobj)->obj_type_name,
-                      nmp_object_to_string(plobj, NMP_OBJECT_TO_STRING_PUBLIC, NULL, 0));
+                      nmp_object_to_string(plobj, NMP_OBJECT_TO_STRING_PUBLIC, sbuf, sizeof(sbuf)));
                 continue;
             }