Stop DM test event loops promptly on scenario failure

tests/test_dm_e2e.c

@@ -189,6 +189,7 @@ static void write_configs(const char* dir) {
 /* ── чистые проверки (без опроса) ── */
 
 static int conn_up(struct UTUN_INSTANCE* inst, uint64_t nid) {
+    if (!inst) return 0;
     struct ETCP_CONN* c = instance_find_conn(inst, nid);
     return c && c->initialized && c->links_up;
 }
@@ -517,12 +518,13 @@ static void dm_tick(void* arg) {
         return;
     }
 
+    if (t->result) { uasync_stop(t->ua); return; }
     if (t->phase == P_DONE) { t->result = 1; uasync_stop(t->ua); return; }
 
     if (++t->ticks > MAX_TICKS) {
         fprintf(stderr, "test: timeout in phase %d (A_conn=%d C_conn=%d B_conn=%d)\n",
                 (int)t->phase,
-                conn_up(A, nc), conn_up(C, na), B ? conn_up(B, nc) : -1);
+                conn_up(t->inst[IDX_A], nc), conn_up(t->inst[IDX_C], na), conn_up(t->inst[IDX_B], nc));
         t->result = 2;
         uasync_stop(t->ua);
         return;
@@ -635,12 +637,13 @@ static void dm2_tick(void* arg) {
         return;
     }
 
+    if (t->result) { uasync_stop(t->ua); return; }
     if (t->phase == S2_DONE) { t->result = 1; uasync_stop(t->ua); return; }
 
     if (++t->ticks > MAX_TICKS) {
         fprintf(stderr, "s2: timeout in phase %d (A_conn=%d C_conn=%d B_conn=%d)\n",
                 (int)t->phase,
-                conn_up(A, nc), conn_up(C, na), B ? conn_up(B, nc) : -1);
+                conn_up(t->inst[IDX_A], nc), conn_up(t->inst[IDX_C], na), conn_up(t->inst[IDX_B], nc));
         t->result = 2;
         uasync_stop(t->ua);
         return;