detect: avoid potential use-after-free in error path

src/detect-engine.c

@@ -2322,14 +2322,16 @@ TmEcode DetectEngineThreadCtxInit(ThreadVars *tv, void *initdata, void **data)
     det_ctx->counter_match_list = StatsRegisterAvgCounter("detect.match_list", tv);
 #endif
 
-    /* pass thread data back to caller */
-    *data = (void *)det_ctx;
-
     if (DetectEngineMultiTenantEnabled()) {
-        if (DetectEngineThreadCtxInitForMT(tv, det_ctx) != TM_ECODE_OK)
+        if (DetectEngineThreadCtxInitForMT(tv, det_ctx) != TM_ECODE_OK) {
+            DetectEngineThreadCtxDeinit(tv, det_ctx);
             return TM_ECODE_FAILED;
+        }
     }
 
+    /* pass thread data back to caller */
+    *data = (void *)det_ctx;
+
     return TM_ECODE_OK;
 }