Add wtf log for the case that should not happen

Bug: 243314552
Test: atest BpfNetMapsTest
Change-Id: I8e97c8150d0f427b7b0ac26374322e36b013320a
diff --git a/service/src/com/android/server/BpfNetMaps.java b/service/src/com/android/server/BpfNetMaps.java
index 7387483..839cd16 100644
--- a/service/src/com/android/server/BpfNetMaps.java
+++ b/service/src/com/android/server/BpfNetMaps.java
@@ -545,9 +545,11 @@
                 synchronized (sUidOwnerMap) {
                     sUidOwnerMap.forEach((uid, config) -> {
                         // config could be null if there is a concurrent entry deletion.
-                        // http://b/220084230.
-                        if (config != null
-                                && !uidSet.contains((int) uid.val) && (config.rule & match) != 0) {
+                        // http://b/220084230. But sUidOwnerMap update must be done while holding a
+                        // lock, so this should not happen.
+                        if (config == null) {
+                            Log.wtf(TAG, "sUidOwnerMap entry was deleted while holding a lock");
+                        } else if (!uidSet.contains((int) uid.val) && (config.rule & match) != 0) {
                             uidSetToRemoveRule.add((int) uid.val);
                         }
                     });