`LockAnnotation lock(::cs_main)` is a guarantee to the compiler thread analysis that `::cs_main` is locked (when it couldn't be determined otherwise).

Despite being annotated with the locking guarantee ...

https://github.com/bitcoin/bitcoin/blob/65526fc8666fef35ef908dbc225f706bef642c7e/src/interfaces/chain.cpp#L134-L138

... `getTipLocator()` reads `chainActive` (via `::ChainActive()`) without holding `cs_main`.

This can be verified by adding the following `AssertLockHeld(cs_main)`:

```
$ git diff
diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index 59623284d..9fc693a0f 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -134,6 +134,7 @@ class LockImpl : public Chain::Lock
     CBlockLocator getTipLocator() override
     {
         LockAnnotation lock(::cs_main);
+        AssertLockHeld(::cs_main);
         return ::ChainActive().GetLocator();
     }
     Optional<int> findLocatorFork(const CBlockLocator& locator) override
$ make check
../build-aux/test-driver: line 107: 12881 Aborted                 "$@" > $log_file 2>&1
FAIL: qt/test/test_bitcoin-qt
```
CPubKey seed = walletInstance->GenerateNewSeed();
            walletInstance->SetHDSeed(seed);
        } 
        
        if (walletInstance->CanGenerateKeys() && !walletInstance->TopUpKeyPool()) {
            chain.initError(_("Unable to generate initial keys"));
            return nullptr;
        }
        auto locked_chain = chain.lock();
        walletInstance->ChainStateFlushed(locked_chain->getTipLocator());
    } else if (wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS) {
        
        chain.initError(strprintf(_("Error loading %s: Private keys can only be disabled during creation"), walletFile));
        return NULL;
    } else if (walletInstance->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        LOCK(walletInstance->cs_KeyStore);
        if (!walletInstance->mapKeys.empty() || !walletInstance->mapCryptedKeys.empty()) {
            chain.initWarning(strprintf(_("Warning: Private keys detected in wallet {%s} with disabled private keys"), walletFile));
        }
    }
    if (!gArgs.GetArg("-addresstype", "").empty() && !ParseOutputType(gArgs.GetArg("-addresstype", ""), walletInstance->m_default_address_type)) {
        chain.initError(strprintf("Unknown address type '%s'", gArgs.GetArg("-addresstype", "")));
        return nullptr;
    }
    if (!gArgs.GetArg("-changetype", "").empty() && !ParseOutputType(gArgs.GetArg("-changetype", ""), walletInstance->m_default_change_type)) {
        chain.initError(strprintf("Unknown change type '%s'", gArgs.GetArg("-changetype", "")));
        return nullptr;
    }
    if (gArgs.IsArgSet("-mintxfee")) {
        CAmount n = 0;