`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
```
{
    if (!CWallet::Verify(chain, location, false, error, warning)) {
        error = "Wallet file verification failed: " + error;
        return nullptr;
    }
    std::shared_ptr<CWallet> wallet = CWallet::CreateWalletFromFile(chain, location);
    if (!wallet) {
        error = "Wallet loading failed.";
        return nullptr;
    }
    AddWallet(wallet);
    wallet->postInitProcess();
    return wallet;
}
std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const std::string& name, std::string& error, std::string& warning)
{
    return LoadWallet(chain, WalletLocation(name), error, warning);
}
const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
const uint256 CMerkleTx::ABANDON_HASH(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
/** @defgroup mapWallet
 *
 * @{
 */
std::string COutput::ToString() const