`RewindBlockIndex` reads `chainActive` (via `ChainActive()`) without holding `cs_main`:

https://github.com/bitcoin/bitcoin/blob/b2a6b0216192b6e8428f1a80b47f5178fccb961a/src/validation.cpp#L4314-L4331

(Please note that callers of `RewindBlockIndex` are _not_ allowed to hold `cs_main` since `RewindBlockIndex` indirectly calls `LimitValidationInterfaceQueue`.)
{
    AssertLockHeld(cs_main);
    std::vector<uint256> vHashUpdate;
    
    
    
    
    
    
    auto it = disconnectpool.queuedTx.get<insertion_order>().rbegin();
    while (it != disconnectpool.queuedTx.get<insertion_order>().rend()) {
        
        CValidationState stateDummy;
        if (!fAddToMempool || (*it)->IsCoinBase() ||