core: fix write concurrency in txpool (#19835)

* core: fix write coucurrency in txpool

* core: add rlock for pendingState read access

* core: address comments

core/tx_noncer.go

@@ -17,6 +17,8 @@
 package core
 
 import (
+	"sync"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/state"
 )
@@ -27,6 +29,7 @@ import (
 type txNoncer struct {
 	fallback *state.StateDB
 	nonces   map[common.Address]uint64
+	lock     sync.Mutex
 }
 
 // newTxNoncer creates a new virtual state database to track the pool nonces.
@@ -40,6 +43,11 @@ func newTxNoncer(statedb *state.StateDB) *txNoncer {
 // get returns the current nonce of an account, falling back to a real state
 // database if the account is unknown.
 func (txn *txNoncer) get(addr common.Address) uint64 {
+	// We use mutex for get operation is the underlying
+	// state will mutate db even for read access.
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
 	if _, ok := txn.nonces[addr]; !ok {
 		txn.nonces[addr] = txn.fallback.GetNonce(addr)
 	}
@@ -49,5 +57,23 @@ func (txn *txNoncer) get(addr common.Address) uint64 {
 // set inserts a new virtual nonce into the virtual state database to be returned
 // whenever the pool requests it instead of reaching into the real state database.
 func (txn *txNoncer) set(addr common.Address, nonce uint64) {
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	txn.nonces[addr] = nonce
+}
+
+// setIfLower updates a new virtual nonce into the virtual state database if the
+// the new one is lower.
+func (txn *txNoncer) setIfLower(addr common.Address, nonce uint64) {
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	if _, ok := txn.nonces[addr]; !ok {
+		txn.nonces[addr] = txn.fallback.GetNonce(addr)
+	}
+	if txn.nonces[addr] <= nonce {
+		return
+	}
 	txn.nonces[addr] = nonce
 }