@kasey feedback round 2

beacon-chain/db/kv/archived_point.go

@@ -2,6 +2,7 @@ package kv
 
 import (
 	"context"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v7/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
@@ -33,6 +34,9 @@ func (s *Store) LastArchivedRoot(ctx context.Context) [32]byte {
 	if err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(stateSlotIndicesBucket)
 		_, blockRoot = bkt.Cursor().Last()
+		if len(blockRoot) > 0 {
+			blockRoot = slices.Clone(blockRoot)
+		}
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
 		panic(err) // lint:nopanic -- View never returns an error.
@@ -51,6 +55,9 @@ func (s *Store) ArchivedPointRoot(ctx context.Context, slot primitives.Slot) [32
 	if err := s.db.View(func(tx *bolt.Tx) error {
 		bucket := tx.Bucket(stateSlotIndicesBucket)
 		blockRoot = bucket.Get(bytesutil.SlotToBytesBigEndian(slot))
+		if len(blockRoot) > 0 {
+			blockRoot = slices.Clone(blockRoot)
+		}
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
 		panic(err) // lint:nopanic -- View never returns an error.

beacon-chain/db/kv/blocks.go

@@ -812,7 +812,10 @@ func (s *Store) FeeRecipientByValidatorID(ctx context.Context, id primitives.Val
 	var addr []byte
 	err := s.db.View(func(tx *bolt.Tx) error {
 		bkt := tx.Bucket(feeRecipientBucket)
-		addr = bkt.Get(bytesutil.Uint64ToBytesBigEndian(uint64(id)))
+		stored := bkt.Get(bytesutil.Uint64ToBytesBigEndian(uint64(id)))
+		if len(stored) > 0 {
+			addr = slices.Clone(stored)
+		}
 		// IF the fee recipient is not found in the standard fee recipient bucket, then
 		// check the registration bucket. The fee recipient may be there.
 		// This is to resolve imcompatility until we fully migrate to the registration bucket.
@@ -826,7 +829,7 @@ func (s *Store) FeeRecipientByValidatorID(ctx context.Context, id primitives.Val
 			if err := decode(ctx, enc, reg); err != nil {
 				return err
 			}
-			addr = reg.FeeRecipient
+			addr = slices.Clone(reg.FeeRecipient)
 		}
 		return nil
 	})

beacon-chain/db/kv/deposit_contract.go

@@ -3,6 +3,7 @@ package kv
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
 	"github.com/ethereum/go-ethereum/common"
@@ -17,7 +18,10 @@ func (s *Store) DepositContractAddress(ctx context.Context) ([]byte, error) {
 	var addr []byte
 	if err := s.db.View(func(tx *bolt.Tx) error {
 		chainInfo := tx.Bucket(chainMetadataBucket)
-		addr = chainInfo.Get(depositContractAddressKey)
+		stored := chainInfo.Get(depositContractAddressKey)
+		if len(stored) > 0 {
+			addr = slices.Clone(stored)
+		}
 		return nil
 	}); err != nil { // This view never returns an error, but we'll handle anyway for sanity.
 		panic(err) // lint:nopanic -- View never returns an error.

beacon-chain/db/kv/migration_state_validators.go

@@ -199,7 +199,7 @@ func performValidatorStateMigration(ctx context.Context, bar *progressbar.Progre
 func stateBucketKeys(stateBucket *bolt.Bucket) ([][]byte, error) {
 	var keys [][]byte
 	if err := stateBucket.ForEach(func(pubKey, v []byte) error {
-		keys = append(keys, pubKey)
+		keys = append(keys, bytes.Clone(pubKey))
 		return nil
 	}); err != nil {
 		return nil, err

beacon-chain/db/kv/state_diff.go

@@ -2,6 +2,7 @@ package kv
 
 import (
 	"context"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v7/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/flags"
@@ -187,20 +188,23 @@ func (s *Store) getDiff(lvl int, slot uint64) (hdiff.HdiffBytes, error) {
 			return bolt.ErrBucketNotFound
 		}
 		buf := append(key, stateSuffix...)
-		stateDiff = bucket.Get(buf)
-		if stateDiff == nil {
+		rawStateDiff := bucket.Get(buf)
+		if len(rawStateDiff) == 0 {
 			return errors.New("state diff not found")
 		}
+		stateDiff = slices.Clone(rawStateDiff)
 		buf = append(key, validatorSuffix...)
-		validatorDiff = bucket.Get(buf)
-		if validatorDiff == nil {
+		rawValidatorDiff := bucket.Get(buf)
+		if len(rawValidatorDiff) == 0 {
 			return errors.New("validator diff not found")
 		}
+		validatorDiff = slices.Clone(rawValidatorDiff)
 		buf = append(key, balancesSuffix...)
-		balancesDiff = bucket.Get(buf)
-		if balancesDiff == nil {
+		rawBalancesDiff := bucket.Get(buf)
+		if len(rawBalancesDiff) == 0 {
 			return errors.New("balances diff not found")
 		}
+		balancesDiff = slices.Clone(rawBalancesDiff)
 		return nil
 	})
 
@@ -224,10 +228,11 @@ func (s *Store) getFullSnapshot(slot uint64) (state.BeaconState, error) {
 		if bucket == nil {
 			return bolt.ErrBucketNotFound
 		}
-		enc = bucket.Get(key)
-		if enc == nil {
+		rawEnc := bucket.Get(key)
+		if rawEnc == nil {
 			return errors.New("state not found")
 		}
+		enc = slices.Clone(rawEnc)
 		return nil
 	})
 

beacon-chain/db/kv/state_summary.go

@@ -2,6 +2,7 @@ package kv
 
 import (
 	"context"
+	"slices"
 
 	"github.com/OffchainLabs/prysm/v7/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v7/monitoring/tracing/trace"
@@ -47,7 +48,11 @@ func (s *Store) StateSummary(ctx context.Context, blockRoot [32]byte) (*ethpb.St
 	}
 	var enc []byte
 	if err := s.db.View(func(tx *bolt.Tx) error {
-		enc = tx.Bucket(stateSummaryBucket).Get(blockRoot[:])
+		rawEnc := tx.Bucket(stateSummaryBucket).Get(blockRoot[:])
+		if len(rawEnc) == 0 {
+			return nil
+		}
+		enc = slices.Clone(rawEnc)
 		return nil
 	}); err != nil {
 		return nil, err

changelog/pvl-bbolt-read-copy.md

@@ -0,0 +1,3 @@
+### Fixed
+
+- Fixed some database slices that were used outside of a read transaction. See [bbolt README](https://github.com/etcd-io/bbolt/blob/7b38172caf8cde993d187be4b8738fbe9266fde8/README.md?plain=1#L852) for more on this caveat.