[Bugfix] fix to use single wasmvm during recursive external query

CHANGELOG.md

@@ -1,3 +1,8 @@
+## [v0.5.9]
+
+### Bug Fixes
+- [\#588](https://github.com/terra-money/core/pull/588) - fix wasm external querier to use single wasmvm with context value
+
 ## [v0.5.8]
 
 ### Bug Fixes

x/wasm/keeper/contract.go

@@ -420,7 +420,7 @@ func (k Keeper) queryToStore(ctx sdk.Context, contractAddress sdk.AccAddress, ke
 	return prefixStore.Get(key)
 }
 
-func (k Keeper) queryToContract(ctx sdk.Context, contractAddress sdk.AccAddress, queryMsg []byte, wasmVMs ...types.WasmerEngine) ([]byte, error) {
+func (k Keeper) queryToContract(ctx sdk.Context, contractAddress sdk.AccAddress, queryMsg []byte) ([]byte, error) {
 	defer telemetry.MeasureSince(time.Now(), "wasm", "contract", "query-smart")
 	ctx.GasMeter().ConsumeGas(types.InstantiateContractCosts(len(queryMsg)), "Loading CosmWasm module: query")
 
@@ -432,9 +432,11 @@ func (k Keeper) queryToContract(ctx sdk.Context, contractAddress sdk.AccAddress,
 	env := types.NewEnv(ctx, contractAddress)
 
 	// when the vm is given, use that given vm
-	wasmVM := k.wasmVM
-	if len(wasmVMs) != 0 {
-		wasmVM = wasmVMs[0]
+	var wasmVM types.WasmerEngine
+	if vm := ctx.Context().Value(types.QueryWasmVMContextKey); vm != nil {
+		wasmVM = vm.(types.WasmerEngine)
+	} else {
+		wasmVM = k.wasmVM
 	}
 
 	// assert max depth to prevent stack overflow

x/wasm/keeper/keeper.go

@@ -35,7 +35,7 @@ type Keeper struct {
 	queryRouter   types.GRPCQueryRouter
 
 	wasmVM              types.WasmerEngine
-	wasmReadVMPool      []types.WasmerEngine
+	wasmReadVMPool      *[]types.WasmerEngine
 	wasmReadVMSemaphore *semaphore.Weighted
 	wasmReadVMMutex     *sync.Mutex
 
@@ -114,7 +114,7 @@ func NewKeeper(
 		cdc:                 cdc,
 		paramSpace:          paramspace,
 		wasmVM:              writeWasmVM,
-		wasmReadVMPool:      wasmReadVMPool,
+		wasmReadVMPool:      &wasmReadVMPool,
 		wasmReadVMSemaphore: semaphore.NewWeighted(int64(numReadVms)),
 		wasmReadVMMutex:     &sync.Mutex{},
 		accountKeeper:       accountKeeper,

x/wasm/keeper/legacy_querier.go

@@ -1,6 +1,7 @@
 package keeper
 
 import (
+	"context"
 	"fmt"
 	"runtime/debug"
 
@@ -147,7 +148,9 @@ func queryContractStore(ctx sdk.Context, req abci.RequestQuery, k Keeper, legacy
 		}
 	}()
 
-	bz, err = k.queryToContract(ctx, params.ContractAddress, params.Msg, wasmVM)
+	// store query wasmvm in the context
+	ctx = ctx.WithContext(context.WithValue(ctx.Context(), types.QueryWasmVMContextKey, wasmVM))
+	bz, err = k.queryToContract(ctx, params.ContractAddress, params.Msg)
 
 	return
 }

x/wasm/keeper/pool.go

@@ -6,25 +6,23 @@ import (
 	"github.com/terra-money/core/x/wasm/types"
 )
 
-var n = 0
-
 func (k Keeper) acquireWasmVM(ctx context.Context) (types.WasmerEngine, error) {
 	err := k.wasmReadVMSemaphore.Acquire(ctx, 1)
 	if err != nil {
 		return nil, err
 	}
 
 	k.wasmReadVMMutex.Lock()
-	wasmVM := k.wasmReadVMPool[0]
-	k.wasmReadVMPool = k.wasmReadVMPool[1:]
+	wasmVM := (*k.wasmReadVMPool)[0]
+	*k.wasmReadVMPool = (*k.wasmReadVMPool)[1:]
 	k.wasmReadVMMutex.Unlock()
 
 	return wasmVM, nil
 }
 
 func (k Keeper) releaseWasmVM(wasmVM types.WasmerEngine) {
 	k.wasmReadVMMutex.Lock()
-	k.wasmReadVMPool = append(k.wasmReadVMPool, wasmVM)
+	*k.wasmReadVMPool = append(*k.wasmReadVMPool, wasmVM)
 	k.wasmReadVMMutex.Unlock()
 
 	k.wasmReadVMSemaphore.Release(1)

x/wasm/keeper/querier.go

@@ -120,8 +120,9 @@ func (q querier) ContractStore(c context.Context, req *types.QueryContractStoreR
 		}
 	}()
 
-	var bz []byte
-	bz, err = q.queryToContract(ctx, contractAddr, req.QueryMsg, wasmVM)
+	// store query wasmvm in the context
+	ctx = ctx.WithContext(context.WithValue(ctx.Context(), types.QueryWasmVMContextKey, wasmVM))
+	bz, err := q.queryToContract(ctx, contractAddr, req.QueryMsg)
 	if err != nil {
 		return nil, status.Error(codes.Internal, err.Error())
 	}

x/wasm/keeper/recursive_test.go

@@ -1,6 +1,7 @@
 package keeper
 
 import (
+	"context"
 	"encoding/json"
 	"io/ioutil"
 	"testing"
@@ -344,18 +345,25 @@ func TestLimitRecursiveQueryGas(t *testing.T) {
 }
 
 func TestLimitRecursiveQueryDepth(t *testing.T) {
-
 	contractAddr, _, ctx, keeper, _ := initRecurseContract(t)
+	// pick query wasmvm
+	wasmvm, err := keeper.acquireWasmVM(ctx.Context())
+	require.NoError(t, err)
+	defer keeper.releaseWasmVM(wasmvm)
+
+	ctx = ctx.WithContext(context.WithValue(ctx.Context(), types.QueryWasmVMContextKey, wasmvm))
+
+	// exceed max query depth
 	msg := buildQuery(t, Recurse{
-		Depth: types.ContractMaxQueryDepth - 1, // need to include first query
+		Depth: types.ContractMaxQueryDepth,
 	})
 
-	_, err := keeper.queryToContract(ctx, contractAddr, msg)
-	require.NoError(t, err)
+	_, err = keeper.queryToContract(ctx, contractAddr, msg)
+	require.Error(t, err)
 
 	msg = buildQuery(t, Recurse{
-		Depth: types.ContractMaxQueryDepth,
+		Depth: types.ContractMaxQueryDepth - 1, // need to include first query
 	})
 	_, err = keeper.queryToContract(ctx, contractAddr, msg)
-	require.Error(t, err)
+	require.NoError(t, err)
 }

x/wasm/types/keys.go

@@ -20,6 +20,9 @@ const (
 
 	// RouterKey is the msg router key for the wasm module
 	RouterKey = ModuleName
+
+	// QueryWasmVMContextKey is the context key to store wasmvm in query context
+	QueryWasmVMContextKey = "wasmvm"
 )
 
 // Keys for wasm store