diff --git a/cmd/tendermint/commands/gen_validator.go b/cmd/tendermint/commands/gen_validator.go
index 984176d2a..59fe30128 100644
--- a/cmd/tendermint/commands/gen_validator.go
+++ b/cmd/tendermint/commands/gen_validator.go
@@ -19,7 +19,10 @@ var GenValidatorCmd = &cobra.Command{
 
 func genValidator(cmd *cobra.Command, args []string) {
 	privValidator := types.GenPrivValidatorFS("")
-	privValidatorJSONBytes, _ := json.MarshalIndent(privValidator, "", "\t")
+	privValidatorJSONBytes, err := json.MarshalIndent(privValidator, "", "\t")
+	if err != nil {
+		panic(err)
+	}
 	fmt.Printf(`%v
 `, string(privValidatorJSONBytes))
 }
diff --git a/consensus/replay_file.go b/consensus/replay_file.go
index 4d5a631dc..ba7b12654 100644
--- a/consensus/replay_file.go
+++ b/consensus/replay_file.go
@@ -59,7 +59,7 @@ func (cs *ConsensusState) ReplayFile(file string, console bool) error {
 	defer cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
 
 	// just open the file for reading, no need to use wal
-	fp, err := os.OpenFile(file, os.O_RDONLY, 0666)
+	fp, err := os.OpenFile(file, os.O_RDONLY, 0600)
 	if err != nil {
 		return err
 	}
@@ -130,7 +130,7 @@ func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
 	if err := pb.fp.Close(); err != nil {
 		return err
 	}
-	fp, err := os.OpenFile(pb.fileName, os.O_RDONLY, 0666)
+	fp, err := os.OpenFile(pb.fileName, os.O_RDONLY, 0600)
 	if err != nil {
 		return err
 	}
diff --git a/node/node.go b/node/node.go
index 2de87b1ea..def313943 100644
--- a/node/node.go
+++ b/node/node.go
@@ -430,7 +430,10 @@ func (n *Node) startRPC() ([]net.Listener, error) {
 		mux := http.NewServeMux()
 		rpcLogger := n.Logger.With("module", "rpc-server")
 		onDisconnect := rpcserver.OnDisconnect(func(remoteAddr string) {
-			n.eventBus.UnsubscribeAll(context.Background(), remoteAddr)
+			err := n.eventBus.UnsubscribeAll(context.Background(), remoteAddr)
+			if err != nil {
+				rpcLogger.Error("Error unsubsribing from all on disconnect", "err", err)
+			}
 		})
 		wm := rpcserver.NewWebsocketManager(rpccore.Routes, onDisconnect)
 		wm.SetLogger(rpcLogger.With("protocol", "websocket"))
diff --git a/p2p/fuzz.go b/p2p/fuzz.go
index dfa34fa1d..fa16e4a26 100644
--- a/p2p/fuzz.go
+++ b/p2p/fuzz.go
@@ -124,7 +124,7 @@ func (fc *FuzzedConnection) SetWriteDeadline(t time.Time) error {
 
 func (fc *FuzzedConnection) randomDuration() time.Duration {
 	maxDelayMillis := int(fc.config.MaxDelay.Nanoseconds() / 1000)
-	return time.Millisecond * time.Duration(rand.Int()%maxDelayMillis)
+	return time.Millisecond * time.Duration(rand.Int()%maxDelayMillis) // nolint: gas
 }
 
 // implements the fuzz (delay, kill conn)
@@ -143,7 +143,7 @@ func (fc *FuzzedConnection) fuzz() bool {
 		} else if r < fc.config.ProbDropRW+fc.config.ProbDropConn {
 			// XXX: can't this fail because machine precision?
 			// XXX: do we need an error?
-			fc.Close() // nolint: errcheck
+			fc.Close() // nolint: errcheck, gas
 			return true
 		} else if r < fc.config.ProbDropRW+fc.config.ProbDropConn+fc.config.ProbSleep {
 			time.Sleep(fc.randomDuration())
diff --git a/p2p/pex_reactor.go b/p2p/pex_reactor.go
index 71c3beb0d..73bb9e75e 100644
--- a/p2p/pex_reactor.go
+++ b/p2p/pex_reactor.go
@@ -283,7 +283,7 @@ func (r *PEXReactor) ensurePeers() {
 	// If we need more addresses, pick a random peer and ask for more.
 	if r.book.NeedMoreAddrs() {
 		if peers := r.Switch.Peers().List(); len(peers) > 0 {
-			i := rand.Int() % len(peers)
+			i := rand.Int() % len(peers) // nolint: gas
 			peer := peers[i]
 			r.Logger.Info("No addresses to dial. Sending pexRequest to random peer", "peer", peer)
 			r.RequestPEX(peer)
diff --git a/p2p/secret_connection.go b/p2p/secret_connection.go
index 1e9bffc54..aec0a7519 100644
--- a/p2p/secret_connection.go
+++ b/p2p/secret_connection.go
@@ -302,7 +302,7 @@ func shareAuthSignature(sc *SecretConnection, pubKey crypto.PubKeyEd25519, signa
 // sha256
 func hash32(input []byte) (res *[32]byte) {
 	hasher := sha256.New()
-	hasher.Write(input) // nolint: errcheck
+	hasher.Write(input) // nolint: errcheck, gas
 	resSlice := hasher.Sum(nil)
 	res = new([32]byte)
 	copy(res[:], resSlice)
@@ -312,7 +312,7 @@ func hash32(input []byte) (res *[32]byte) {
 // We only fill in the first 20 bytes with ripemd160
 func hash24(input []byte) (res *[24]byte) {
 	hasher := ripemd160.New()
-	hasher.Write(input) // nolint: errcheck
+	hasher.Write(input) // nolint: errcheck, gas
 	resSlice := hasher.Sum(nil)
 	res = new([24]byte)
 	copy(res[:], resSlice)
diff --git a/p2p/trust/trustmetric.go b/p2p/trust/trustmetric.go
index cbc2db7d5..c6740c0da 100644
--- a/p2p/trust/trustmetric.go
+++ b/p2p/trust/trustmetric.go
@@ -47,7 +47,9 @@ func NewTrustMetricStore(db dbm.DB, tmc TrustMetricConfig) *TrustMetricStore {
 
 // OnStart implements Service
 func (tms *TrustMetricStore) OnStart() error {
-	tms.BaseService.OnStart()
+	if err := tms.BaseService.OnStart(); err != nil {
+		return err
+	}
 
 	tms.mtx.Lock()
 	defer tms.mtx.Unlock()
diff --git a/p2p/types.go b/p2p/types.go
index 1d3770b57..4e0994b71 100644
--- a/p2p/types.go
+++ b/p2p/types.go
@@ -55,12 +55,12 @@ func (info *NodeInfo) CompatibleWith(other *NodeInfo) error {
 }
 
 func (info *NodeInfo) ListenHost() string {
-	host, _, _ := net.SplitHostPort(info.ListenAddr)
+	host, _, _ := net.SplitHostPort(info.ListenAddr) // nolint: errcheck, gas
 	return host
 }
 
 func (info *NodeInfo) ListenPort() int {
-	_, port, _ := net.SplitHostPort(info.ListenAddr)
+	_, port, _ := net.SplitHostPort(info.ListenAddr) // nolint: errcheck, gas
 	port_i, err := strconv.Atoi(port)
 	if err != nil {
 		return -1
diff --git a/p2p/util.go b/p2p/util.go
index 2b85a6cdb..a4c3ad58b 100644
--- a/p2p/util.go
+++ b/p2p/util.go
@@ -7,9 +7,9 @@ import (
 // doubleSha256 calculates sha256(sha256(b)) and returns the resulting bytes.
 func doubleSha256(b []byte) []byte {
 	hasher := sha256.New()
-	hasher.Write(b) // nolint: errcheck
+	hasher.Write(b) // nolint: errcheck, gas
 	sum := hasher.Sum(nil)
 	hasher.Reset()
-	hasher.Write(sum) // nolint: errcheck
+	hasher.Write(sum) // nolint: errcheck, gas
 	return hasher.Sum(nil)
 }
diff --git a/rpc/lib/server/handlers.go b/rpc/lib/server/handlers.go
index 98825be54..2e24195dc 100644
--- a/rpc/lib/server/handlers.go
+++ b/rpc/lib/server/handlers.go
@@ -99,7 +99,11 @@ func funcReturnTypes(f interface{}) []reflect.Type {
 // jsonrpc calls grab the given method's function info and runs reflect.Call
 func makeJSONRPCHandler(funcMap map[string]*RPCFunc, logger log.Logger) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		b, _ := ioutil.ReadAll(r.Body)
+		b, err := ioutil.ReadAll(r.Body)
+		if err != nil {
+			WriteRPCResponseHTTP(w, types.RPCInvalidRequestError("", errors.Wrap(err, "Error reading request body")))
+			return
+		}
 		// if its an empty request (like from a browser),
 		// just display a list of functions
 		if len(b) == 0 {
@@ -108,7 +112,7 @@ func makeJSONRPCHandler(funcMap map[string]*RPCFunc, logger log.Logger) http.Han
 		}
 
 		var request types.RPCRequest
-		err := json.Unmarshal(b, &request)
+		err = json.Unmarshal(b, &request)
 		if err != nil {
 			WriteRPCResponseHTTP(w, types.RPCParseError("", errors.Wrap(err, "Error unmarshalling request")))
 			return
diff --git a/rpc/lib/server/http_server.go b/rpc/lib/server/http_server.go
index 4e0f2bd08..515baf5dd 100644
--- a/rpc/lib/server/http_server.go
+++ b/rpc/lib/server/http_server.go
@@ -56,7 +56,7 @@ func WriteRPCResponseHTTPError(w http.ResponseWriter, httpCode int, res types.RP
 
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(httpCode)
-	w.Write(jsonBytes) // nolint: errcheck
+	w.Write(jsonBytes) // nolint: errcheck, gas
 }
 
 func WriteRPCResponseHTTP(w http.ResponseWriter, res types.RPCResponse) {
@@ -66,7 +66,7 @@ func WriteRPCResponseHTTP(w http.ResponseWriter, res types.RPCResponse) {
 	}
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(200)
-	w.Write(jsonBytes) // nolint: errcheck
+	w.Write(jsonBytes) // nolint: errcheck, gas
 }
 
 //-----------------------------------------------------------------------------
diff --git a/scripts/wal2json/main.go b/scripts/wal2json/main.go
index 2cf40c57d..e44ed4b17 100644
--- a/scripts/wal2json/main.go
+++ b/scripts/wal2json/main.go
@@ -41,10 +41,18 @@ func main() {
 			panic(fmt.Errorf("failed to marshal msg: %v", err))
 		}
 
-		os.Stdout.Write(json)
-		os.Stdout.Write([]byte("\n"))
-		if end, ok := msg.Msg.(cs.EndHeightMessage); ok {
-			os.Stdout.Write([]byte(fmt.Sprintf("ENDHEIGHT %d\n", end.Height)))
+		_, err = os.Stdout.Write(json)
+		if err == nil {
+			_, err = os.Stdout.Write([]byte("\n"))
+		}
+		if err == nil {
+			if end, ok := msg.Msg.(cs.EndHeightMessage); ok {
+				_, err = os.Stdout.Write([]byte(fmt.Sprintf("ENDHEIGHT %d\n", end.Height))) // nolint: errcheck, gas
+			}
+		}
+		if err != nil {
+			fmt.Println("Failed to write message", err)
+			os.Exit(1)
 		}
 	}
 }
diff --git a/types/part_set.go b/types/part_set.go
index d553572f3..e8a0997c0 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -34,7 +34,7 @@ func (part *Part) Hash() []byte {
 		return part.hash
 	} else {
 		hasher := ripemd160.New()
-		hasher.Write(part.Bytes) // nolint: errcheck
+		hasher.Write(part.Bytes) // nolint: errcheck, gas
 		part.hash = hasher.Sum(nil)
 		return part.hash
 	}