fix: Avoid locking on app lifecycle change

Author: alexjba

pkg/backend/geth_backend.go

@@ -79,7 +79,8 @@ type LoginParams struct {
 
 // StatusBackend implements the Status.im service over go-ethereum
 type StatusBackend struct {
-	mu sync.Mutex
+	mu          sync.Mutex
+	lifecycleMu sync.Mutex
 	// rootDataDir is the same for all networks.
 	rootDataDir string
 	appDB       *sql.DB
@@ -2048,19 +2049,27 @@ func (b *StatusBackend) getVerifiedWalletAccount(address, password string) (*gen
 // AppStateChange handles app state changes (background/foreground).
 // state values: see https://facebook.github.io/react-native/docs/appstate.html
 func (b *StatusBackend) AppStateChange(state AppState) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
 	if !state.IsValid() {
 		b.logger.Warn("invalid app state, not reporting app state change", zap.Any("state", state))
 		return
 	}
 
+	b.mu.Lock()
 	b.appState = state
-
 	if b.statusNode == nil {
 		b.logger.Warn("statusNode nil, applying app state change without running node")
 	}
+	b.mu.Unlock()
+
+	b.lifecycleMu.Lock()
+	defer b.lifecycleMu.Unlock()
+
+	if state == AppStateForeground && b.lifecycleState == AppLifecycleRunning {
+		return
+	}
+	if state != AppStateForeground && b.lifecycleState == AppLifecyclePausedBackground {
+		return
+	}
 
 	if state == AppStateForeground {
 		if err := b.resumeLocked(); err != nil {
@@ -2092,6 +2101,10 @@ func (b *StatusBackend) StartLocalNotifications() error {
 func (b *StatusBackend) Logout() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
+	// Drain any in-progress AppStateChange transition before stopping the node.
+	// Lock order is always b.mu → lifecycleMu to prevent deadlock.
+	b.lifecycleMu.Lock()
+	defer b.lifecycleMu.Unlock()
 
 	b.logger.Debug("logging out")
 

pkg/backend/pause_play.go

@@ -3,6 +3,7 @@ package backend
 import (
 	"fmt"
 
+	"github.com/status-im/status-go/pkg/backend/node"
 	"github.com/status-im/status-go/protocol"
 )
 
@@ -18,9 +19,11 @@ const (
 
 func (s AppLifecycleState) String() string { return string(s) }
 
+// LifecycleState returns the current backend lifecycle state.
+// Requires lifecycleMu since lifecycleState is written by pause/resumeLocked.
 func (b *StatusBackend) LifecycleState() AppLifecycleState {
-	b.mu.Lock()
-	defer b.mu.Unlock()
+	b.lifecycleMu.Lock()
+	defer b.lifecycleMu.Unlock()
 	return b.lifecycleState
 }
 
@@ -31,14 +34,19 @@ func (b *StatusBackend) pauseLocked() error {
 	if b.lifecycleState == AppLifecyclePausedBackground {
 		return nil
 	}
-	if b.statusNode == nil || !b.statusNode.IsRunning() {
+	// Snapshot statusNode pointer under b.mu to avoid data race with Logout.
+	b.mu.Lock()
+	sn := b.statusNode
+	b.mu.Unlock()
+
+	if sn == nil || !sn.IsRunning() {
 		b.lifecycleState = AppLifecycleStopped
 		return nil
 	}
-	if messenger := b.currentMessengerLocked(); messenger != nil {
+	if messenger := b.currentMessenger(sn); messenger != nil {
 		messenger.ToBackground()
 	}
-	if err := b.statusNode.PauseBackground(); err != nil {
+	if err := sn.PauseBackground(); err != nil {
 		return fmt.Errorf("pause background: %w", err)
 	}
 	b.lifecycleState = AppLifecyclePausedBackground
@@ -52,25 +60,30 @@ func (b *StatusBackend) resumeLocked() error {
 	if b.lifecycleState == AppLifecycleRunning {
 		return nil
 	}
-	if b.statusNode == nil || !b.statusNode.IsRunning() {
+	// Snapshot statusNode pointer under b.mu to avoid data race with Logout.
+	b.mu.Lock()
+	sn := b.statusNode
+	b.mu.Unlock()
+
+	if sn == nil || !sn.IsRunning() {
 		b.lifecycleState = AppLifecycleStopped
 		return nil
 	}
-	if messenger := b.currentMessengerLocked(); messenger != nil {
+	if messenger := b.currentMessenger(sn); messenger != nil {
 		messenger.ToForeground()
 	}
 
 	b.lifecycleState = AppLifecycleResumingForeground
-	if err := b.statusNode.ResumeForeground(); err != nil {
+	if err := sn.ResumeForeground(); err != nil {
 		return fmt.Errorf("resume foreground: %w", err)
 	}
 	b.lifecycleState = AppLifecycleRunning
 	return nil
 }
 
-func (b *StatusBackend) currentMessengerLocked() *protocol.Messenger {
-	if b.statusNode == nil || b.statusNode.WakuV2ExtService() == nil {
+func (b *StatusBackend) currentMessenger(sn *node.StatusNode) *protocol.Messenger {
+	if sn == nil || sn.WakuV2ExtService() == nil {
 		return nil
 	}
-	return b.statusNode.WakuV2ExtService().Messenger()
+	return sn.WakuV2ExtService().Messenger()
 }