[client] Fix statemanager possible deadlock

1. Stop() takes m.mu.Lock() and defers m.mu.Unlock()
2. <-m.done under lock
3. periodicStateSave defers close(m.done)
4. periodicStateSave calls PersistState() (line 256) which does m.mu.Lock()

Double Stop() remains idempotent: second cancel() on dead ctx
 (no-op) and reads done already closed (immediate return).

client/internal/statemanager/manager.go

@@ -96,17 +96,19 @@ func (m *Manager) Stop(ctx context.Context) error {
 	}
 
 	m.mu.Lock()
-	defer m.mu.Unlock()
+	cancel := m.cancel
+	done := m.done
+	m.mu.Unlock()
 
-	if m.cancel == nil {
+	if cancel == nil {
 		return nil
 	}
-	m.cancel()
+	cancel()
 
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
-	case <-m.done:
+	case <-done:
 	}
 
 	return nil

client/system/info_linux.go

@@ -3,14 +3,15 @@
 package system
 
 import (
+	"bytes"
 	"context"
 	"os"
+	"os/exec"
 	"regexp"
 	"runtime"
+	"strings"
 	"time"
 
-	"golang.org/x/sys/unix"
-
 	log "github.com/sirupsen/logrus"
 	"github.com/zcalusic/sysinfo"
 
@@ -28,14 +29,19 @@ func UpdateStaticInfoAsync() {
 
 // GetInfo retrieves and parses the system information
 func GetInfo(ctx context.Context) *Info {
-	var uts unix.Utsname
-	if err := unix.Uname(&uts); err != nil {
-		return nil
+	info := _getInfo()
+	for strings.Contains(info, "broken pipe") {
+		info = _getInfo()
+		time.Sleep(500 * time.Millisecond)
 	}
 
+	osStr := strings.ReplaceAll(info, "\n", "")
+	osStr = strings.ReplaceAll(osStr, "\r\n", "")
+	osInfo := strings.Split(osStr, " ")
+
 	osName, osVersion := readOsReleaseFile()
 	if osName == "" {
-		osName = unix.ByteSliceToString(uts.Sysname[:])
+		osName = osInfo[3]
 	}
 
 	systemHostname, _ := os.Hostname()
@@ -52,8 +58,8 @@ func GetInfo(ctx context.Context) *Info {
 	}
 
 	gio := &Info{
-		Kernel:             unix.ByteSliceToString(uts.Sysname[:]),
-		Platform:           unix.ByteSliceToString(uts.Machine[:]),
+		Kernel:             osInfo[0],
+		Platform:           osInfo[2],
 		OS:                 osName,
 		OSVersion:          osVersion,
 		Hostname:           extractDeviceName(ctx, systemHostname),
@@ -61,7 +67,7 @@ func GetInfo(ctx context.Context) *Info {
 		CPUs:               runtime.NumCPU(),
 		NetbirdVersion:     version.NetbirdVersion(),
 		UIVersion:          extractUserAgent(ctx),
-		KernelVersion:      unix.ByteSliceToString(uts.Release[:]),
+		KernelVersion:      osInfo[1],
 		NetworkAddresses:   addrs,
 		SystemSerialNumber: si.SystemSerialNumber,
 		SystemProductName:  si.SystemProductName,
@@ -72,6 +78,20 @@ func GetInfo(ctx context.Context) *Info {
 	return gio
 }
 
+func _getInfo() string {
+	cmd := exec.Command("uname", "-srio")
+	cmd.Stdin = strings.NewReader("some")
+	var out bytes.Buffer
+	var stderr bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &stderr
+	err := cmd.Run()
+	if err != nil {
+		log.Warnf("getInfo: %s", err)
+	}
+	return out.String()
+}
+
 func sysInfo() (string, string, string) {
 	isascii := regexp.MustCompile("^[[:ascii:]]+$")
 	si := getSystemInfo()