更新文件中的错误 - 当没有会话时，尝试获取非对象的属性

I have a form for the user edit his profile account. So it appears for each field the value if there is a value for each field with: "value="{{$user->name}}". But sometimes is appearing this error:

Trying to get property of non-object

Do you know how to correct the issue?

<form method="post" action="{{route('user.update')}}">
    {{csrf_field()}}
    <div>
        <label for="name">Name</label>
        <input type="text" value="{{$user->name}}" name="name" class="form-control" id="name">
    </div>
    <div>
        <label for="surname">Surname</label>
        <input type="text" value="{{$user->surname}}" name="surname" class="form-control" id="surname">
    </div>
    <!-- other fields -->
    <input type="submit" value="Update"/>
</form>

The update method:

 public function updateGeneralInfo(Request $request){

        $this->validate($request, [
            'name' => 'required',
        ]);

        $user = Auth::user();
        $user->name = $request->name;
        ...
        $user->save();

        return redirect()->back();
    }

In your controller you can do a check before you return the view:

if(Auth::check()){
    //return view and other stuff
}
else {
    //redirect to login
}

In your blade:

<form method="post" action="{{route('user.update')}}">
    {{csrf_field()}}
    <div>
        <label for="name">Name</label>
        <input type="text" value="{{auth()->user()->name}}" name="name" class="form-control" id="name">
    </div>
    <div>
        <label for="surname">Surname</label>
        <input type="text" value="{{auth()->user()->surname}}" name="surname" class="form-control" id="surname">
    </div>
    <!-- other fields -->
    <input type="submit" value="Update"/>
</form>