Re: [PATCH 7/8] cachefiles: Fix NULL pointer dereference in object->file

[Zizhi Wo <wozizhi@xxxxxxxxxx>]

在 2024/10/10 19:26, David Howells 写道:
> Zizhi Wo <wozizhi@xxxxxxxxxx> wrote:
>
> > +	spin_lock(&object->lock);
> >   	if (object->file) {
> >   		fput(object->file);
> >   		object->file = NULL;
> >   	}
> > +	spin_unlock(&object->lock);
>
> I would suggest stashing the file pointer in a local var and then doing the
> fput() outside of the locks.
>
> David

If fput() is executed outside the lock, I am currently unsure how to
guarantee that file in __cachefiles_write() does not trigger null
pointer dereference...

Thanks,
Zizhi Wo