Re: [PATCH] proc: s_fs_info may be NULL when proc_kill_sb is called

[Al Viro]

On Wed, Jun 10, 2020 at 12:12:54PM -0500, Eric W. Biederman wrote:

> >  {
> >     struct proc_fs_info *fs_info = proc_sb_info(sb);
> >  
> > -   if (fs_info->proc_self)
> > -           dput(fs_info->proc_self);
> > +   if (fs_info) {
> > +           if (fs_info->proc_self)
> > +                   dput(fs_info->proc_self);
> >  
> > -   if (fs_info->proc_thread_self)
> > -           dput(fs_info->proc_thread_self);
> > +           if (fs_info->proc_thread_self)
> > +                   dput(fs_info->proc_thread_self);
> > +
> > +           put_pid_ns(fs_info->pid_ns);
> > +           kfree(fs_info);

While we are at it, dput(NULL) is an explicit no-op.