[PATCH v2 1/3] fs: Introduce task path helpers

[Chen Linxuan]

On Tue, Sep 22, 2026 at 3:21 AM Jann Horn <jannh at google.com> wrote:
>
> On Mon, Aug 31, 2026 at 4:59 AM Chen Linxuan via B4 Relay
> <devnull+me.black-desk.cn at kernel.org> wrote:
> > Introduce helpers that acquire a referenced struct path for a task's
> > executable, root, and working directory. Reuse them for procfs task
> > links and AppArmor executable-path handling instead of duplicating file
> > and path reference handling at each call site.
> [...]
> > +/**
> > + * get_task_exe_path - acquire a reference to the task's executable path
> > + * @task: The task.
> > + * @exe_path: The task's executable path.
> > + *
> > + * Returns 0 if the task has an executable path, or -ENOENT if it does not.
> > + * The caller must release the path through path_put() on success.
> > + */
> > +int get_task_exe_path(struct task_struct *task, struct path *exe_path)
> > +{
> > +       struct file *exe_file = get_task_exe_file(task);
> > +
> > +       if (!exe_file)
> > +               return -ENOENT;
> > +
> > +       *exe_path = exe_file->f_path;
> > +       path_get(exe_path);
> > +       fput(exe_file);
> > +       return 0;
> > +}
> [...]
> >  static const char *get_current_exe_path(char *buffer, int buffer_size)
> >  {
> > -       struct file *exe_file;
> > -       struct path p;
> > +       struct path p __free(path_put) = {};
> >         const char *path_str;
> >
> > -       exe_file = get_task_exe_file(current);
> > -       if (!exe_file)
> > +       if (get_task_exe_path(current, &p))
> >                 return ERR_PTR(-ENOENT);
>
> This assumes that when get_task_exe_path() fails, it doesn't set
> members of the path argument to non-NULL values. That should be noted
> in a comment above get_task_exe_path().

Will be updated in V3.

>