Re: [PATCH] tty: fix tty->ldisc leak on ENODEV from driver install

[Julian Anastasov]

	Hello,

On Wed, 23 Mar 2011, Jiri Slaby wrote:

> > --- linux-2.6.38/drivers/tty/tty_io.c
> > +++ linux-2.6.38/drivers/tty/tty_io.c
> > @@ -188,6 +188,7 @@ void free_tty_struct(struct tty_struct *
> >  		put_device(tty->dev);
> >  	kfree(tty->write_buf);
> >  	tty_buffer_free_all(tty);
> > +	kfree(tty->ldisc);
>
> We should not mess up with ldisc here. We should call something like
> tty_ldisc_deinit from tty_init_dev on fail path. The deinit should drop
> the reference (call put_ldisc). Or maybe even deinitialize_tty_struct ->
> tty_ldisc_deinit -> put_ldisc).
>
> Note that your way you do not drop the module refcount of ld ops.

	Right, that is what I found before going to sleep.
> From the visible functions I see that currently only
tty_ldisc_deref does exactly what we need. But I suspect
it should be used for other purposes. I assume the authors
have a better idea what to do here. Let me know if I need
to test a better patch.

> >  	kfree(tty);
> >  }
>
> regards,
> --
> js
> suse labs

Regards

--
Julian Anastasov <ja@xxxxxx>
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