[LTP] [PATCH] syscalls/keyctl02: wait for last key to be garbage collected

[Jan Stancek]

----- Original Message -----
> Hi!
> > +	/*
> > +	 * Kernel should start garbage collect when last reference to key
> > +	 * is removed (see key_put()). Since we are adding keys with identical
> > +	 * description and type, each replacement should schedule a gc run,
> > +	 * see comment at __key_link().
> > +	 *
> > +	 * We create extra key here, to remove reference to last revoked key.
> > +	 */
> > +	key_inv = add_key("user", "ltptestkey", "foo", 3,
> > +		KEY_SPEC_PROCESS_KEYRING);
> > +	if (key_inv == -1)
> > +		tst_brk(TBROK | TERRNO, "Failed to add key");
> > +#ifdef KEYCTL_INVALIDATE
> > +	/*
> > +	 * If we have invalidate, we can drop extra key immediately as well,
> > +	 * which also schedules gc.
> > +	 */
> > +	if (keyctl(KEYCTL_INVALIDATE, key_inv))
> > +		tst_brk(TBROK | TERRNO, "Failed to invalidate key");
> 
> We should probably handle the situation where someone compiles this code
> on newer userspace and runs it on older kernel than 3.5, I suppose that
> we will get -1 with EINVAL or EOPNOTSUPP here.
> 
> And if that is handled we can also drop the ifdef in favor of fallback
> definition.

Agreed, I'll test on some ancient kernel and send v2.

Regards,
Jan

> 
> 
> Otherwise this looks good.
> 
> --
> Cyril Hrubis
> chrubis@suse.cz
>