[LTP] [PATCH v2 3/3] syscalls/clock_adjtime: create clock_adjtime syscall tests

[Cyril Hrubis]

Hi!
> > +	/*
> > +	 * special case: EFAULT for NULL pointers
> > +	 * txcptr = tst_get_bad_addr() -> SIGSEGV is thrown (and not EFAULT)
> > +	 */
> > +
> > +	if (tc[i].exp_err == EFAULT)
> > +		txcptr = NULL;
> 
> Cyril,
> 
> clock_adjtime() returns an EFAULT in case copy_from_user() returns
> errors.
> 
> Thing is that, using tst_get_bad_addr(), and having a page with no
> permissions, before getting an error from copy_from_user() and returning
> - thus getting EFAULT back - we get a SIGSEGV from _copy_from_user()
> itself, because it tries to sanitize given address, with memset(0),
> before returning to userland (to avoid leaks of some sort ?).
> 
> With this, the EFAULT is only got when using NULL pointers, and not a
> *bad* pointer??? So, right now, I can???tuse tst_get_bad_addr() like you
> suggested. Should I remove this test and send a v3 ?

Hmm that's strange, memseting the structure does not make much sense.

-- 
Cyril Hrubis
chrubis@suse.cz