[LTP] [PATCH 2/2] mq_timedreceive01: Workaround segfault on libc variant on 32 bit

[Petr Vorel]

Hi all,

> On Tue, Nov 12, 2024 at 06:18:31PM +0100, Petr Vorel wrote:
> > EFAULT test segfaults on newer kernels (e.g. 6.4) on libc variant on
> > 32bit.  Similarly to 1d4d5a0750 use typical LTP workaround to test by
> > forked child + checking the terminating signal.

...
> > +	unsigned int j;
> > +	unsigned int prio;

> >  	if (tc->invalid_msg)
> >  		len -= 1;
> > @@ -208,6 +192,60 @@ static void do_test(unsigned int i)
> >  			TST_RET, prio, len);
> >  }

> > +static void test_bad_addr(unsigned int i)
> > +{
> > +	struct time64_variants *tv = &variants[tst_variant];
> > +	pid_t pid;
> > +	int status;
> > +
> > +	pid = SAFE_FORK();
> > +	if (!pid) {
> > +		verify_mqt_receive(i, pid);
> > +		_exit(0);
> nit:
> If this is a normal exit, i suggest use s/_exit(0)/exit(0) ?

I copy pasted this from similar tests. IMHO both should work. According to man
exit() calls functions registered with atexit() and _exit(), _exit() just
immediately terminates the process. Any open file descriptors belonging to the process are closed.

@Jan, @Cyril Please correct me if I'm wrong.

Kind regards,
Petr

> > +	}
> > +
> > +	SAFE_WAITPID(pid, &status, 0);
> > +
> > +	if (WIFEXITED(status) && !WEXITSTATUS(status))
> > +		return;
> > +
> > +	if (tv->ts_type == TST_LIBC_TIMESPEC &&
> > +		WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV) {
> > +		tst_res(TPASS, "Child killed by expected signal");
> > +		return;
> > +	}
> > +
> > +	tst_res(TFAIL, "Child %s", tst_strstatus(status));
> > +}
...