Re: [PATCH 2/2] Add test for target_set tapset.

[Josh Stone <jistone at redhat dot com>]

On 06/18/2009 03:33 PM, Przemyslaw Pawelczyk wrote:
> +proc abort {} {
> +	global test
> +	fail $test
> +	exit
> +}

exit should not be used, because that will stop the entire testing
session.  We don't want failure here to prevent other tests from running.

> +	set pid_it $stp_pid
> +	while {[info exists pid_array($pid_it)]} {
> +		if {[exec pgrep -P $pid_it] != $pid_array($pid_it)} {
> +			abort
> +		}
> +		set pid_it $pid_array($pid_it)
> +	}

There's a race here that the sleep process might finish before pgrep
sees it.  Most of the time, one second will probably be plenty of time,
but on a slow and/or loaded system we could have false failures.

What if you just used an absurdly long timeout for sleep, and then "kill
-INT" it after you've verified the chain?

> +probe nd_syscall.nanosleep
> +{
> +	if (target_set_pid(pid()) && @cast(req_uaddr, "timespec", "<linux/time.h>")->tv_sec == $1)
> +		target_set_report()
> +}

Some systems have a 32-bit userspace with a 64-bit kernel, and in that
case you would need to catch nd_syscall.compat_nanosleep as well.


I feel like you're going through somewhat heroic efforts to validate
this in tcl, and you're not able to use any of the common infrastructure
we have for other tests.  Maybe it would easier to check results within
the script?  We couldn't check the report() that way, but
target_set_pid() is what we really care about anyway, right?

I'm imagining that in the nanosleep probe, you could recursively walk up
task_parent() until you hit stp_pid() or 1 (init).  Then as the
recursion unwinds, make sure that target_set_pid() matches.  You can use
system() to also launch a sleep that's outside of the target_set.  Does
that make sense?


Josh