[LTP] [PATCH v2 8/8] Rewrite userns08.c using new LTP API

[Cyril Hrubis]

Hi!
> ./userns08 -i50
> tst_kconfig.c:82: TINFO: Parsing kernel config '/proc/config.gz'
> tst_test.c:1456: TINFO: Timeout per run is 0h 05m 00s
> 
> userns08.c:65: TPASS: Denied write access to ./restricted : EACCES (13)
> userns08.c:65: TPASS: Denied write access to ./restricted : EACCES (13)
> userns08.c:65: TPASS: Denied write access to ./restricted : EACCES (13)
> userns08.c:65: TPASS: Denied write access to ./restricted : EACCES (13)
> userns08.c:65: TPASS: Denied write access to ./restricted : EACCES (13)
> userns08.c:36: TBROK: clone3 failed: ENOSPC (28)
> 
> Something needs to be closed after each run.

ENOSPC means that we created too many user namespaces. The problem is
likely that we are creating the namespaces faster than they are being
asynchronously cleaned up in the kernel. Adding sleep(1) to the
clone_newuser() function gives kernel enough time to clean the
namespaces and the test works with any -i. Also note that we get the
exact same failure if we execute the test a few times in a row, i.e.

for i in `seq 10`; do
	./userns08
done

The original test fails in the same way, so while it should be fixed,
it's not really reason to block this patchset.

And the only correct fix would be retrying the clone() on ENOSPC in the
SAFE_CLONE().

-- 
Cyril Hrubis
chrubis@suse.cz