[LTP] [REGRESSION] Broken tests using tst_net.sh by 893ca0abe7 (was: [PATCH 1/2] lib: multiply the timeout if detect slow kconfigs)

[Li Wang]

On Thu, Jan 16, 2025 at 6:42 AM Petr Vorel <pvorel@suse.cz> wrote:

> Hi Li, Cyril, all,
>
> ...
> > +++ b/lib/tst_test.c
> > @@ -555,9 +555,6 @@ static int multiply_runtime(int max_runtime)
>
> >       parse_mul(&runtime_mul, "LTP_RUNTIME_MUL", 0.0099, 100);
>
> > -     if (tst_has_slow_kconfig())
> > -             max_runtime *= 4;
> > -
> >       return max_runtime * runtime_mul;
> >  }
>
> > @@ -1706,6 +1703,9 @@ unsigned int tst_multiply_timeout(unsigned int
> timeout)
> >       if (timeout < 1)
> >               tst_brk(TBROK, "timeout must to be >= 1! (%d)", timeout);
>
> > +     if (tst_has_slow_kconfig())
> > +             timeout *= 4;
>
> FYI this change, merged as 893ca0abe7 ("lib: multiply the timeout if
> detect slow
> kconfigs") caused a regression on *all* tests which use tst_net.sh.
>
> First, it detects slow config on everything which uses struct tst_test,
> which are unfortunately some tools at testcases/lib/:
>
> $ git grep -l "struct tst_test" testcases/lib/*.c
> testcases/lib/tst_device.c // not obvious reason, might be removed
> testcases/lib/tst_get_free_pids.c // force messages to be printed from new
> library
> testcases/lib/tst_ns_create.c // .forks_child = 1, Needed by SAFE_CLONE
> testcases/lib/tst_ns_exec.c  // .forks_child = 1, Needed by SAFE_CLONE
> testcases/lib/tst_run_shell.c // not obvious reason, might be removed
>
> Besides unimportant fact that slow config detection is an unnecessary
> slowdown
> on these tools, the problem is that it prints messages to stderr, which
> causes
> breakage.
>
> Previously tst_ns_exec.c run just command passed by -c parameter:
>
> $ ./tst_ns_exec 14536 net,mnt sh -c " cat
> /proc/sys/net/ipv6/conf/ltp_ns_veth1/disable_ipv6"
> 0
>
> Now it prints TINFO:
> $ ./tst_ns_exec 14536 net,mnt sh -c " cat
> /proc/sys/net/ipv6/conf/ltp_ns_veth1/disable_ipv6"
> tst_kconfig.c:88: TINFO: Parsing kernel config '/proc/config.gz'
> tst_kconfig.c:667: TINFO: CONFIG_LATENCYTOP kernel option detected which
> might slow the execution
> 0
>
> tst_rhost_run() in tst_net.sh runs binary on remote host:
>
>         output=$($rcmd "$sh_cmd" $out 2>&1 || echo 'RTERR')
>
> Redirect stderr to stdout (2>&1) is likely needed for some tests. But
> tst_rhost_run() output is often parsed including therefore certain tools in
> testcases/lib/ have to print only expected output:
>
> init_ltp_netspace()
> {
>         ...
>                 pid="$(ROD tst_ns_create net,mnt)"
>         ...
>         export LTP_NETNS="${LTP_NETNS:-tst_ns_exec $pid net,mnt}"
>
> I will probably solve it by adding yet another parameter to
> tst_rhost_run(),
> which ignores stderr and use it for tst_ns_{create,exec}. But maybe there
> is
> another solution (or another problem).
>

Or, another way is just to set 'tst_test->timeout == TST_UNLIMITED_TIMEOUT'
in those testcase/lib tools.


-- 
Regards,
Li Wang