Re: [PATCH mptcp-net] selftests: mptcp: don't exit when a symbol not found

[Geliang Tang <geliang@kernel.org>]

On Thu, Feb 22, 2024 at 09:58:39AM +0100, Matthieu Baerts wrote:
> Hi Geliang,
> 
> On 22/02/2024 8:56 am, Geliang Tang wrote:
> > From: Geliang Tang <tanggeliang@kylinos.cn>
> > 
> > mptcp_lib_kallsyms_has() will always exit when a symbol has not found, it
> > breaks the test itself. Unexpected errors occur:
> > 
> >  007 userspace pm add & remove address
> >        syn                                 [ OK ]
> >        synack                              [ OK ]
> >        ack                                 [ OK ]
> >        add                                 [ OK ]
> >        echo                                [ OK ]
> >        mptcp_info subflows=2:2             [ OK ]
> >        mptcp_info subflows_total=3:3       [ OK ]
> >        mptcp_info add_addr_signal=2:2      [ OK ]
> >        mptcp_info last_data_sent=191:18    [ OK ]
> >        mptcp_info last_data_recv=40:68     [ OK ]
> >        mptcp_info last_ack_recv=93:74      [ OK ]
> >        dump addrs signal                   ERROR: missing feature: \
> > 			mptcp_userspace_pm_dump_addr$ symbol not found
> >  Cannot open network namespace "ns1-65d6fb5a-5FviVK": \
> > 			No such file or directory
> >  Cannot open network namespace "ns2-65d6fb5a-5FviVK": \
> > 			No such file or directory
> >  cmp: /tmp/tmp.a7osJs7Nj0: No such file or directory
> >  cmp: /tmp/tmp.f02z6brCQu: No such file or directory
> >  cat: /tmp/tmp.27TzxD2efV: No such file or directory
> > not ok 1 test: selftest_mptcp_join # FAIL
> > 
> > To fix this, this patch adds a new argument 'continue' for the helper
> > mptcp_lib_fail_if_expected_feature() to control whether exit or not.
> > 
> > Always set this argument to 1 in mptcp_lib_kallsyms_has().
> > 
> > Fixes: 83013bdf90a ("selftests: mptcp: connect: skip if MPTCP is not supported")
> 
> I'm not sure to understand why you sent this :)

Say in the test "signal addresses race test":

                if ! mptcp_lib_kallsyms_has "mptcp_pm_subflow_check_next$"; then
                        chk_join_nr 3 3 2
                        chk_add_nr 4 4
                else
                        chk_join_nr 3 3 3
                        # the server will not signal the address terminating
                        # the MPC subflow
                        chk_add_nr 3 3
                fi

This code will never run to this block:

                        chk_join_nr 3 3 2
                        chk_add_nr 4 4

Since if no symbal of mptcp_pm_subflow_check_next, mptcp_lib_kallsyms_has exit.

You can trigger this by renaming "mptcp_pm_subflow_check_next$" to
"no_mptcp_pm_subflow_check_next$", an non-exist function name, for test.

Thanks,
-Geliang

> 
> The fixes commit ('d' is missing at the beginning) here mentions:
> 
> > Note that this check can also
> > mark the test as failed if 'SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES' env
> > var is set to 1: by doing that, we can make sure a test is not being
> > skipped by mistake.
> 
> So the goal is to fail when the env var is set. Otherwise, we would miss
> tests that are skipped by accident.
> 
> If you use 'mptcp-upstream-virtme-docker' and you want to run recent
> selftests on an older kernel, you can add this to the docker command not
> to exit if a feature is missing:
> 
>   -e INPUT_SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES=0
> 
> But clearly here, we don't want to continue if we expect all features to
> work!
> 
> Cheers,
> Matt
> -- 
> Sponsored by the NGI0 Core fund.