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From:   Sven Schnelle <svens@linux.ibm.com>
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     Willy Tarreau <w@1wt.eu>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] nolibc: add support for the s390 platform
References: <20230109080910.26594-1-w@1wt.eu>
        <20230109191534.GU4028633@paulmck-ThinkPad-P17-Gen-1>
        <20230110073242.GB3229@1wt.eu> <20230110092517.GA4626@1wt.eu>
        <20230110145334.GL4028633@paulmck-ThinkPad-P17-Gen-1>
        <20230110161249.GB4649@1wt.eu>
        <20230110163210.GP4028633@paulmck-ThinkPad-P17-Gen-1>
Date:   Wed, 11 Jan 2023 07:45:05 +0100
In-Reply-To: <20230110163210.GP4028633@paulmck-ThinkPad-P17-Gen-1> (Paul
        E. McKenney's message of "Tue, 10 Jan 2023 08:32:10 -0800")
Message-ID: <yt9dh6wxa7ta.fsf@linux.ibm.com>
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"Paul E. McKenney" <paulmck@kernel.org> writes:

> On Tue, Jan 10, 2023 at 05:12:49PM +0100, Willy Tarreau wrote:
>> On Tue, Jan 10, 2023 at 06:53:34AM -0800, Paul E. McKenney wrote:
>> > Here is one of them, based on both the fixes and Sven's s390 support.
>> > Please let me know if you need any other combination.
>> 
>> Thanks, here's the problem:
>> 
>> > 0 getpid = 1                             [OK]
>> > 1 getppid = 0                            [OK]
>> > 3 gettid = 1                             [OK]
>> > 5 getpgid_self = 0                       [OK]
>> > 6 getpgid_bad = -1 ESRCH                 [OK]
>> > 7 kill_0[    1.940442] tsc: Refined TSC clocksource calibration: 2399.981 MHz
>> > [    1.942334] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x229825a5278, max_idle_ns: 440795306804 ns
>> >  = 0                             [OK]
>> > 8 kill_CONT = 0           [    1.944987] clocksource: Switched to clocksource tsc
>> >                [OK]
>> > 9 kill_BADPID = -1 ESRCH                 [OK]
>> (...)
>> 
>> It's clear that "grep -c ^[0-9].*OK" will not count all of them (2 are
>> indeed missing).
>> 
>> We could probably start with "quiet" but that would be against the
>> principle of using this to troubleshoot issues. I think we just stick
>> to the current search of "FAIL" and that as long as a success is
>> reported and the number of successes is within the expected range
>> that could be OK. At least I guess :-/
>
> Huh.  Would it make sense to delay the start of the nolibc testing by a
> few seconds in order to avoid this sort of thing?  Or would that cause
> other problems?

Or define a second serial port (or something similar) in qemu and run the
kernel console on ttyS0, and the init process writes to /dev/ttyS1? So the
output of the test program could be redirected to a file on the host?