Date:   Mon, 23 Jan 2023 11:25:40 -0800
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Willy Tarreau <w@1wt.eu>
Cc:     Ammar Faizi <ammarfaizi2@gnuweeb.org>,
        linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
        linux-kselftest@vger.kernel.org
Subject: Re: [PATCH 0/2] selftests/nolibc: small simplification of test
 development phase
Message-ID: <20230123192540.GZ2948950@paulmck-ThinkPad-P17-Gen-1>
Reply-To: paulmck@kernel.org
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On Mon, Jan 23, 2023 at 08:12:50PM +0100, Willy Tarreau wrote:
> On Mon, Jan 23, 2023 at 09:40:03AM -0800, Paul E. McKenney wrote:
> > Except that when I install Ubuntu 20.04's version, I get this:
> > 
> > ------------------------------------------------------------------------
> > 
> > $ sudo make run-user
> >   MKDIR   sysroot/x86/include
> > make[1]: Entering directory '/home/git/linux-rcu/tools/include/nolibc'
> > make[2]: Entering directory '/home/git/linux-rcu'
> > make[2]: Leaving directory '/home/git/linux-rcu'
> > make[2]: Entering directory '/home/git/linux-rcu'
> >   INSTALL /home/git/linux-rcu/tools/testing/selftests/nolibc/sysroot/sysroot/include
> > make[2]: Leaving directory '/home/git/linux-rcu'
> > make[1]: Leaving directory '/home/git/linux-rcu/tools/include/nolibc'
> >   CC      nolibc-test
> > 32 gettimeofday_null = -1 EFAULT        [FAIL]
> > See all results in /home/git/linux-rcu/tools/testing/selftests/nolibc/run.out
> > 
> > ------------------------------------------------------------------------
> > 
> > I have attached run.out.
> > 
> > In contrast, with my hand-built qemu-x86_64, all tests passed.
> > 
> > This might be just a version-related bug, but figured I should let you
> > guys know.
> 
> Interesting. Maybe something differs in the way it passes expectedly
> invalid pointers to some syscalls. Keep in mind that it's using your
> local kernel also, that could make a difference. I'm not that much keen
> on trying to investigate that one to be honest, given that this user
> mode is really meant to ease the life of test developers like Ammar
> and myself who just want to focus on the correctness of the test they're
> adding and not that much on the validity of the test itself in this
> context. I suggest we keep this one in mind without putting too much
> effort on it for now.

Indeed, it is easy for me to remove qemu-user and re-install my
hand-built version.  In fact, I just now did this and verified that
everything now passes.  ;-)

							Thanx, Paul