Re: [PATCH v12 bpf-next 13/14] selftests/bpf: Add test for d_path helper

From: Jiri Olsa <jolsa@redhat.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Wenbo Zhang <ethercflow@gmail.com>,
	Andrii Nakryiko <andriin@fb.com>,
	Network Development <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>
Subject: Re: [PATCH v12 bpf-next 13/14] selftests/bpf: Add test for d_path helper
Date: Wed, 26 Aug 2020 11:30:30 +0200	[thread overview]
Message-ID: <20200826093030.GB703542@krava> (raw)
In-Reply-To: <CAADnVQ+_X4-eWW_wNDr9G+Ac6LObQeJ5uCxgetGpR2F33BFk5A@mail.gmail.com>

On Tue, Aug 25, 2020 at 04:06:14PM -0700, Alexei Starovoitov wrote:
> On Tue, Aug 25, 2020 at 12:22 PM Jiri Olsa <jolsa@kernel.org> wrote:
> > +
> > +static int trigger_fstat_events(pid_t pid)
> > +{
> > +       int sockfd = -1, procfd = -1, devfd = -1;
> > +       int localfd = -1, indicatorfd = -1;
> > +       int pipefd[2] = { -1, -1 };
> > +       struct stat fileStat;
> > +       int ret = -1;
> > +
> > +       /* unmountable pseudo-filesystems */
> > +       if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
> > +               return ret;
> > +       /* unmountable pseudo-filesystems */
> > +       sockfd = socket(AF_INET, SOCK_STREAM, 0);
> > +       if (CHECK(sockfd < 0, "trigger", "scoket failed\n"))
> > +               goto out_close;
> > +       /* mountable pseudo-filesystems */
> > +       procfd = open("/proc/self/comm", O_RDONLY);
> > +       if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
> > +               goto out_close;
> > +       devfd = open("/dev/urandom", O_RDONLY);
> > +       if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
> > +               goto out_close;
> > +       localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY);
> 
> The work-in-progress CI caught a problem here:
> 
> In file included from /usr/include/fcntl.h:290:0,
> 4814                 from ./test_progs.h:29,
> 4815                 from
> /home/travis/build/tsipa/bpf-next/tools/testing/selftests/bpf/prog_tests/d_path.c:3:
> 4816In function ‘open’,
> 4817    inlined from ‘trigger_fstat_events’ at
> /home/travis/build/tsipa/bpf-next/tools/testing/selftests/bpf/prog_tests/d_path.c:50:10,
> 4818    inlined from ‘test_d_path’ at
> /home/travis/build/tsipa/bpf-next/tools/testing/selftests/bpf/prog_tests/d_path.c:119:6:
> 4819/usr/include/x86_64-linux-gnu/bits/fcntl2.h:50:4: error: call to
> ‘__open_missing_mode’ declared with attribute error: open with O_CREAT
> or O_TMPFILE in second argument needs 3 arguments
> 4820    __open_missing_mode ();
> 4821    ^~~~~~~~~~~~~~~~~~~~~~

ok, looks like it's missing the permission bits

> 
> I don't see this bug in my setup, since I'm using an older glibc that
> doesn't have this check,
> so I've pushed it anyway since it was taking a bit long to land and folks were
> eagerly waiting for the allowlist and d_path features.
> But some other folks may complain about build breakage really soon.
> So please follow up asap.

time to upadte my systems, I'm missing new warnings ;-)

I'll send the fix

thanks,
jirka