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From: Joe Stringer <joe@wand.net.nz>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Joe Stringer <joe@wand.net.nz>, bpf <bpf@vger.kernel.org>,
	Lorenz Bauer <lmb@cloudflare.com>,
	Networking <netdev@vger.kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>, Martin Lau <kafai@fb.com>
Subject: Re: [PATCHv2 bpf-next 5/5] selftests: bpf: add test for sk_assign
Date: Thu, 26 Mar 2020 14:38:41 -0700	[thread overview]
Message-ID: <CAOftzPjcvZ8Xyy3seLfXCEiasjAE-Sy8cwuOSou35X9fVr9jXg@mail.gmail.com> (raw)
In-Reply-To: <CAEf4Bza=fiCdXacf3pmdXGiiLx0U1qBKHbbjN-=AEvTZ+S8q0A@mail.gmail.com>

On Thu, Mar 26, 2020 at 12:37 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Mar 25, 2020 at 10:28 PM Joe Stringer <joe@wand.net.nz> wrote:
> >
> > On Wed, Mar 25, 2020 at 7:16 PM Andrii Nakryiko
> > <andrii.nakryiko@gmail.com> wrote:
> > >
> > > On Tue, Mar 24, 2020 at 10:58 PM Joe Stringer <joe@wand.net.nz> wrote:
> > > >
> > > > From: Lorenz Bauer <lmb@cloudflare.com>
> > > >
> > > > Attach a tc direct-action classifier to lo in a fresh network
> > > > namespace, and rewrite all connection attempts to localhost:4321
> > > > to localhost:1234 (for port tests) and connections to unreachable
> > > > IPv4/IPv6 IPs to the local socket (for address tests).
> > > >
> > > > Keep in mind that both client to server and server to client traffic
> > > > passes the classifier.
> > > >
> > > > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> > > > Co-authored-by: Joe Stringer <joe@wand.net.nz>
> > > > Signed-off-by: Joe Stringer <joe@wand.net.nz>
> > > > ---
> >
> > <snip>
> >
> > > > +static void handle_timeout(int signum)
> > > > +{
> > > > +       if (signum == SIGALRM)
> > > > +               fprintf(stderr, "Timed out while connecting to server\n");
> > > > +       kill(0, SIGKILL);
> > > > +}
> > > > +
> > > > +static struct sigaction timeout_action = {
> > > > +       .sa_handler = handle_timeout,
> > > > +};
> > > > +
> > > > +static int connect_to_server(const struct sockaddr *addr, socklen_t len)
> > > > +{
> > > > +       int fd = -1;
> > > > +
> > > > +       fd = socket(addr->sa_family, SOCK_STREAM, 0);
> > > > +       if (CHECK_FAIL(fd == -1))
> > > > +               goto out;
> > > > +       if (CHECK_FAIL(sigaction(SIGALRM, &timeout_action, NULL)))
> > > > +               goto out;
> > >
> > > no-no-no, we are not doing this. It's part of prog_tests and shouldn't
> > > install its own signal handlers and sending asynchronous signals to
> > > itself. Please find another way to have a timeout.
> >
> > I realise it didn't clean up after itself. How about signal(SIGALRM,
> > SIG_DFL); just like other existing tests do?
>
> You have alarm(3), which will deliver SIGALARM later, when other test
> is running. Once you clean up this custom signal handler it will cause
> test_progs to coredump. So still no, please find another way to do
> timeouts.

FWIW I hit this issue and alarm(0) afterwards fixed it up.

That said the SO_SNDTIMEO / SO_RCVTIMEO alternative should work fine
for this use case instead so I'll switch to that, it's marginally
cleaner.

      reply	other threads:[~2020-03-26 21:38 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25  5:57 [PATCHv2 bpf-next 0/5] Add bpf_sk_assign eBPF helper Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 1/5] bpf: Add socket assign support Joe Stringer
2020-03-26  6:23   ` Martin KaFai Lau
2020-03-26  6:31     ` Joe Stringer
2020-03-26 10:24   ` Lorenz Bauer
2020-03-26 22:52     ` Joe Stringer
2020-03-27  2:40       ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 2/5] bpf: Prefetch established socket destinations Joe Stringer
2020-03-26 21:11   ` Alexei Starovoitov
2020-03-26 21:45     ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 3/5] net: Track socket refcounts in skb_steal_sock() Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 4/5] bpf: Don't refcount LISTEN sockets in sk_assign() Joe Stringer
2020-03-25 10:29   ` Lorenz Bauer
2020-03-25 20:46     ` Joe Stringer
2020-03-26 10:20       ` Lorenz Bauer
2020-03-26 21:37         ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 5/5] selftests: bpf: add test for sk_assign Joe Stringer
2020-03-25 10:35   ` Lorenz Bauer
2020-03-25 20:55     ` Joe Stringer
2020-03-26  6:25       ` Martin KaFai Lau
2020-03-26  6:38         ` Joe Stringer
2020-03-26 23:39           ` Joe Stringer
2020-03-25 18:17   ` Yonghong Song
2020-03-25 21:20     ` Joe Stringer
2020-03-25 22:00       ` Yonghong Song
2020-03-25 23:07         ` Joe Stringer
2020-03-26 10:13     ` Lorenz Bauer
2020-03-26 21:07       ` call for bpf progs. " Alexei Starovoitov
2020-03-26 23:14         ` Yonghong Song
2020-03-27 10:02         ` Lorenz Bauer
2020-03-27 16:08           ` Alexei Starovoitov
2020-03-27 19:06         ` Joe Stringer
2020-03-27 20:16           ` Daniel Borkmann
2020-03-27 22:24             ` Alexei Starovoitov
2020-03-28  0:17           ` Andrii Nakryiko
2020-03-26  2:04   ` Andrii Nakryiko
2020-03-26  2:16   ` Andrii Nakryiko
2020-03-26  5:28     ` Joe Stringer
2020-03-26  6:31       ` Martin KaFai Lau
2020-03-26 19:36       ` Andrii Nakryiko
2020-03-26 21:38         ` Joe Stringer [this message]

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