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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: "sunyucong@gmail.com" <sunyucong@gmail.com>,
	Jiang Wang <jiang.wang@bytedance.com>,
	Cong Wang <cong.wang@bytedance.com>
Cc: Yucong Sun <fallentree@fb.com>,
	Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next] selftests/bpf: reduce more flakyness in sockmap_listen
Date: Thu, 26 Aug 2021 12:07:46 -0700	[thread overview]
Message-ID: <CAADnVQJB3GKKr1hMWHNKYhoo8CzrDQ83LEnO8c+ntOBtEkjApA@mail.gmail.com> (raw)
In-Reply-To: <CAJygYd3M1E3N9C02WCmPD6_i9miXaCe=OP-M32QTnOXOajBPZA@mail.gmail.com>

On Thu, Aug 26, 2021 at 11:18 AM sunyucong@gmail.com
<sunyucong@gmail.com> wrote:
>
> Reporting back: I tried a select() based approach, (as attached below)
>  but unfortunately it doesn't seem to work. During testing,  I am
> always getting full timeout errors as the socket never seems to become
> ready to read(). My guess is that this has something to do with the
> sockets being created through sockpair() , but I am unable to confirm.
>
> On the other hand, the previous patch approach works perfectly fine, I
> would still like to request to apply that instead.

Ok. Applied your earlier patch, but it's a short term workaround.
select() should work for af_unix.
I suspect something got broken with the redirect.
Cong, Jiang,
could you please take a look ?

>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> index 5c5979046523..247e8b7a6911 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> @@ -949,7 +949,6 @@ static void redir_to_connected(int family, int
> sotype, int sock_mapfd,
>         int err, n;
>         u32 key;
>         char b;
> -       int retries = 100;
>
>         zero_verdict_count(verd_mapfd);
>
> @@ -1002,15 +1001,12 @@ static void redir_to_connected(int family, int
> sotype, int sock_mapfd,
>                 goto close_peer1;
>         if (pass != 1)
>                 FAIL("%s: want pass count 1, have %d", log_prefix, pass);
> -again:
> +
> +       if (poll_read(c0, IO_TIMEOUT_SEC))
> +             FAIL_ERRNO("%s: read", log_prefix);
>         n = read(c0, &b, 1);
> -       if (n < 0) {
> -               if (errno == EAGAIN && retries--) {
> -                       usleep(1000);
> -                       goto again;
> -               }
> +       if (n < 0)
>                 FAIL_ERRNO("%s: read", log_prefix);
> -       }
>         if (n == 0)
>                 FAIL("%s: incomplete read", log_prefix);
>
> @@ -1571,7 +1567,6 @@ static void unix_redir_to_connected(int sotype,
> int sock_mapfd,
>         const char *log_prefix = redir_mode_str(mode);
>         int c0, c1, p0, p1;
>         unsigned int pass;
> -       int retries = 100;
>         int err, n;
>         int sfd[2];
>         u32 key;
> @@ -1606,15 +1601,11 @@ static void unix_redir_to_connected(int
> sotype, int sock_mapfd,
>         if (pass != 1)
>                 FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>
> -again:
> +       if (poll_read(mode == REDIR_INGRESS ? p0 : c0, IO_TIMEOUT_SEC))
> +             FAIL_ERRNO("%s: read", log_prefix);
>         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> -       if (n < 0) {
> -               if (errno == EAGAIN && retries--) {
> -                       usleep(1000);
> -                       goto again;
> -               }
> +       if (n < 0)
>                 FAIL_ERRNO("%s: read", log_prefix);
> -       }
>         if (n == 0)
>                 FAIL("%s: incomplete read", log_prefix);
>
> @@ -1748,7 +1739,6 @@ static void udp_redir_to_connected(int family,
> int sock_mapfd, int verd_mapfd,
>         const char *log_prefix = redir_mode_str(mode);
>         int c0, c1, p0, p1;
>         unsigned int pass;
> -       int retries = 100;
>         int err, n;
>         u32 key;
>         char b;
> @@ -1781,15 +1771,11 @@ static void udp_redir_to_connected(int family,
> int sock_mapfd, int verd_mapfd,
>         if (pass != 1)
>                 FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>
> -again:
> +       if (poll_read(mode == REDIR_INGRESS ? p0 : c0, IO_TIMEOUT_SEC * 10))
> +               FAIL_ERRNO("%s: read", log_prefix);
>         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> -       if (n < 0) {
> -               if (errno == EAGAIN && retries--) {
> -                       usleep(1000);
> -                       goto again;
> -               }
> +       if (n < 0)
>                 FAIL_ERRNO("%s: read", log_prefix);
> -       }
>         if (n == 0)
>                 FAIL("%s: incomplete read", log_prefix);
>
> @@ -1841,7 +1827,6 @@ static void inet_unix_redir_to_connected(int
> family, int type, int sock_mapfd,
>         const char *log_prefix = redir_mode_str(mode);
>         int c0, c1, p0, p1;
>         unsigned int pass;
> -       int retries = 100;
>         int err, n;
>         int sfd[2];
>         u32 key;
> @@ -1876,15 +1861,11 @@ static void inet_unix_redir_to_connected(int
> family, int type, int sock_mapfd,
>         if (pass != 1)
>                 FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>
> -again:
> +       if (poll_read(mode == REDIR_INGRESS ? p0 : c0, IO_TIMEOUT_SEC))
> +             FAIL_ERRNO("%s: read", log_prefix);
>         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> -       if (n < 0) {
> -               if (errno == EAGAIN && retries--) {
> -                       usleep(1000);
> -                       goto again;
> -               }
> +       if (n < 0)
>                 FAIL_ERRNO("%s: read", log_prefix);
> -       }
>         if (n == 0)
>                 FAIL("%s: incomplete read", log_prefix);
>
> @@ -1932,7 +1913,6 @@ static void unix_inet_redir_to_connected(int
> family, int type, int sock_mapfd,
>         int sfd[2];
>         u32 key;
>         char b;
> -       int retries = 100;
>
>         zero_verdict_count(verd_mapfd);
>
> @@ -1963,15 +1943,11 @@ static void unix_inet_redir_to_connected(int
> family, int type, int sock_mapfd,
>         if (pass != 1)
>                 FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>
> -again:
> +       if (poll_read(mode == REDIR_INGRESS ? p0 : c0, IO_TIMEOUT_SEC))
> +             FAIL_ERRNO("%s: read", log_prefix);
>         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> -       if (n < 0) {
> -               if (errno == EAGAIN && retries--) {
> -                       usleep(1000);
> -                       goto again;
> -               }
> +       if (n < 0)
>                 FAIL_ERRNO("%s: read", log_prefix);
> -       }
>         if (n == 0)
>                 FAIL("%s: incomplete read", log_prefix);

  reply	other threads:[~2021-08-26 19:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-25 18:47 [PATCH bpf-next] selftests/bpf: reduce more flakyness in sockmap_listen Yucong Sun
2021-08-26  1:04 ` Alexei Starovoitov
2021-08-26  2:37   ` sunyucong
2021-08-26 18:18     ` sunyucong
2021-08-26 19:07       ` Alexei Starovoitov [this message]
2021-08-26 19:23         ` sunyucong
2021-08-26 21:05           ` Alexei Starovoitov
2021-08-26 21:07             ` sunyucong
2021-08-31 19:33         ` Cong Wang
2021-09-02  1:33           ` Cong Wang
2021-09-02  3:34             ` sunyucong
2021-09-03 23:44               ` Cong Wang
2021-09-07  2:24                 ` sunyucong
2021-09-15 14:13                   ` sunyucong
2021-09-15 16:54                   ` Cong Wang

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