From: Laura Abbott <labbott@redhat.com>
To: "David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Patrick McHardy <kaber@trash.net>,
Sam Kumar <samanthakumar@google.com>,
Willem de Bruijn <willemb@google.com>
Cc: netdev <netdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [REGRESSION] Select hang with zero sized UDP packets
Date: Tue, 23 Aug 2016 10:53:26 -0700 [thread overview]
Message-ID: <08d225a8-e98f-c0c6-271d-acc2584347fc@redhat.com> (raw)
Hi,
Fedora received a report[1] of a unit test failing on Ruby when using the
4.7 kernel. This was a test to send a zero sized UDP packet. With the
4.7 kernel, the test now timing out on a select instead of completing.
The reduced ruby test is
def test_udp_recvfrom_nonblock
u1 = UDPSocket.new
u2 = UDPSocket.new
u1.bind("127.0.0.1", 0)
u2.send("", 0, u1.getsockname)
IO.select [u1] # test gets stuck here
ensure
u1.close if u1
u2.close if u2
end
which roughly corresponds to this in C
int main()
{
int fd1, fd2;
struct sockaddr_in addr1;
unsigned int len1;
int ret;
fd_set rfds;
fd1 = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, IPPROTO_UDP);
fd2 = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, IPPROTO_UDP);
if (fd1 < 0 || fd2 < 0) {
printf("socket fail");
exit(1);
}
len1 = sizeof(addr1);
memset(&addr1, 0, sizeof(addr1));
addr1.sin_family = AF_INET;
addr1.sin_addr.s_addr = inet_addr("127.0.0.1");
addr1.sin_port = htons(0);
ret = bind(fd1, (struct sockaddr *)&addr1, len1);
if (ret < 0) {
printf("fu %d\n", errno);
exit(1);
}
ret = getsockname(fd1, (struct sockaddr *)&addr1, &len1);
if (ret < 0) {
printf("getsockname failed %d\n", errno);
exit(1);
}
ret = sendto(fd2, "", 0, 0, (struct sockaddr *)&addr1, len1);
if (ret < 0) {
printf("sendto failed %d\n", errno);
exit(1);
}
FD_ZERO(&rfds);
FD_SET(fd1, &rfds);
// hang here
select(fd1+1, &rfds, NULL, NULL, NULL);
}
Bisection showed
commit e6afc8ace6dd5cef5e812f26c72579da8806f5ac
Author: samanthakumar <samanthakumar@google.com>
Date: Tue Apr 5 12:41:15 2016 -0400
udp: remove headers from UDP packets before queueing
Remove UDP transport headers before queueing packets for reception.
This change simplifies a follow-up patch to add MSG_PEEK support.
Signed-off-by: Sam Kumar <samanthakumar@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As the offending commit. The issue is still reproducible on master
as of this morning and I don't see anything explicitly tagged in
net-next as fixing this.
Any ideas?
Thanks,
Laura
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1365940
next reply other threads:[~2016-08-23 17:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 17:53 Laura Abbott [this message]
2016-08-23 18:25 ` [REGRESSION] Select hang with zero sized UDP packets David Miller
2016-08-23 19:03 ` Eric Dumazet
2016-08-23 20:06 ` Laura Abbott
2016-08-23 20:42 ` Eric Dumazet
2016-08-23 20:53 ` [PATCH net] udp: fix poll() issue with zero sized packets Eric Dumazet
2016-08-23 20:56 ` Eric Dumazet
2016-08-23 20:59 ` [PATCH v2 " Eric Dumazet
2016-08-23 23:39 ` David Miller
2016-08-24 8:22 ` [REGRESSION] Select hang with zero sized UDP packets Dan Akunis
2016-08-24 13:02 ` Eric Dumazet
2016-08-24 13:42 ` One Thousand Gnomes
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