Bug#823248: [Pkg-erlang-devel] Bug#823248: Bug#823248: erlang-base-hipe: Cannot connect to epmd when IPv6 is enabled

[Sergei Golovan]

Hi Peter,

On Mon, Nov 7, 2016 at 5:35 PM, Peter Lemenkov  wrote:
> Hello All!
>
> This might be related
>
> https://github.com/erlang/otp/pull/1129

I'm not sure about that. The original issue didn't even require BEAM
to run. The problem is that a epmd instance can't talk to the running
epmd server.

Cheers!
-- 
Sergei Golovan

Bug#823248: [Pkg-erlang-devel] Bug#823248: Bug#823248: erlang-base-hipe: Cannot connect to epmd when IPv6 is enabled

[Peter Lemenkov]

Hello All!

This might be related

https://github.com/erlang/otp/pull/1129


2016-11-07 8:30 GMT+01:00 Sergei Golovan :
> Hi Josef,
>
> Sorry for such a long delay.
>
> On Mon, May 2, 2016 at 8:32 PM, Josef Kufner  wrote:
>>
>> after upgrade to ejabberd 18.3 it won't start. I found that problem is
>> in connection to epmd, which won't accept the connection.
>>
>> Run `epmd -d` in one terminal.
>>
>> Run `strace epmd -names` in second terminal.
>>
>> The second command will get stuck when connecting to the first epmd,
>> strace says:
>>
>>   ...
>>   socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
>>   connect(3, {sa_family=AF_INET6, sin6_port=htons(4369), inet_pton(AF_INET6, 
>> "::1", _addr), sin6_flowinfo=0, sin6_scope_id=0}, 28
>>
>> ... and nothing happens. After few minutes, connect times out and fails.
>>
>> I'm running only ejabberd 18.3, it worked fine with ejabberd 18.2 and
>> erlang of the same age.
>
> Currently, there's Erlang 19.1 in testing, and I can't reproduce this
> bug with it.
> Moreover, I can't reproduce the bug with 18.3 as well. epmd listens at both
> IPv4 and IPv6 sockets and answers the query (which comes to the IPv6 socket).
>
> Can you show your IPv6 configuration? May be I'll be able to reproduce the bug
> with the config similar to yours.
>
> Cheers!
> --
> Sergei Golovan
>
> ___
> Pkg-erlang-devel mailing list
> pkg-erlang-de...@lists.alioth.debian.org
> http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-erlang-devel



-- 
With best regards, Peter Lemenkov.

Bug#823248: [Pkg-erlang-devel] Bug#823248: erlang-base-hipe: Cannot connect to epmd when IPv6 is enabled

[Sergei Golovan]

Hi Josef,

Sorry for such a long delay.

On Mon, May 2, 2016 at 8:32 PM, Josef Kufner  wrote:
>
> after upgrade to ejabberd 18.3 it won't start. I found that problem is
> in connection to epmd, which won't accept the connection.
>
> Run `epmd -d` in one terminal.
>
> Run `strace epmd -names` in second terminal.
>
> The second command will get stuck when connecting to the first epmd,
> strace says:
>
>   ...
>   socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
>   connect(3, {sa_family=AF_INET6, sin6_port=htons(4369), inet_pton(AF_INET6, 
> "::1", _addr), sin6_flowinfo=0, sin6_scope_id=0}, 28
>
> ... and nothing happens. After few minutes, connect times out and fails.
>
> I'm running only ejabberd 18.3, it worked fine with ejabberd 18.2 and
> erlang of the same age.

Currently, there's Erlang 19.1 in testing, and I can't reproduce this
bug with it.
Moreover, I can't reproduce the bug with 18.3 as well. epmd listens at both
IPv4 and IPv6 sockets and answers the query (which comes to the IPv6 socket).

Can you show your IPv6 configuration? May be I'll be able to reproduce the bug
with the config similar to yours.

Cheers!
-- 
Sergei Golovan

Bug#823248: erlang-base-hipe: Cannot connect to epmd when IPv6 is enabled

[Josef Kufner]

Package: erlang-base-hipe
Version: 1:18.3-dfsg-1
Severity: important
Tags: ipv6

Dear Maintainer,

after upgrade to ejabberd 18.3 it won't start. I found that problem is
in connection to epmd, which won't accept the connection.

Run `epmd -d` in one terminal.

Run `strace epmd -names` in second terminal.

The second command will get stuck when connecting to the first epmd,
strace says:

  ...
  socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 

  connect(3, {sa_family=AF_INET6, sin6_port=htons(4369), inet_pton(AF_INET6, 
"::1", _addr), sin6_flowinfo=0, sin6_scope_id=0}, 28

... and nothing happens. After few minutes, connect times out and fails.

I'm running only ejabberd 18.3, it worked fine with ejabberd 18.2 and
erlang of the same age.

I disabled IPv6 using `echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6` 
and everything works again, except IPv6 connectivity (luckily I don't
have it anyway). With this workaround `strace epmd -names` says:

  ...
  socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
  connect(3, {sa_family=AF_INET6, sin6_port=htons(4369), inet_pton(AF_INET6, 
"::1", _addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EADDRNOTAVAIL 
(Cannot assign requested address)
  close(3)= 0
  socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
  connect(3, {sa_family=AF_INET, sin_port=htons(4369),
  sin_addr=inet_addr("127.0.0.1")}, 16) = 0
  write(3, "\0\1n", 3)= 3
  read(3, "\0\0\21\21", 4)= 4
  fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 4), ...}) = 0
  mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0x7f40ce13b000
  write(1, "epmd: up and running on port 436"..., 45epmd: up and running
  on port 4369 with data:) = 45
  read(3, "", 3060)   = 0
  close(3)= 0
  exit_group(0)   = ?
  +++ exited with 0 +++

So the IPv6 connect fails instantly and IPv4 connect works fine.


-- System Information:
Debian Release: stretch/sid
  APT prefers stable
  APT policy: (750, 'stable'), (700, 'unstable'), (650, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.5.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=cs_CZ.utf8, LC_CTYPE=cs_CZ.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)

Versions of packages erlang-base-hipe depends on:
ii  adduser  3.114
ii  init-system-helpers  1.31
ii  libc62.22-7
ii  libsystemd0  229-5
ii  libtinfo56.0+20160319-1
ii  procps   2:3.3.11-3
ii  zlib1g   1:1.2.8.dfsg-2+b1

Versions of packages erlang-base-hipe recommends:
ii  erlang-crypto1:18.3-dfsg-1
ii  erlang-syntax-tools  1:18.3-dfsg-1
ii  libsctp1 1.0.16+dfsg-3

Versions of packages erlang-base-hipe suggests:
pn  erlang   
pn  erlang-doc   
ii  erlang-edoc  1:18.3-dfsg-1
pn  erlang-gs
ii  erlang-manpages  1:18.3-dfsg-1
ii  erlang-tools 1:18.3-dfsg-1

-- no debconf information