From: "Krzysztof Olędzki" <ole@ans.pl>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: 2.6.34: Problem with UDP traffic on lo + poll(?)
Date: Tue, 07 Sep 2010 23:51:02 +0200 [thread overview]
Message-ID: <4C86B3C6.7040809@ans.pl> (raw)
In-Reply-To: <1283895544.2634.256.camel@edumazet-laptop>
On 2010-09-07 23:39, Eric Dumazet wrote:
> Le mardi 07 septembre 2010 à 23:28 +0200, Krzysztof Olędzki a écrit :
>
>> With the above patch I'm no longer able to reproduce the problem. Thanks!
>>
>> Tested-by: Krzysztof Piotr Oledzki<ole@ans.pl>
>>
>
> Thanks a lot !
>
>> BTW: why it takes so long to trigger this bug and it is only possible
>> over a loopback interface?
>
> Its a bit tricky : You need at least 10 sockets linked in a particular
> hash chain.
>
> To check this, you can :
>
> cat /proc/net/udp
>
> maybe you have many sockets on port 123 or 53 ?
On one affected host I have 3+7 and on the other, also affacted one, I have 3+6:
root@sowa:~# egrep -cw '(53|123):' /proc/net/udp
10
root@sowa:~# egrep -w '(53|123):' /proc/net/udp
53: 3582A8C0:0035 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 6084654 2 ffff8800cc012700 0
53: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 6084652 2 ffff8800cc010900 0
123: D683A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4911 2 ffff88012de96400 0
123: 7B85A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4910 2 ffff88012de96100 0
123: 8982A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4909 2 ffff88012de95e00 0
123: 7B82A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4908 2 ffff88012de95b00 0
123: 3582A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4907 2 ffff88012de95800 0
123: 1F7EA8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4906 2 ffff88012de95500 0
123: 0100007F:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4905 2 ffff88012de95200 0
123: 00000000:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4899 2 ffff88012de94c00 0
root@cmyk:~# egrep -cw '(53|123):' /proc/net/udp
9
root@cmyk:~# egrep -w '(53|123):' /proc/net/udp
53: A2CD1253:0035 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 3774 2 eeaa9840 0
53: 0100A8C0:0035 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 3772 2 eeaa9a40 0
53: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 3770 2 eeaa9c40 0
123: A6CD1253:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4693 2 eeacdc80 0
123: A5CD1253:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4692 2 eeaa9640 0
123: A2CD1253:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4691 2 ed201700 0
123: 0100A8C0:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4690 2 eeacd880 0
123: 0100007F:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4689 2 ec649740 0
123: 00000000:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 4683 2 ed201d00 0
But how 123 is related to 53?
> And about loopback, I have no idea... I am pretty sure I can trigger the
> bug with other interfaces.
OK. Probably it is because my other hosts have only a single IP and only
the problematic ones have both DNS server and multiple IP (many sockets).
Best regards,
Krzysztof Olędzki
next prev parent reply other threads:[~2010-09-07 21:51 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 17:11 2.6.34: Problem with UDP traffic on lo + poll(?) Krzysztof Oledzki
2010-09-06 19:42 ` Eric Dumazet
2010-09-06 19:55 ` Krzysztof Olędzki
2010-09-06 20:29 ` Eric Dumazet
2010-09-06 20:44 ` Krzysztof Olędzki
2010-09-06 20:48 ` Krzysztof Olędzki
2010-09-07 15:37 ` Krzysztof Olędzki
2010-09-07 16:36 ` Eric Dumazet
2010-09-07 19:20 ` Krzysztof Olędzki
2010-09-07 19:26 ` Eric Dumazet
2010-09-07 19:59 ` David Miller
2010-09-07 21:35 ` [PATCH] inet: dont set inet_rcv_saddr in connect() Eric Dumazet
2010-09-07 21:52 ` Krzysztof Olędzki
2010-09-08 2:16 ` David Miller
2010-09-08 4:13 ` Eric Dumazet
2010-09-08 2:34 ` Brian Haley
2010-09-08 3:34 ` David Miller
2010-09-08 4:42 ` Eric Dumazet
2010-09-08 5:51 ` David Miller
2010-09-08 4:57 ` Eric Dumazet
2010-09-08 5:36 ` David Miller
2010-09-08 5:52 ` Eric Dumazet
2010-09-08 10:10 ` [PATCH] udp: add rehash on connect() Eric Dumazet
2010-09-08 15:06 ` Krzysztof Olędzki
2010-09-08 15:17 ` Eric Dumazet
2010-09-08 15:29 ` Krzysztof Olędzki
2010-09-08 15:08 ` [PATCH v2] " Eric Dumazet
2010-09-08 16:52 ` Krzysztof Olędzki
2010-09-09 4:39 ` David Miller
2010-09-08 14:27 ` [PATCH] inet: dont set inet_rcv_saddr in connect() Eric Dumazet
2010-09-07 21:28 ` 2.6.34: Problem with UDP traffic on lo + poll(?) Krzysztof Olędzki
2010-09-07 21:39 ` Eric Dumazet
2010-09-07 21:51 ` Krzysztof Olędzki [this message]
2010-09-08 4:12 ` Eric Dumazet
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