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Message-ID: <49AC597B.4090404@candelatech.com>
Date: Mon, 02 Mar 2009 14:11:07 -0800
From: Ben Greear <greearb@...delatech.com>
To: Stephen Hemminger <shemminger@...tta.com>
CC: "Eric W. Biederman" <ebiederm@...ssion.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Patrick McHardy <kaber@...sh.net>,
Linux Netdev List <netdev@...r.kernel.org>,
"David S. Miller" <davem@...emloft.net>
Subject: Re: IPv4/IPv6 sysctl unregistration deadlock
Stephen Hemminger wrote:
> On Fri, 27 Feb 2009 10:26:43 -0800
> Ben Greear <greearb@...delatech.com> wrote:
>
>> Stephen Hemminger wrote:
>>
>>> Subject: [PATCH] Avoid race between network down and sysfs
>>>
>>>
>>> Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
>>>
>>> --- a/net/core/net-sysfs.c 2009-02-26 08:36:18.000000000 -0800
>>> +++ b/net/core/net-sysfs.c 2009-02-26 08:37:51.000000000 -0800
>>> @@ -77,7 +77,9 @@ static ssize_t netdev_store(struct devic
>>> if (endp == buf)
>>> goto err;
>>>
>>> - rtnl_lock();
>>> + if (!rtnl_trylock())
>>> + return -ERESTARTSYS;
>>> +
>>> if (dev_isalive(net)) {
>>> if ((ret = (*set)(net, new)) == 0)
>>> ret = len;
>> I can test this to see if it fixes my problem. Are the above lines the
>> entirety of the patch?
>
> yes
With both of Stephen's patches included in the latest -rc6 source,
I re-ran the test and it seems to be working (I added printks so
that I would know the new code was being exercised)
I had 2000 or so mac-vlans configured, with 10 of them being
re-configured concurrently, while also deleting groups of 20-100
mac-vlans in my test. This was locking up reliably before,
and now it seems to be working fine.
Here's the kernel log showing the ERESTARTSYS in action. I don't
have an easy way to check to see if the VFS (or whatever) retried
the call properly, but will let you all know if I see any indication
that isn't working.
I only saw the ipv6 fixup in my logs, but maybe my test case just
doesn't hit the other...
Mar 2 13:37:41 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:37:41 simech-1 kernel: ADDRCONF(NETDEV_UP): eth1: link is not ready
Mar 2 13:37:42 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:38:13 simech-1 kernel:last message repeated 42 times
Mar 2 13:39:20 simech-1 kernel:last message repeated 71 times
Mar 2 13:40:13 simech-1 kernel:last message repeated 68 times
Mar 2 13:40:13 simech-1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 8
Mar 2 13:40:13 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:40:21 simech-1 kernel:last message repeated 11 times
Mar 2 13:40:21 simech-1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 13
Mar 2 13:40:21 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:40:28 simech-1 kernel:last message repeated 16 times
Mar 2 13:40:28 simech-1 kernel: __ratelimit: 3352 callbacks suppressed
Mar 2 13:40:28 simech-1 kernel: Neighbour table overflow.
Mar 2 13:40:28 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:40:34 simech-1 kernel:last message repeated 8 times
Mar 2 13:40:34 simech-1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 20
Mar 2 13:40:34 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:40:54 simech-1 kernel:last message repeated 42 times
Mar 2 13:40:54 simech-1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 7
Mar 2 13:40:54 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:01 simech-1 kernel:last message repeated 13 times
Mar 2 13:41:01 simech-1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 13
Mar 2 13:41:01 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:14 simech-1 kernel:last message repeated 26 times
Mar 2 13:41:14 simech-1 dhclient: No DHCPOFFERS received.
Mar 2 13:41:14 simech-1 dhclient: No working leases in persistent database - sleeping.
Mar 2 13:41:15 simech-1 dhclient: receive_packet failed on eth1: Network is down
Mar 2 13:41:16 simech-1 kernel: ADDRCONF(NETDEV_UP): eth1: link is not ready
Mar 2 13:41:17 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:24 simech-1 kernel:last message repeated 16 times
Mar 2 13:41:24 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:25 simech-1 kernel:last message repeated 8 times
Mar 2 13:41:25 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:30 simech-1 kernel:last message repeated 11 times
Mar 2 13:41:30 simech-1 kernel: __ratelimit: 7059 callbacks suppressed
Mar 2 13:41:30 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:30 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:30 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:35 simech-1 kernel:last message repeated 10 times
Mar 2 13:41:35 simech-1 kernel: __ratelimit: 7973 callbacks suppressed
Mar 2 13:41:35 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:36 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:36 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:40 simech-1 kernel:last message repeated 7 times
Mar 2 13:41:40 simech-1 kernel: __ratelimit: 10890 callbacks suppressed
Mar 2 13:41:40 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:40 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:40 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:46 simech-1 kernel:last message repeated 13 times
Mar 2 13:41:46 simech-1 kernel: __ratelimit: 6571 callbacks suppressed
Mar 2 13:41:46 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:46 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:46 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:51 simech-1 kernel:last message repeated 7 times
Mar 2 13:41:51 simech-1 kernel: __ratelimit: 15491 callbacks suppressed
Mar 2 13:41:51 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:51 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:51 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:41:56 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:56 simech-1 kernel: __ratelimit: 9658 callbacks suppressed
Mar 2 13:41:56 simech-1 kernel: Neighbour table overflow.
Mar 2 13:41:56 simech-1 kernel:last message repeated 9 times
Mar 2 13:41:56 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:42:01 simech-1 kernel:last message repeated 10 times
Mar 2 13:42:01 simech-1 kernel: __ratelimit: 12678 callbacks suppressed
Mar 2 13:42:01 simech-1 kernel: Neighbour table overflow.
Mar 2 13:42:01 simech-1 kernel:last message repeated 9 times
Mar 2 13:42:01 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:42:06 simech-1 kernel:last message repeated 7 times
Mar 2 13:42:06 simech-1 kernel: __ratelimit: 13401 callbacks suppressed
Mar 2 13:42:06 simech-1 kernel: Neighbour table overflow.
Mar 2 13:42:06 simech-1 kernel:last message repeated 9 times
Mar 2 13:42:06 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:42:11 simech-1 kernel:last message repeated 10 times
Mar 2 13:42:11 simech-1 kernel: __ratelimit: 11875 callbacks suppressed
Mar 2 13:42:11 simech-1 kernel: Neighbour table overflow.
Mar 2 13:42:11 simech-1 kernel:last message repeated 9 times
Mar 2 13:42:11 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Mar 2 13:42:16 simech-1 kernel:last message repeated 9 times
Mar 2 13:42:16 simech-1 kernel: __ratelimit: 9362 callbacks suppressed
Mar 2 13:42:16 simech-1 kernel: Neighbour table overflow.
Mar 2 13:42:17 simech-1 kernel:last message repeated 9 times
Mar 2 13:42:17 simech-1 kernel: Returning ERESTARTSYS in ipv6-addrconf-fixup-forwarding to avoid deadlock.
Thanks,
Ben
--
Ben Greear <greearb@...delatech.com>
Candela Technologies Inc http://www.candelatech.com
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