From: Ding Tianhong <dingtianhong@huawei•com>
To: David Miller <davem@davemloft•net>
Cc: <fubar@us•ibm.com>, <andy@greyhouse•net>, <vfalico@redhat•com>,
<cwang@twopensource•com>, <thomas@glanzmann•de>,
<jiri@resnulli•us>, <edumazet@google•com>,
<sfeldma@cumulusnetworks•com>, <netdev@vger•kernel.org>
Subject: Re: [PATCH net-next] bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for 802.3ad mode
Date: Wed, 19 Feb 2014 10:13:22 +0800 [thread overview]
Message-ID: <53041342.90508@huawei.com> (raw)
In-Reply-To: <20140218.173812.1179657046277970562.davem@davemloft.net>
On 2014/2/19 6:38, David Miller wrote:
> From: Ding Tianhong <dingtianhong@huawei•com>
> Date: Tue, 18 Feb 2014 19:25:06 +0800
>
>> The problem was introduced by the commit 1d3ee88ae0d
>> (bonding: add netlink attributes to slave link dev).
>> The bond_set_active_slave() and bond_set_backup_slave()
>> will use rtmsg_ifinfo to send slave's states, so these
>> two functions should be called in RTNL.
>>
>> In 802.3ad mode, acquiring RTNL for the __enable_port and
>> __disable_port cases is difficult, as those calls generally
>> already hold the state machine lock, and cannot unconditionally
>> call rtnl_lock because either they already hold RTNL (for calls
>> via bond_3ad_unbind_slave) or due to the potential for deadlock
>> with bond_3ad_adapter_speed_changed, bond_3ad_adapter_duplex_changed,
>> bond_3ad_link_change, or bond_3ad_update_lacp_rate. All four of
>> those are called with RTNL held, and acquire the state machine lock
>> second. The calling contexts for __enable_port and __disable_port
>> already hold the state machine lock, and may or may not need RTNL.
>>
>> According to the Jay's opinion, I don't think it is a problem that
>> the slave don't send notify message synchronously when the status
>> changed, normally the state machine is running every 100 ms, send
>> the notify message at the end of the state machine if the slave's
>> state changed should be better.
>>
>> I fix the problem through these steps:
>>
>> 1). add a new function bond_set_slave_state() which could change
>> the slave's state and call rtmsg_ifinfo() according to the input
>> parameters called notify.
>>
>> 2). Add a new slave parameter which called should_notify, if the slave's state
>> changed and don't notify yet, the parameter will be set to 1, and then if
>> the slave's state changed again, the param will be set to 0, it indicate that
>> the slave's state has been restored, no need to notify any one.
>>
>> 3). the __enable_port and __disable_port should not call rtmsg_ifinfo
>> in the state machine lock, any change in the state of slave could
>> set a flag in the slave, it will indicated that an rtmsg_ifinfo
>> should be called at the end of the state machine.
>>
>> Cc: Jay Vosburgh <fubar@us•ibm.com>
>> Cc: Veaceslav Falico <vfalico@redhat•com>
>> Cc: Andy Gospodarek <andy@greyhouse•net>
>> Signed-off-by: Ding Tianhong <dingtianhong@huawei•com>
>
> This seems more appropriately targetted at 'net' since it's a real
> bug fix, do you agree?
>
> .
>
Agree.
Ding
next prev parent reply other threads:[~2014-02-19 2:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-18 11:25 [PATCH net-next] bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for 802.3ad mode Ding Tianhong
2014-02-18 11:49 ` Nikolay Aleksandrov
2014-02-18 11:53 ` Nikolay Aleksandrov
2014-02-18 12:14 ` Thomas Glanzmann
2014-02-18 12:16 ` Ding Tianhong
2014-02-18 22:38 ` David Miller
2014-02-19 2:13 ` Ding Tianhong [this message]
2014-02-18 23:18 ` Jay Vosburgh
2014-02-19 2:26 ` Ding Tianhong
2014-02-21 3:38 ` Scott Feldman
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