Re: [PATCH][SCTP] Re: lockdep: inconsistent lock state ipv6_add_addr/sctp_v6_copy_addrlist (2.6.21-rc1)

From: Herbert Xu
Date: Thu Mar 08 2007 - 06:02:47 EST


Jarek Poplawski <jarkao2@xxxxx> wrote:
> On 25-02-2007 10:08, Simon Arlott wrote:
>> This happens on every boot if more information is needed:
>>
>> [ 37.393715] =================================
>> [ 37.393830] [ INFO: inconsistent lock state ]
>> [ 37.393881] 2.6.21-rc1-git #146
>> [ 37.393929] ---------------------------------
>> [ 37.393979] inconsistent {softirq-on-R} -> {in-softirq-W} usage.
>> [ 37.394040] hotplug/1072 [HC0[0]:SC1[2]:HE1:SE0] takes:
>> [ 37.394092] (&ndev->lock){-+-?}, at: [<b04a7944>] ipv6_add_addr+0x164/0x1e0
>> [ 37.394308] {softirq-on-R} state was registered at:
>> [ 37.394359] [<b013fc42>] __lock_acquire+0x622/0xbb0
>> [ 37.394515] [<b0140652>] lock_acquire+0x62/0x80
>> [ 37.394678] [<b0511c65>] _read_lock+0x35/0x50
>> [ 37.394834] [<b050e200>] sctp_v6_copy_addrlist+0x30/0xc0
> ...
>
> [SCTP] ipv6: inconsistent lock state ipv6_add_addr/sctp_v6_copy_addrlist
>
> lockdep found that dev->lock taken from softirq in ipv6_add_addr
> is also taken in sctp_v6_copy_addrlist with softirqs enabled, so
> lockup is possible.

Who's calling ipv6_add_addr from softirq context? That's got to be
wrong because ipv6_add_addr requires the RTNL.

Cheers,
--
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Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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