From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: Query on a lockdep issue in neigh_lookup
Date: Wed, 14 Sep 2011 01:59:08 +0200
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To: Murali raja Muniraju <murali.rajam@gmail.com>
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Le mardi 13 septembre 2011 =C3=A0 16:11 -0700, Murali raja Muniraju a =C3=
=A9crit :
> Hi,
>    I see a potential deadlock situation on the kernel 2.6.34. Has thi=
s
> been fixed in the later version of the kernel.
>=20
> I see that one after holding the neigh_lookup, one can acquire the
> lock for rt_hash_locks
>=20
> But there is a situation while freed skb's in dst_release while
> holding the rt_hash_locks, neigh_lookup can be called which tries to
> acquire its lock.
>=20
> This seems to be a deadlock candidate.
>=20
> Thanks,
> Murali
>=20
> Below if the scenario found by lockdep on a debug kernel during the
> kernel bootup.
>=20

All this code changed in 2.6.37 with commit
d6bf781712a1d25cc8987036b3a48535b331eb91
(net neigh: RCU conversion of neigh hash table)