From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Maciej Żenczykowski" <zenczykowski@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, MuraliRaja Muniraju <muralira@google.com>
Subject: Re: [PATCH] net: fix lockdep issue in __neigh_event_send
Date: Mon, 19 Sep 2011 23:03:27 +0200 [thread overview]
Message-ID: <1316466207.2455.15.camel@edumazet-laptop> (raw)
In-Reply-To: <1316465182.2455.10.camel@edumazet-laptop>
Le lundi 19 septembre 2011 à 22:46 +0200, Eric Dumazet a écrit :
> Le lundi 19 septembre 2011 à 13:39 -0700, Maciej Żenczykowski a écrit :
> > [ 90.544012] the existing dependency chain (in reverse order) is:
> > [ 90.544012]
> > [ 90.544012] -> #2 (&(&rt_hash_locks[i])->rlock){+.-...}:
> > [ 90.544012] [<ffffffff810a4910>] __lock_acquire+0xb3b/0xcda
> > [ 90.544012] [<ffffffff810a4b72>] lock_acquire+0xc3/0xe9
> > [ 90.544012] [<ffffffff81430d66>] _raw_spin_lock_bh+0x36/0x45
> > [ 90.544012] [<ffffffff813d9659>] rt_dst_release+0x4a/0x8d
rt_dst_release() again...
> > [ 90.544012] [<ffffffff813bee34>] dst_release+0x5d/0x66
> > [ 90.544012] [<ffffffff813af24e>] skb_release_head_state+0x1f/0xa5
> > [ 90.544012] [<ffffffff813aefec>] __kfree_skb+0x16/0x87
> > [ 90.544012] [<ffffffff813af101>] kfree_skb+0x72/0x7a
> > [ 90.544012] [<ffffffff813c06f9>] __neigh_event_send+0x126/0x176
> >
> Hmm
>
> What exact kernel version is it ?
>
>
Just to say what I already said to Murali raja Muniraju one week ago :
To my knowledge, no linux pristine linux kernel has this bug.
dst_release() is lockless.
So could you explain why its so important we add this 'bugfix' if it
only applies to a Google kernel ?
Anything I missed from my previous analysis ?
Thanks !
next prev parent reply other threads:[~2011-09-19 21:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-19 19:12 [PATCH] net: fix lockdep issue in __neigh_event_send Maciej Żenczykowski
2011-09-19 19:42 ` Eric Dumazet
2011-09-19 20:39 ` Maciej Żenczykowski
2011-09-19 20:46 ` Eric Dumazet
2011-09-19 21:03 ` Eric Dumazet [this message]
2011-09-20 0:01 ` Maciej Żenczykowski
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