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From: "Linus Lüssing" <linus.luessing-djzkFPsfvsizQB+pC5nmwQ@public.gmane.org>
To: netfilter-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org
Subject: Re: "Kernel bug detected [...] nf_ct_del_from_dying_or_unconfirmed_list"
Date: Tue, 29 Jan 2019 10:07:54 +0100	[thread overview]
Message-ID: <20190129090754.GB1528@otheros> (raw)
In-Reply-To: <20190127214708.GC1788@otheros>

On Sun, Jan 27, 2019 at 10:47:08PM +0100, Linus Lüssing wrote:
[...]
> The crash itself is triggered by the:
> 
>   BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
> 
> in here:
> 
> https://elixir.bootlin.com/linux/v4.9.146/source/net/netfilter/nf_conntrack_core.c#L354

I had tried the nf_reset()s and Wang's patch but with no success.

Skimming through the code I noticed that there aren't that many
opportunities for the hnnode to become zero. There are several
hlist_nulls_del_rcu(), but no hlist_nulls_del_init_rcu()s for
instance.

That started to make me wonder whether something from "outside"
might be setting the hnnode to zero - and yeah...

I missed that batadv_send_skb_unicast() always frees/consumes the
skb... and I was freeing the skb myself if that call returned
!NET_XMIT_SUCCESS. So a double kfree_skb()... I'm a bit surprised
that things did not crash more often...

Sorry for the noise :-(. But thanks for all the help and quick
responses!

      parent reply	other threads:[~2019-01-29  9:07 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-27 21:47 "Kernel bug detected [...] nf_ct_del_from_dying_or_unconfirmed_list" Linus Lüssing
2019-01-27 22:48 ` Florian Westphal
     [not found]   ` <20190127224822.lsagihtfiuvxyool-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>
2019-01-28 13:35     ` Chieh-Min Wang
     [not found]       ` <CALJUYjOq-xpjorsfnMRthzmC+iuDTVOPHXRb2p3ahU248Jrw4w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-01-28 13:39         ` Florian Westphal
     [not found]           ` <20190128133940.jxwuscyi2wvbfb52-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>
2019-01-28 13:50             ` Pablo Neira Ayuso
2019-01-28 14:01               ` Florian Westphal
2019-01-28 14:03               ` Chieh-Min Wang
     [not found]                 ` <CALJUYjO4=pDT0COGJRx2YWDMiEJTpa2CdqQqxndd93khVDZHjA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-01-28 14:13                   ` Florian Westphal
     [not found]                     ` <20190128141317.pxq7vklx346bv2bu-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>
2019-01-28 14:16                       ` Chieh-Min Wang
     [not found]                         ` <CALJUYjMM7EJVxxhh_q=607yn7OXhfnhrnk+m=tQ7C8GJjOCDcA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-01-28 14:25                           ` Chieh-Min Wang
2019-01-29  9:07 ` Linus Lüssing [this message]

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