Re: 2.6.39-rc: WARNING: at __ip_select_ident+0xd3/0xf0()

[Alexander Beregalov <a.beregalov@gmail.com>]

> Thanks Alexander for this bug report.
>
> Here is a patch to fix this issue (and other crash you mentioned in next
> mail)
>
Hi Eric,
Thank you for the fix, have not it checked however.

I did not know that the second problem
(https://lkml.org/lkml/2011/3/23/38) had the same reason.
I did not notice inetpeer_free_rcu() in its calltrace.

Thanks for that.
>
> [PATCH] ipv4: fix ip_rt_update_pmtu()
>
> commit 2c8cec5c10bc (Cache learned PMTU information in inetpeer) added
> an extra inet_putpeer() call in ip_rt_update_pmtu().
>
> This results in various problems, since we can free one inetpeer, while
> it is still in use.
>
> Ref: http://www.spinics.net/lists/netdev/msg159121.html
>
> Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> ---
>  net/ipv4/route.c |    2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 870b518..34921b0 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -1593,8 +1593,6 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
>                        rt->rt_peer_genid = rt_peer_genid();
>                }
>                check_peer_pmtu(dst, peer);
> -
> -               inet_putpeer(peer);
>        }
>  }
>
>
>
>