Subject: Re: BUG: ping without route segfaults in dst_release

From: Marc Kleine-Budde <[email-masked]>
Date: Tue, 29 Mar 2011 02:00:35 +0200

On 03/29/2011 01:51 AM, David Miller wrote:
> From: Marc Kleine-Budde <[email-masked]>
> Date: Tue, 29 Mar 2011 01:18:48 +0200
> 
>> root@ptx:~ ping 130.75.1.32
>> PING 130.75.1.32 (130.75[   10.160000] Unable to handle kernel paging request at virtual address ffffffdb
> 
> Well, that was easy enough :-)

..just finished bisecting :)

FWIW:

b23dd4fe42b455af5c6e20966b7d6959fa8352ea is the first bad commit
commit b23dd4fe42b455af5c6e20966b7d6959fa8352ea
Author: David S. Miller <[email-masked]>
Date:   Wed Mar 2 14:31:35 2011 -0800

    ipv4: Make output route lookup return rtable directly.

    Instead of on the stack.

    Signed-off-by: David S. Miller <[email-masked]>

:040000 040000 a30b2e32bbbbed71fe97ba44b8e0ac4d8691232b 589f843359ccb53c7800e594ea5efa074413f22e M      drivers
:040000 040000 001c629e354ff875e8f2d3d7e4df2506f3396448 a55b417b1c10c3f23fafdf9fa5c6ab3c132d5223 M      include
:040000 040000 1a0100ddadb50d9e61b66d1f18f47f25a4866856 4e89411fcefcfb87f8973910a97b4776d7a3f7f1 M      net

> 
> --------------------
> ipv4: Don't ip_rt_put() an error pointer in RAW sockets.
> 
> Reported-by: Marc Kleine-Budde <[email-masked]>
> Signed-off-by: David S. Miller <[email-masked]>
> ---
>  net/ipv4/raw.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> index e837ffd..2d3c72e 100644
> --- a/net/ipv4/raw.c
> +++ b/net/ipv4/raw.c
> @@ -569,6 +569,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
>  		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
>  		if (IS_ERR(rt)) {
>  			err = PTR_ERR(rt);
> +			rt = NULL;

IIRC I saw another commit which looks the same, in a different file
though. Any chance there are more rt = NULL missing?
>  			goto done;
>  		}
>  	}

Marc

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