Re: [mpls-linux-devel] Kernel taint in function mpls_out_op_set

[Renato W. <ren...@gm...>]

Hello Igor,

Firstly, the main goal of this project now is to merge into the
upstream kernel. Jorge is putting a lot of effort to port the MPLS
code to net-next, clean-up the code, improve the performance, etc.
Therefore, I think you should concentrate your efforts into his
repository.

We also have interest in maintaining stable branches for older LTS
kernels. In this case, please provide patches against the official
mpls-linux repositories.

Finally, thank you for the patches, your help is very welcome.

Best Regards,
Renato.

2011/8/18 Igor Maravić <ig...@et...>:
> Whomever it might concern:
> Kernel taint was occurring in function mpls_out_op_set in file
> mpls_opcode.c. That was occurring because, __refcnt of skb's dst_ops was
> negative after release. Because of that, skb's dst_ops should be incremented
> with function dst_hold, before it is released with dst_release. This is my
> solution for the function:
> MPLS_OUT_OPCODE_PROTOTYPE(mpls_out_op_set)
> {
> struct mpls_dst *md = data;
> MPLS_ENTER;
> /* Release the current dst in the socket buffer */
> if (skb_dst(*skb)) {
> dst_hold(skb_dst(*skb)); //added this to avoid kernel taint: Igor Maravić
> <ig...@et...>
> skb_dst_drop(*skb);
> }
> /*
> * Update the dst field of the skbuffer in "real time"
> */
> dst_hold(&md->u.dst);
> skb_dst_set(*skb, &md->u.dst);
> /* don't hold the dev we place in skb->dev, the dst is already */
> /* holding it for us */
> (*skb)->dev = md->u.dst.dev;
> MPLS_EXIT;
> return MPLS_RESULT_SUCCESS;
> }
> Old function was:
> MPLS_OUT_OPCODE_PROTOTYPE(mpls_out_op_set)
> {
> struct mpls_dst *md = data;
> MPLS_ENTER;
> /* Release the current dst in the socket buffer */
> if (skb_dst(*skb)) {
> dst_release(skb_dst(*skb));
> }
> /*
> * Update the dst field of the skbuffer in "real time"
> */
> dst_hold(&md->u.dst);
> skb_dst_set(*skb, &md->u.dst);
> /* don't hold the dev we place in skb->dev, the dst is already */
> /* holding it for us */
> (*skb)->dev = md->u.dst.dev;
> MPLS_EXIT;
> return MPLS_RESULT_SUCCESS;
> }
> BR
> Igor Maravić
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-- 
Renato Westphal