Re: [PATCH] ipv6: fix race condition regarding dst->expires and dst->from.

[YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>]

YOSHIFUJI Hideaki wrote:

> -static inline void rt6_update_expires(struct rt6_info *rt, int timeout)
> +static inline void rt6_update_expires(struct rt6_info *rt0, int timeout)
>  {
> -	if (!(rt->rt6i_flags & RTF_EXPIRES)) {
> -		if (rt->dst.from)
> -			dst_release(rt->dst.from);
> -		/* dst_set_expires relies on expires == 0 
> -		 * if it has not been set previously.
> -		 */
> -		rt->dst.expires = 0;
> -	}
> -
> -	dst_set_expires(&rt->dst, timeout);
> -	rt->rt6i_flags |= RTF_EXPIRES;
> +	struct rt6_info *rt;
> +
> +	for (rt = rt0; rt && !(rt->rt6i_flags & RTF_EXPIRES); rt = rt->dst.from);
> +	if (rt && rt != rt0)
> +		rt0->dst.expires = rt->dst.expires;
> +
> +	dst_set_expires(&rt0->dst, timeout);
> +	rt0->rt6i_flags |= RTF_EXPIRES;
>  }
>  

Oops, I sent wrong version, will resend.

--yoshfuji