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Date: Thu, 7 Dec 2023 11:26:40 -0700
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Subject: Re: [PATCH net-next] ipv6: add debug checks in fib6_info_release()
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From: David Ahern <dsahern@kernel.org>
To: Eric Dumazet <edumazet@google.com>, Kui-Feng Lee <sinquersw@gmail.com>
Cc: patchwork-bot+netdevbpf@kernel.org, Kui-Feng Lee <thinker.li@gmail.com>,
 davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
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On 12/7/23 11:25 AM, David Ahern wrote:
> On 12/7/23 11:22 AM, Eric Dumazet wrote:
>> Feel free to amend the patch, but the issue is that we insert a fib
>> gc_link to a list, then free the fi6 object without removing it first
>> from the external list.
> 
> yes, move the insert down:
> 
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index b132feae3393..7257ba0e72b7 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -3762,12 +3762,6 @@ static struct fib6_info
> *ip6_route_info_create(struct fib6_config *cfg,
>         if (cfg->fc_flags & RTF_ADDRCONF)
>                 rt->dst_nocount = true;
> 
> -       if (cfg->fc_flags & RTF_EXPIRES)
> -               fib6_set_expires_locked(rt, jiffies +
> -
> clock_t_to_jiffies(cfg->fc_expires));
> -       else
> -               fib6_clean_expires_locked(rt);
> -
>         if (cfg->fc_protocol == RTPROT_UNSPEC)
>                 cfg->fc_protocol = RTPROT_BOOT;
>         rt->fib6_protocol = cfg->fc_protocol;
> @@ -3824,6 +3818,12 @@ static struct fib6_info
> *ip6_route_info_create(struct fib6_config *cfg,
>         } else
>                 rt->fib6_prefsrc.plen = 0;
> 
> +
> +       if (cfg->fc_flags & RTF_EXPIRES)
> +               fib6_set_expires_locked(rt, jiffies +
> +
> clock_t_to_jiffies(cfg->fc_expires));
> +       else
> +               fib6_clean_expires_locked(rt);
>         return rt;
>  out:
>         fib6_info_release(rt);


and then failure to insert into the table needs to remove it before the
release too.