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Message-ID: <d973fd6a-4fd0-4578-a784-00ed7fd1c927@gmail.com>
Date: Thu, 7 Dec 2023 11:00:41 -0800
From: Kui-Feng Lee <sinquersw@...il.com>
To: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>
Cc: patchwork-bot+netdevbpf@...nel.org, Kui-Feng Lee <thinker.li@...il.com>,
davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
netdev@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH net-next] ipv6: add debug checks in fib6_info_release()
On 12/7/23 10:40, Kui-Feng Lee wrote:
>
>
> On 12/7/23 10:36, Kui-Feng Lee wrote:
>>
>>
>> On 12/7/23 10:25, 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);
>>> -
>>
>> fib6_set_expires_locked() here actually doesn't insert a fib gc_link
>> since rt->fib6_table is not assigned yet. The gc_link will
>> be inserted by fib6_add() being called later.
>>
>>
>>> 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);
>>
>> However, this should fix the warning messages.
> Just realize this cause inserting the gc_link twice. fib6_add()
> will try to add it again!
I made a minor change to the patch that fix warning messages
provided by David Ahern. Will send an official patch later.
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3762,17 +3762,10 @@ 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;
- rt->fib6_table = table;
rt->fib6_metric = cfg->fc_metric;
rt->fib6_type = cfg->fc_type ? : RTN_UNICAST;
rt->fib6_flags = cfg->fc_flags & ~RTF_GATEWAY;
@@ -3824,6 +3817,17 @@ 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);
+ /* Set fib6_table after fib6_set_expires_locked() to ensure the
+ * gc_link is not inserted until fib6_add() is called to insert the
+ * fib6_info to the fib.
+ */
+ rt->fib6_table = table;
+
return rt;
out:
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