Re: [BUG] ipv6, rawv6_close(): BUG: unable to handle kernel pagingrequest

From: Srivatsa S. Bhat
Date: Mon Jul 22 2013 - 11:29:12 EST


On 07/22/2013 05:49 PM, Hannes Frederic Sowa wrote:
> On Mon, Jul 22, 2013 at 06:29:58PM +0800, Fan Du wrote:
>> Hallo Srivatsa
>>
>>
>> On 2013å07æ22æ 02:28, Srivatsa S. Bhat wrote:
>>> Hi,
>>>
>>> I'm seeing this on every boot.
>>>
>>> Version: Latest mainline (commit ea45ea70b)
>>
>> I tested with this commit using your updated IPv6 config, this incident
>> didn't show up after several times of reboot.
>> Could you please elaborate your testing details if possible?
>>
>> A wild guess, it dereference mrt->mroute6_sk, indicating mrt is invalid.
>
> Yes, that seems to be the case.
>
> Could you test the following patch if you have a bit of time?
>
> rtnl_lock is for some functions down lower the call stack in ip6mr_free_table.
>

This patch fixed the issue I was facing. Thanks!

Tested-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

Regards,
Srivatsa S. Bhat

> diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
> index 583e8d4..03986d3 100644
> --- a/net/ipv6/ip6mr.c
> +++ b/net/ipv6/ip6mr.c
> @@ -259,10 +259,12 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
> {
> struct mr6_table *mrt, *next;
>
> + rtnl_lock();
> list_for_each_entry_safe(mrt, next, &net->ipv6.mr6_tables, list) {
> list_del(&mrt->list);
> ip6mr_free_table(mrt);
> }
> + rtnl_unlock();
> fib_rules_unregister(net->ipv6.mr6_rules_ops);
> }
> #else
> @@ -289,7 +291,10 @@ static int __net_init ip6mr_rules_init(struct net *net)
>
> static void __net_exit ip6mr_rules_exit(struct net *net)
> {
> + rtnl_lock();
> ip6mr_free_table(net->ipv6.mrt6);
> + net->ipv6.mrt6 = NULL;
> + rtnl_unlock();
> }
> #endif
>
>

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