Subject: Re: nf_nat_pptp 4.12.3 kernel lockup/reboot

From: Denys Fedoryshchenko <[email-masked]>
Date: Tue, 25 Jul 2017 10:27:01 +0300

On 2017-07-24 19:20, Florian Westphal wrote:
> Florian Westphal <[email-masked]> wrote:
>> Denys Fedoryshchenko <[email-masked]> wrote:
>> > Hi,
>> >
>> > I am trying to upgrade kernel 4.11.8 to 4.12.3 (it is a nat/router, handling
>> > approx 2gbps of pppoe users traffic) and noticed that after while server
>> > rebooting(i have set reboot on panic and etc).
>> > I can't run serial console, and in pstore / netconsole there is nothing.
>> > Best i got is some very short message about softlockup in ipmi, but as
>> > storage very limited there - it is near useless.
>> >
>> > By preliminary testing (can't do it much, as it's production) - it seems
>> > following lines causing issue, they worked in 4.11.8 and no more in 4.12.3.
>> 
>> Wild guess here, does this help?
>> 
>> diff --git a/net/netfilter/nf_conntrack_helper.c 
>> b/net/netfilter/nf_conntrack_helper.c
>> --- a/net/netfilter/nf_conntrack_helper.c
>> +++ b/net/netfilter/nf_conntrack_helper.c
>> @@ -266,6 +266,8 @@ int __nf_ct_try_assign_helper(struct nf_conn *ct, 
>> struct nf_conn *tmpl,
>>                 help = nf_ct_helper_ext_add(ct, helper, flags);
>>                 if (help == NULL)
>>                         return -ENOMEM;
>> +              	if (!nf_ct_ext_add(ct, NF_CT_EXT_NAT, flags));
> 
> sigh, stupid typo, should be no ';' at the end above.

Tested, it looks like not hanging anymore (before it was hanging within 
10 minutes)
Probably i will wait 24h testing cycle.