Re: Kernel Tainted

> On Oct 5, 2016, at 9:43 PM, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
>
> On 10/05/2016 08:41 PM, reiner peterke wrote:
>> Hi,
>>
>> We are helping a client test an application On Power8 using Postgres
>> 9.5.4 which has been compiled specifically for the Power.
>>
>> This is running on sles12sp1 the current kernel is 3.12.49-11
>>
>> We are getting these kernel warning associated with the postmaster
>> process. The application is handling around 15000TPS It appears that
>> one of these messages is generated for each each transaction which fills
>> up the warn.log quite quickly.
>>
>> I’m trying to understand what is causing the Tainted kernel messages.
>> the warning is at 'WARNING: at ../net/core/dst.c:287’.
>> I’ve found one link that indicates that this is ip6 related.
>> https://brunomgalmeida.wordpress.com/2015/07/23/disable-ipv6-postgres-and-pgbouncer/
>> Is this accurate? And if these action resolve the error, is it more of
>> a bandaid then an actual fix?
>>
>
> As Andres already pointed out, this is most likely a kernel issue, not a PostgreSQL one. The "tainted" has nothing to do with the cause, it's just a way to inform users whether it's a clean kernel build, or if it includes code not available in vanilla kernels etc. The "X" means there are some SuSe-specific modules loaded, IIRC.
>
> And yes, it seems IPv6 related, at least judging by the stack trace:
>
> 0xc0000000016f7d80 (unreliable)
> sk_dst_check+0x174/0x180
> ip6_sk_dst_lookup_flow+0x4c/0x2a0
> udpv6_sendmsg+0x688/0xb20
> inet_sendmsg+0x9c/0x120
> sock_sendmsg+0xec/0x140
> SyS_sendto+0x108/0x150
> SyS_send+0x50/0x70
> SyS_socketcall+0x2a0/0x440
> syscall_exit+0x0/0x7c
>
> You should probably talk to SuSe or whoever supports that system.
>
> regards
>
> --
> Tomas Vondra http://www.2ndQuadrant.com
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>
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Thanks for the clear information.
I think there are a few kernel upgrade we can apply first, then see if that fixes the problem.

Reiner