Subject: Re: Linux 4.2.4

From: Gerhard Wiesinger <[email-masked]>
Date: Sun, 25 Oct 2015 21:08:57 +0100

On 25.10.2015 20:46, Jozsef Kadlecsik wrote:
> Hi,
>
> On Sun, 25 Oct 2015, Gerhard Wiesinger wrote:
>
>> On 25.10.2015 10:46, Willy Tarreau wrote:
>>> ipset *triggered* the problem. The whole stack dump would tell more.
>> OK, find the stack traces in the bug report:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1272645
>>
>> Kernel 4.1.10 triggered also a kernel dump when playing with ipset commands
>> and IPv6, details in the bug report  ....
> It seems to me it is an architecture-specific alignment issue. I don't
> have a Cortex-A7 ARM hardware and qemu doesn't seem to support it either,
> so I'm unable to reproduce it (ipset passes all my tests on my hardware,
> including more complex ones than what breaks here). My first wild guess is
> that the dynamic array of the element structure is not aligned properly.
> Could you give a try to the next patch?
>
> diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
> index afe905c..1cf357d 100644
> --- a/net/netfilter/ipset/ip_set_hash_gen.h
> +++ b/net/netfilter/ipset/ip_set_hash_gen.h
> @@ -1211,6 +1211,9 @@ static const struct ip_set_type_variant mtype_variant = {
>   	.same_set = mtype_same_set,
>   };
>   
> +#define IP_SET_BASE_ALIGN(dtype)	\
> +	ALIGN(sizeof(struct dtype), __alignof__(struct dtype))
> +
>   #ifdef IP_SET_EMIT_CREATE
>   static int
>   IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
> @@ -1319,12 +1322,12 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
>   #endif
>   		set->variant = &IPSET_TOKEN(HTYPE, 4_variant);
>   		set->dsize = ip_set_elem_len(set, tb,
> -				sizeof(struct IPSET_TOKEN(HTYPE, 4_elem)));
> +				IP_SET_BASE_ALIGN(IPSET_TOKEN(HTYPE, 4_elem)));
>   #ifndef IP_SET_PROTO_UNDEF
>   	} else {
>   		set->variant = &IPSET_TOKEN(HTYPE, 6_variant);
>   		set->dsize = ip_set_elem_len(set, tb,
> -				sizeof(struct IPSET_TOKEN(HTYPE, 6_elem)));
> +				IP_SET_BASE_ALIGN(IPSET_TOKEN(HTYPE, 6_elem)));
>   	}
>   #endif
>   	if (tb[IPSET_ATTR_TIMEOUT]) {
>
> If that does not solve it, then could you help to narrow down the issue?
> Does the bug still appear if your remove the counter extension of the set?
>

Hello Jozsef,

Patch applied well, compiling ...

Interesting, that it didn't happen before. Device is in production for 
more than 2 month without any issue.

Also any idea regarding the second isssue? Or do you think it has the 
same root cause?

Greetings from Vienna, Austria :-)

BTW: You can get the Banana Pi R1 for example at:
http://www.aliexpress.com/item/BPI-R1-Set-1-R1-Board-Clear-Case-5dB-Antenna-Power-Adapter-Banana-PI-R1-Smart/32362127917.html
I can really recommend it as a router. Power consumption is as less as 
3W. Price is also IMHO very good.

Ciao,
Gerhard