Re: [PATCH v2] ipv6: default IPV6_SIT to m

Alyssa Ross
2026-05-04T14:30:59Z

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Fernando Fernandez Mancera <fmancera@suse.de> writes:

> On 5/3/26 9:25 PM, Alyssa Ross wrote:
>> This basically defaulted to m until recently, since IPV6 defaulted to
>> m. Since IPV6 was changed to a boolean with a default of y, IPV6_SIT
>> started defaulting to built-in as well. This results in a surprise
>> sit0 device by default for defconfig (and defconfig-derived config)
>> users at boot. For me, this broke an (admittedly non-robust) script.
>> Preserve the behaviour of most configs by avoiding building this
>> module, that's probably overall seldom used compared to IPv6 as a
>> whole, into the kernel.
>>
>> Fixes: 309b905deee59 ("ipv6: convert CONFIG_IPV6 to built-in only and clean up Kconfigs")
>> Signed-off-by: Alyssa Ross <hi@alyssa.is>
>
> Hi, I am not sure about this. IPV6_SIT was already defaulting to 'y' for
> most distributions (except for ARM). Sure, if you had CONFIG_IPV6=m then
> CONFIG_IPV6_SIT was defaulting to 'm'.
>
> Hm. Maybe we can aim this for net-next tree instead of net? I just don't
> think this is a fix but a change in behavior. FWIW, it makes sense to me
> to have this as a module by default.
>
> Let's see what do others think.

Yes, it appears you're right. I had only tested on ARM. In that case,
perhaps it make sense to instead set this to m in the arm64 defconfig, to
preserve the previous situation, but I can also see the value in
reducing platform discongruity by letting it change to y on arm64 too.

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