From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Dean Scarff <dos@scarff.id.au>, cake@lists.bufferbloat.net
Subject: Re: [Cake] NLA_F_NESTED is missing
Date: Tue, 03 Nov 2020 12:00:55 +0100 [thread overview]
Message-ID: <87k0v2k8m0.fsf@toke.dk> (raw)
In-Reply-To: <e68ac9a6a490fcefb10383342d9c981a@scarff.id.au>
Dean Scarff <dos@scarff.id.au> writes:
> On Mon, 02 Nov 2020 13:37:00 +0100, Toke wrote:
>> Dean Scarff <dos@scarff.id.au> writes:
>>
>>> Hi,
>>>
>>> I've been happily running the out-of-tree sch_cake on my Raspberry
>>> Pi
>>> since 2015. However, I recently upgraded my kernel (to 5.4.72 from
>>> Raspbian's raspberrypi-kernel 1.20201022-1), which comes with the
>>> sch_cake in mainline. Now, when running:
>>>
>>> sudo /sbin/tc qdisc add dev ppp0 root cake
>>>
>>> I get the error:
>>>
>>> Error: NLA_F_NESTED is missing.
>>>
>>> I get this error with the sch_cake in mainline, and also with
>>> sch_cake
>>> built out-of-tree. I also get the error with both Debian's
>>> iproute2
>>> 5.9.0-1 (built myself via debian/rules) and "tc" from dtaht's
>>> tc-adv
>>> repo.
>>>
>>> Any ideas on what this error means and how to fix it?
>>
>> I just tried building a 5.4.72 kernel and couldn't reproduce this, so
>> it
>> seems it's a fault with the raspberry pi kernel; I guess opening a
>> bug
>> against that would be the way to go?
>>
>> As for what's actually causing this, I couldn't find anything obvious
>> that touches this code in the qdisc layer; but I suppose it has
>> something to do with the core qdisc netlink parsing code?
>>
>> -Toke
>
> Thanks for the data point.
>
> For the record, the relevant kernel source is:
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/net/netlink.h?h=v5.4.72#n1143
> and the Pi branch:
> https://github.com/raspberrypi/linux/blob/raspberrypi-kernel_1.20201022-1/include/net/netlink.h#L1143
>
> It seems very unlikely that the Pi folks are patching the netlink
> stuff, so I don't think I'll get much traction there unless I can call
> out something specifically wrong with their patchset.
Well, something odd is certainly going on. The error message you're
quoting comes form a part of the netlink parsing code (in the kernel)
that shouldn't even be hit by the qdisc addition: NLA_F_NESTED parsing
is only enabled in 'strict' validation mode, which is not used for
qdiscs.
So IDK, maybe a compiler issue or a bit that gets set wrong somewhere?
Bisecting the kernel may be the only option here, I don't think you're
going to find anything in userspace...
-Toke
next prev parent reply other threads:[~2020-11-03 11:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-01 10:15 Dean Scarff
2020-11-01 16:53 ` Y
2020-11-02 12:37 ` Toke Høiland-Jørgensen
2020-11-03 1:11 ` Dean Scarff
2020-11-03 8:07 ` Dean Scarff
2020-11-03 11:00 ` Toke Høiland-Jørgensen [this message]
2020-11-04 5:48 ` Dean Scarff
2020-11-04 11:27 ` Toke Høiland-Jørgensen
2020-11-03 1:14 ` Jonathan Morton
2020-11-03 1:51 ` Dean Scarff
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