From: Dean Scarff <dos@scarff.id.au>
To: <cake@lists.bufferbloat.net>
Subject: Re: [Cake] NLA_F_NESTED is missing
Date: Tue, 03 Nov 2020 12:11:06 +1100 [thread overview]
Message-ID: <e68ac9a6a490fcefb10383342d9c981a@scarff.id.au> (raw)
In-Reply-To: <87d00wkk9f.fsf@toke.dk>
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.
My current theory (despite the 4 combinations I tried) is that there's
some mismatch between Raspbian/Debian's tc and the kernel (somewhere in
the tc's qdisc code it's calling nla_parse_nested but not setting
nla_type), but it's odd that nobody else can repro. tbh the Debian
patches look pretty innocent too:
https://salsa.debian.org/debian/iproute2/-/tree/558bae88bd0befc1bf3e1070733bafd522e44992/debian/patches
I should be able to figure it out by poking around in tc with gdb.
next prev parent reply other threads:[~2020-11-03 1:11 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 [this message]
2020-11-03 8:07 ` Dean Scarff
2020-11-03 11:00 ` Toke Høiland-Jørgensen
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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