On Mon, 02 Nov 2020 13:37:00 +0100, Toke wrote:
Dean Scarff <[email protected]> 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.
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