For those not follow following sch_cake on github or the latest kernels
changes;
due to recent updates to net_sched backported from 4.6 to kernels 4.4.11 and
4.5.5, the current sch_cake code on github needs an update and I believe is
unsuitable for use at this time (though I am in no way an authoritative
source
on this matter). Since OpenWRT/LEDE is planning 4.4.x for the next release I
thought it relevant to post this since I've had quite a few headaches
troubleshooting kernel BUG checks and stack traces which are presumably
related.

There's a simple bandaid fix in issue #20 in sch_cake.c
which changes the following:

#if KERNEL_VERSION(4, 6, 0) > LINUX_VERSION_CODE
to:
#if KERNEL_VERSION(4, 4, 0) > LINUX_VERSION_CODE

Although now it should probably be (4, 4, 11) and above, but I believe these
issues stem a bit deeper than this can fix since I've seen stack traces with
layer_cake.qos with kernel 4.4.10 (with original code) and on kernel 4.4.11
with the bandaid fix.

I must also point out that my own issues could be a platform-specific for
x86/Debian, though chromi@github had commented previously that the current
code
is unstable with diffserv turned on so I am unsure if this is related but I
have not been able to reproduce the stack traces after removing sch_cake.

Relevant links:
https://github.com/dtaht/sch_cake/issues/20
https://git.kernel.org/cgit/linux/kernel/git/stable/stable-queue.git/tree/releases/4.4.11
https://git.kernel.org/cgit/linux/kernel/git/stable/stable-queue.git/tree/releases/4.5.5