Hi,
it seems that 6.6rc4 is affected as well:
----
commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f
Author: Budimir Markovic <markovicbudimir@xxxxxxxxx>
Date: Thu Aug 24 01:49:05 2023 -0700
net/sched: sch_hfsc: Ensure inner classes have fsc curve
——
I have not found newer commits that would suggest they change any behaviour around this in any way, but I might be wrong.
Christian
> On 6. Oct 2023, at 11:01, Linux regression tracking (Thorsten Leemhuis) <regressions@xxxxxxxxxxxxx> wrote:
>
> On 06.10.23 10:37, Christian Theune wrote:
>>
>> (prefix, I was not aware of the regression reporting process and incorrectly reported this informally with the developers mentioned in the change)
>
> Don't worry too much about that, but thx for taking care of all the
> details. FWIW, there is one more thing that would be good to know:
>
> Does the problem happen with mainline (e.g. 6.6-rc4) as well? That's
> relevant, as different people might care[1].
>
> Ciao, Thorsten
>
> [1] this among others is explained here:
> https://linux-regtracking.leemhuis.info/post/frequent-reasons-why-linux-kernel-bug-reports-are-ignored/
>
>> I upgraded from 6.1.38 to 6.1.55 this morning and it broke my traffic shaping script, leaving me with a non-functional uplink on a remote router.
>>
>> The script errors out like this:
>>
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + ext=ispA
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + ext_ingress=ifb0
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + modprobe ifb
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + modprobe act_mirred
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc del dev ispA root
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2061]: Error: Cannot delete qdisc with handle of zero.
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + true
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc del dev ispA ingress
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2064]: Error: Cannot find specified qdisc on specified device.
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + true
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc del dev ifb0 root
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2066]: Error: Cannot delete qdisc with handle of zero.
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + true
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc del dev ifb0 ingress
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2067]: Error: Cannot find specified qdisc on specified device.
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + true
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc add dev ispA handle ffff: ingress
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + ifconfig ifb0 up
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc filter add dev ispA parent ffff: protocol all u32 match u32 0 0 action mirred egress redirect dev ifb0
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc qdisc add dev ifb0 root handle 1: hfsc default 1
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc class add dev ifb0 parent 1: classid 1:999 hfsc rt m2 2.5gbit
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2053]: + tc class add dev ifb0 parent 1:999 classid 1:1 hfsc sc rate 50mbit
>> Oct 06 05:49:22 wendy00 isp-setup-shaping-start[2077]: Error: Invalid parent - parent class must have FSC.
>>
>> The error message is also a bit weird (but that’s likely due to iproute2 being weird) as the CLI interface for `tc` and the error message do not map well. (I think I would have to choose `hfsc sc` on the parent to enable the FSC option which isn’t mentioned anywhere in the hfsc manpage).
>>
>> The breaking change was introduced in 6.1.53[1] and a multitude of other currently supported kernels:
>>
>> ----
>> commit a1e820fc7808e42b990d224f40e9b4895503ac40
>> Author: Budimir Markovic <markovicbudimir@xxxxxxxxx>
>> Date: Thu Aug 24 01:49:05 2023 -0700
>>
>> net/sched: sch_hfsc: Ensure inner classes have fsc curve
>>
>> [ Upstream commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f ]
>>
>> HFSC assumes that inner classes have an fsc curve, but it is currently
>> possible for classes without an fsc curve to become parents. This leads
>> to bugs including a use-after-free.
>>
>> Don't allow non-root classes without HFSC_FSC to become parents.
>>
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
>> Reported-by: Budimir Markovic <markovicbudimir@xxxxxxxxx>
>> Signed-off-by: Budimir Markovic <markovicbudimir@xxxxxxxxx>
>> Acked-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
>> Link: https://lore.kernel.org/r/20230824084905.422-1-markovicbudimir@xxxxxxxxx
>> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
>> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>> ----
>>
>> Regards,
>> Christian
>>
>> [1] https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.1.53
>>
>> #regzbot introduced: a1e820fc7808e42b990d224f40e9b4895503ac40
>>
>>
Liebe Grüße,
Christian Theune
--
Christian Theune · ct@xxxxxxxxxxxxxxx · +49 345 219401 0
Flying Circus Internet Operations GmbH · https://flyingcircus.io
Leipziger Str. 70/71 · 06108 Halle (Saale) · Deutschland
HR Stendal HRB 21169 · Geschäftsführer: Christian Theune, Christian Zagrodnick
