Re: [netdev] htb_qlen_notify warning triggered after qdisc_tree_reduce_backlog change

Jakub Kicinski:

Is the issue easily reproducible ?

   Yes, 100% reproducible when with the kernel commit of .
   it caused by the kernel commit of e269f29e9395527bc00c213c6b15da04ebb35070
   when I revert this commit, it is ok.

Could you try your reproducer on the latest upstream kernel ?

    for 5.15 kernel , 5.15.189 is the latest upstream, this commit is introduced in 5.15.187.


I don't know if OVS should be updated according to the updating of commit e269f29e9395527bc00c213c6b15da04ebb35070
or the commit of kernel have some issue itself ?


________________________________________
From: Jakub Kicinski <kuba@kernel.org>
Sent: Saturday, August 9, 2025 4:29 AM
To: He, Guocai (CN)
Cc: Lion Ackermann; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; ovs-discuss@openvswitch.org
Subject: Re: [netdev] htb_qlen_notify warning triggered after qdisc_tree_reduce_backlog change

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On Wed, 6 Aug 2025 08:29:34 +0000 He, Guocai (CN) wrote:

### Environment
- Kernel version: 5.15.189-rt76-yocto-preempt-rt
- Open vSwitch version: 2.17.9

### Issue
After applying the QoS configuration, the following warning appears in dmesg:
[73591.168117] WARNING: CPU: 6 PID: 61296 at net/sched/sch_htb.c:609 htb_qlen_notify+0x3a/0x40 [sch_htb]

Is the issue easily reproducible ?
Could you try your reproducer on the latest upstream kernel ?