Subject: Re: [Patch net v3 2/4] selftests/tc-testing: Add a test case for pfifo_head_drop qdisc when limit==0

From: Jakub Kicinski <[email-masked]>
Date: Tue, 4 Feb 2025 08:46:46 -0800

On Tue, 4 Feb 2025 11:37:03 +0000 Simon Horman wrote:
> On Mon, Feb 03, 2025 at 04:58:39PM -0800, Cong Wang wrote:
> > From: Quang Le <[email-masked]>
> > 
> > When limit == 0, pfifo_tail_enqueue() must drop new packet and
> > increase dropped packets count of the qdisc.
> > 
> > All test results:
> > 
> > 1..16
> > ok 1 a519 - Add bfifo qdisc with system default parameters on egress
> > ok 2 585c - Add pfifo qdisc with system default parameters on egress
> > ok 3 a86e - Add bfifo qdisc with system default parameters on egress with handle of maximum value
> > ok 4 9ac8 - Add bfifo qdisc on egress with queue size of 3000 bytes
> > ok 5 f4e6 - Add pfifo qdisc on egress with queue size of 3000 packets
> > ok 6 b1b1 - Add bfifo qdisc with system default parameters on egress with invalid handle exceeding maximum value
> > ok 7 8d5e - Add bfifo qdisc on egress with unsupported argument
> > ok 8 7787 - Add pfifo qdisc on egress with unsupported argument
> > ok 9 c4b6 - Replace bfifo qdisc on egress with new queue size
> > ok 10 3df6 - Replace pfifo qdisc on egress with new queue size
> > ok 11 7a67 - Add bfifo qdisc on egress with queue size in invalid format
> > ok 12 1298 - Add duplicate bfifo qdisc on egress
> > ok 13 45a0 - Delete nonexistent bfifo qdisc
> > ok 14 972b - Add prio qdisc on egress with invalid format for handles
> > ok 15 4d39 - Delete bfifo qdisc twice
> > ok 16 d774 - Check pfifo_head_drop qdisc enqueue behaviour when limit == 0
> > 
> > Signed-off-by: Quang Le <[email-masked]>
> > Signed-off-by: Cong Wang <[email-masked]>  
> 
> Hi Cong,
> 
> Unfortunately this test still seems to be failing in the CI.
> 
> # not ok 577 d774 - Check pfifo_head_drop qdisc enqueue behaviour when limit == 0
> # Could not match regex pattern. Verify command output:
> # qdisc pfifo_head_drop 1: root refcnt 2 limit 0p
> #  Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
> #  backlog 0b 0p requeues 0
> 
> https://github.com/p4tc-dev/tc-executor/blob/storage/artifacts/977485/1-tdc-sh/stdout

This is starting to feel too much like a setup issue.
Pedro, would you be able to take this series and investigate
why it fails on the TDC runner?