linux-stable.git/tools/testing/selftests/tc-testing, branch v6.15

selftests/tc-testing: Add an HFSC qlen accounting test

2025-05-22T09:16:51+00:00

This test reproduces a scenario where HFSC queue length and backlog accounting
can become inconsistent when a peek operation triggers a dequeue and possible
drop before the parent qdisc updates its counters. The test sets up a DRR root
qdisc with an HFSC class, netem, and blackhole children, and uses Scapy to
inject a packet. It helps to verify that HFSC correctly tracks qlen and backlog
even when packets are dropped during peek-induced dequeue.

Cc: Mingi Cho 
Signed-off-by: Cong Wang 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250518222038.58538-3-xiyou.wangcong@gmail.com
Reviewed-by: Jamal Hadi Salim 
Signed-off-by: Paolo Abeni

selftests/tc-testing: Add qdisc limit trimming tests

2025-05-09T11:34:38+00:00

Added new test cases for FQ, FQ_CODEL, FQ_PIE, and HHF qdiscs to verify queue
trimming behavior when the qdisc limit is dynamically reduced.

Each test injects packets, reduces the qdisc limit, and checks that the new
limit is enforced. This is still best effort since timing qdisc backlog
is not easy.

Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

selftests/tc-testing: Add a test case to cover basic HTB+FQ_CODEL case

2025-05-05T20:51:33+00:00

Integrate the reproducer from Alan into TC selftests and use scapy to
generate TCP traffic instead of relying on ping command.

Cc: Alan J. Wylie 
Signed-off-by: Cong Wang 
Link: https://patch.msgid.link/20250428232955.1740419-3-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski

selftests: tc-testing: Add TDC tests that exercise reentrant enqueue behaviour

2025-04-28T22:55:07+00:00

Add 5 TDC tests that exercise the reentrant enqueue behaviour in drr,
ets, qfq, and hfsc:

- Test DRR's enqueue reentrant behaviour with netem (which caused a
  double list add)
- Test ETS's enqueue reentrant behaviour with netem (which caused a double
  list add)
- Test QFQ's enqueue reentrant behaviour with netem (which caused a double
  list add)
- Test HFSC's enqueue reentrant behaviour with netem (which caused a UAF)
- Test nested DRR's enqueue reentrant behaviour with netem (which caused a
  double list add)

Acked-by: Jamal Hadi Salim 
Signed-off-by: Victor Nogueira 
Link: https://patch.msgid.link/20250425220710.3964791-6-victor@mojatatu.com
Signed-off-by: Jakub Kicinski

selftests/tc-testing: Add test for HFSC queue emptying during peek operation

2025-04-24T00:16:50+00:00

Add a selftest to exercise the condition where qdisc implementations
like netem or codel might empty the queue during a peek operation.
This tests the defensive code path in HFSC that checks the queue length
again after peeking to handle this case.

Based on the reproducer from Gerrard, improved by Jamal.

Reported-by: Gerrard Tai 
Signed-off-by: Cong Wang 
Tested-by: Victor Nogueira 
Reviewed-by: Jamal Hadi Salim 
Link: https://patch.msgid.link/20250417184732.943057-4-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski

selftests/tc-testing: Add test for echo of big TC filters

2025-04-11T23:33:32+00:00

Add a selftest that checks whether the kernel can successfully echo a
big tc filter, to test the fix introduced in commit:

369609fc6272 ("tc: Ensure we have enough buffer space when sending filter netlink notifications")

Signed-off-by: Toke Høiland-Jørgensen 
Tested-by: Victor Nogueira 
Link: https://patch.msgid.link/20250410104322.214620-1-toke@redhat.com
Signed-off-by: Jakub Kicinski

selftests/tc-testing: sfq: check that a derived limit of 1 is rejected

2025-04-09T11:55:48+00:00

Because the limit is updated indirectly when other parameters are
updated, there are cases where even though the user requests a limit
of 2 it can actually be set to 1.

Add the following test cases to check that the kernel rejects them:
- limit 2 depth 1 flows 1
- limit 2 depth 1 divisor 1

Signed-off-by: Octavian Purdila 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

selftests/tc-testing: Add a test case for FQ_CODEL with ETS parent

2025-04-08T08:58:16+00:00

Add a test case for FQ_CODEL with ETS parent to verify packet drop
behavior when the queue becomes empty. This helps ensure proper
notification mechanisms between qdiscs.

Note this is best-effort, it is hard to play with those parameters
perfectly to always trigger ->qlen_notify().

Cc: Pedro Tammela 
Signed-off-by: Cong Wang 
Reviewed-by: Victor Nogueira 
Link: https://patch.msgid.link/20250403211636.166257-6-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim 
Signed-off-by: Paolo Abeni

selftests/tc-testing: Add a test case for FQ_CODEL with DRR parent

2025-04-08T08:58:16+00:00

Add a test case for FQ_CODEL with DRR parent to verify packet drop
behavior when the queue becomes empty. This helps ensure proper
notification mechanisms between qdiscs.

Note this is best-effort, it is hard to play with those parameters
perfectly to always trigger ->qlen_notify().

Cc: Pedro Tammela 
Signed-off-by: Cong Wang 
Reviewed-by: Victor Nogueira 
Link: https://patch.msgid.link/20250403211636.166257-5-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim 
Signed-off-by: Paolo Abeni

selftests/tc-testing: Add a test case for FQ_CODEL with HFSC parent

2025-04-08T08:58:15+00:00

Add a test case for FQ_CODEL with HFSC parent to verify packet drop
behavior when the queue becomes empty. This helps ensure proper
notification mechanisms between qdiscs.

Note this is best-effort, it is hard to play with those parameters
perfectly to always trigger ->qlen_notify().

Cc: Pedro Tammela 
Signed-off-by: Cong Wang 
Reviewed-by: Victor Nogueira 
Link: https://patch.msgid.link/20250403211636.166257-4-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim 
Signed-off-by: Paolo Abeni