[PATCH v3 net-next 09/10] selftests/tc-testing: test that taprio can only be attached as root

Vladimir Oltean
2023-08-01T18:25:55Z

Check that the "Can only be attached as root qdisc" error message from
taprio is effective by attempting to attach it to a class of another
taprio qdisc. That operation should fail.

In the bug that was squashed by change "net/sched: taprio: try again to
report q->qdiscs[] to qdisc_leaf()", grafting a child taprio to a root
software taprio would be misinterpreted as a change() to the root
taprio. Catch this by looking at whether the base-time of the root
taprio has changed to follow the base-time of the child taprio,
something which should have absolutely never happened assuming correct
semantics.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
---
v2->v3: none
v1->v2: patch is new

.../tc-testing/tc-tests/qdiscs/taprio.json | 48 +++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/taprio.json b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/taprio.json
index 68a7264e083d..8dbed66a9acc 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/taprio.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/taprio.json
@@ -131,5 +131,53 @@
"teardown": [
"echo \"1\" > /sys/bus/netdevsim/del_device"
]
+ },
+ {
+ "id": "39b4",
+ "name": "Reject grafting taprio as child qdisc of software taprio",
+ "category": [
+ "qdisc",
+ "taprio"
+ ],
+ "plugins": {
+ "requires": "nsPlugin"
+ },
+ "setup": [
+ "echo \"1 1 8\" > /sys/bus/netdevsim/new_device",
+ "$TC qdisc replace dev $ETH handle 8001: parent root stab overhead 24 taprio num_tc 8 map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 0 sched-entry S ff 20000000 clockid CLOCK_TAI"
+ ],
+ "cmdUnderTest": "$TC qdisc replace dev $ETH parent 8001:7 taprio num_tc 8 map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 200 sched-entry S ff 20000000 clockid CLOCK_TAI",
+ "expExitCode": "2",
+ "verifyCmd": "$TC -j qdisc show dev $ETH root | jq '.[].options.base_time'",
+ "matchPattern": "0",
+ "matchCount": "1",
+ "teardown": [
+ "$TC qdisc del dev $ETH root",
+ "echo \"1\" > /sys/bus/netdevsim/del_device"
+ ]
+ },
+ {
+ "id": "e8a1",
+ "name": "Reject grafting taprio as child qdisc of offloaded taprio",
+ "category": [
+ "qdisc",
+ "taprio"
+ ],
+ "plugins": {
+ "requires": "nsPlugin"
+ },
+ "setup": [
+ "echo \"1 1 8\" > /sys/bus/netdevsim/new_device",
+ "$TC qdisc replace dev $ETH handle 8001: parent root stab overhead 24 taprio num_tc 8 map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 0 sched-entry S ff 20000000 flags 0x2"
+ ],
+ "cmdUnderTest": "$TC qdisc replace dev $ETH parent 8001:7 taprio num_tc 8 map 0 1 2 3 4 5 6 7 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 base-time 200 sched-entry S ff 20000000 flags 0x2",
+ "expExitCode": "2",
+ "verifyCmd": "$TC -j qdisc show dev $ETH root | jq '.[].options.base_time'",
+ "matchPattern": "0",
+ "matchCount": "1",
+ "teardown": [
+ "$TC qdisc del dev $ETH root",
+ "echo \"1\" > /sys/bus/netdevsim/del_device"
+ ]
}
]
--
2.34.1