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Message-ID: <55cfe0a4-3874-5683-320e-0dec70bd2034@mojatatu.com>
Date:   Wed, 14 Jun 2023 13:44:09 -0300
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Subject: Re: [PATCH v2 net-next 8/9] selftests/tc-testing: test that taprio
 can only be attached as root
To:     Vladimir Oltean <vladimir.oltean@nxp.com>, netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
        Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>,
        Peilin Ye <yepeilin.cs@gmail.com>,
        Richard Cochran <richardcochran@gmail.com>,
        Zhengchao Shao <shaozhengchao@huawei.com>,
        Maxim Georgiev <glipus@gmail.com>
References: <20230613215440.2465708-1-vladimir.oltean@nxp.com>
 <20230613215440.2465708-9-vladimir.oltean@nxp.com>
Content-Language: en-US
From:   Pedro Tammela <pctammela@mojatatu.com>
In-Reply-To: <20230613215440.2465708-9-vladimir.oltean@nxp.com>
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On 13/06/2023 18:54, Vladimir Oltean wrote:
> 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>

> ---
> 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 a44455372646..58d4d97f4499 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"
> +        ]
>       }
>   ]