[PATCH net 2/2] selftests: tc-testing: add duplicate action delete batch test

[Jamal Hadi Salim <jhs@mojatatu.com>]

tca_action_gd() takes one reference per nested TCA_ACT_TAB entry while
tcf_action_delete() consumes two per slot, so three duplicate
TCA_ACT_INDEX entries in one RTM_DELACTION free the action mid-walk and
the next slot dereferences it.  Assert a duplicate batch is rejected and
the action survives.

Conditions to recreate the bug:
  tc actions add action pass index 1
  tc actions delete action gact index 1 action gact index 1 \
                     action gact index 1

Testing:
  Case 8135 fails on the unfixed kernel (tdc_8135_unfixed.log) and passes
  with the fix, alongside the batch-delete family (tdc_8135_fixed.log).

Tested-by: hybris <hybris@mojatatu.ai>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 .../tc-tests/actions/batch-delete.json        | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/actions/batch-delete.json b/tools/testing/selftests/tc-testing/tc-tests/actions/batch-delete.json
index ef7ca4a6775b..7620e927ae2c 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/actions/batch-delete.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/actions/batch-delete.json
@@ -111,5 +111,38 @@
                 255
             ]
         ]
+    },
+    {
+        "id": "8135",
+        "name": "Reject duplicate action in a delete batch",
+        "category": [
+            "actions",
+            "gact"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$TC actions flush action gact",
+                0,
+                1,
+                255
+            ],
+            "$TC actions add action pass index 1"
+        ],
+        "cmdUnderTest": "$TC actions del action gact index 1 action gact index 1 action gact index 1",
+        "expExitCode": "255",
+        "verifyCmd": "$TC actions ls action gact",
+        "matchPattern": "total acts 1\\b.*index 1 ref 1 bind 0\\b",
+        "matchCount": "1",
+        "teardown": [
+            [
+                "$TC actions flush action gact",
+                0,
+                1,
+                255
+            ]
+        ]
     }
 ]
-- 
2.43.0