contest: env_check: fix thee netdev NL state saving

Commit 1bd4244 ("contest: env_check: save netdev NL state")
a bunch of netdev state to the checking but ynl wasn't available
on the system that run HW tests at the time. So this was entirely
dead code. Now that ynl is installed these are causing false
positives.

Filter out various unstable IDs and stats. Try to give page pools
some time to get released.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

contest/scripts/env_check.py

@@ -8,6 +8,7 @@
 import os
 import subprocess
 import sys
+import time
 
 
 def run_cmd_text(cmd):
@@ -33,8 +34,24 @@ def run_cmd_json(cmd):
     return ret
 
 
+def wait_for_detached_pp():
+    """Wait for detached (zombie) page pools to disappear, up to 60s."""
+    deadline = time.time() + 60
+    while time.time() < deadline:
+        pp_all = run_cmd_json("ynl --family netdev --output-json --dump page-pool-get")
+        if not isinstance(pp_all, list):
+            break
+        detached = [pp for pp in pp_all if "detach-time" in pp]
+        if not detached:
+            break
+        time.sleep(1)
+
+
 def collect_system_state():
     """Collect network interface information."""
+
+    wait_for_detached_pp()
+
     state = {
         "links": {},
         "chans": {},
@@ -70,7 +87,19 @@ def collect_system_state():
 
             cmd = f'ynl --family netdev --output-json {method} {op} '
             cmd += "--json '{" + f'"ifindex": {ifindex}' + "}'"
-            state["netdev-" + op][ifname] = run_cmd_json(cmd)
+            data = run_cmd_json(cmd)
+
+            # Strip attributes that change across runs
+            drop_keys = {'id', 'napi-id', 'irq', 'inflight', 'inflight-mem'}
+            if isinstance(data, list):
+                for obj in data:
+                    for key in drop_keys:
+                        obj.pop(key, None)
+            elif isinstance(data, dict):
+                for key in drop_keys:
+                    data.pop(key, None)
+
+            state["netdev-" + op][ifname] = data
 
     return state