From: Hangbin Liu <liuhangbin@gmail.com>
Date: Mon, 27 Jul 2020 19:04:55 +0800
Subject: selftests/bpf: fix netdevsim trap_flow_action_cookie read
Patch-mainline: v5.8
Git-commit: 4bbca662df2523ff7ad3224463f1f28e6a118044
References: bsc#1176774

When read netdevsim trap_flow_action_cookie, we need to init it first,
or we will get "Invalid argument" error.

Fixes: d3cbb907ae57 ("netdevsim: add ACL trap reporting cookie as a metadata")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 tools/testing/selftests/bpf/test_offload.py |    3 +++
 1 file changed, 3 insertions(+)

--- a/tools/testing/selftests/bpf/test_offload.py
+++ b/tools/testing/selftests/bpf/test_offload.py
@@ -318,6 +318,9 @@ class DebugfsDir:
                 continue
 
             if os.path.isfile(p):
+                # We need to init trap_flow_action_cookie before read it
+                if f == "trap_flow_action_cookie":
+                    cmd('echo deadbeef > %s/%s' % (path, f))
                 _, out = cmd('cat %s/%s' % (path, f))
                 dfs[f] = out.strip()
             elif os.path.isdir(p):