[PATCH net-next] selftests: net: bpf_offload: print loaded programs on mismatch

[Hangbin Liu <liuhangbin@gmail.com>]

The test sometimes fails due to an unexpected number of loaded programs. e.g

  FAIL: 2 BPF programs loaded, expected 1
    File "/usr/libexec/kselftests/net/./bpf_offload.py", line 940, in <module>
      progs = bpftool_prog_list(expected=1)
    File "/usr/libexec/kselftests/net/./bpf_offload.py", line 187, in bpftool_prog_list
      fail(True, "%d BPF programs loaded, expected %d" %
    File "/usr/libexec/kselftests/net/./bpf_offload.py", line 89, in fail
      tb = "".join(traceback.extract_stack().format())

However, the logs do not show which programs were actually loaded, making it
difficult to debug the failure.

Add printing of the loaded programs when a mismatch is detected to help
troubleshoot such errors. The list is printed on a new line to avoid breaking
the current log format.

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 tools/testing/selftests/net/bpf_offload.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/bpf_offload.py b/tools/testing/selftests/net/bpf_offload.py
index b2c271b79240..c856d266c8f3 100755
--- a/tools/testing/selftests/net/bpf_offload.py
+++ b/tools/testing/selftests/net/bpf_offload.py
@@ -184,8 +184,8 @@ def bpftool_prog_list(expected=None, ns="", exclude_orphaned=True):
         progs = [ p for p in progs if not p['orphaned'] ]
     if expected is not None:
         if len(progs) != expected:
-            fail(True, "%d BPF programs loaded, expected %d" %
-                 (len(progs), expected))
+            fail(True, "%d BPF programs loaded, expected %d\nLoaded Progs:\n%s" %
+                 (len(progs), expected, pp.pformat(progs)))
     return progs
 
 def bpftool_map_list(expected=None, ns=""):
-- 
2.50.1