Tests: Load without -d in the verifier tests, and report a timeout properly

-d asks the kernel for the instruction-level verifier log on every load. For
loop1, which makes the verifier walk nested loops, that log outgrows libbpf's
buffer; the kernel fails the load with ENOSPC, libbpf doubles the buffer and
verifies again, and on CI the load ran past the 30s timeout. A rejection
still comes with its log without -d, since libbpf retries a failed load at
log level 1 and prints it as a warning.

The timeout path also returned a bare string where callers expect stdout and
stderr, so a timeout surfaced as an AttributeError instead of the timeout.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: r41k0u

tests/framework/verifier.py

@@ -3,25 +3,34 @@
 from collections import namedtuple
 from pathlib import Path
 
+Output = namedtuple("Output", ["stdout", "stderr"])
 
-def verify_object(obj_path: Path) -> tuple[bool, str]:
-    """Run bpftool prog load -d to verify a BPF object file against the kernel verifier.
+
+def verify_object(obj_path: Path) -> tuple[bool, Output]:
+    """Run bpftool prog load to verify a BPF object file against the kernel verifier.
 
     Pins the program temporarily at /sys/fs/bpf/bpf_prog_test_<uuid>, then removes it.
-    Returns (success, combined_output). Requires sudo / root.
+    Returns (success, Output(stdout, stderr)). Requires sudo / root.
+
+    No -d: it asks the kernel for the full instruction-level log (log level
+    1+2+4) on every load. For a program that makes the verifier walk a loop that
+    log outgrows libbpf's buffer, the kernel then fails the load with ENOSPC, and
+    libbpf doubles the buffer and verifies the whole program again, until the
+    load takes longer than the timeout. A rejection still comes with its log:
+    libbpf retries a failed load at log level 1 and prints the log as a warning.
     """
     pin_path = f"/sys/fs/bpf/bpf_prog_test_{uuid.uuid4().hex[:8]}"
     try:
         result = subprocess.run(
-            ["sudo", "bpftool", "prog", "load", "-d", str(obj_path), pin_path],
+            ["sudo", "bpftool", "prog", "load", str(obj_path), pin_path],
             capture_output=True,
             text=True,
             timeout=30,
         )
-        Output = namedtuple("Output", ["stdout", "stderr"])
-        output = Output(stdout=result.stdout, stderr=result.stderr)
-        return result.returncode == 0, output
+        return result.returncode == 0, Output(
+            stdout=result.stdout, stderr=result.stderr
+        )
     except subprocess.TimeoutExpired:
-        return False, "bpftool timed out after 30s"
+        return False, Output(stdout="", stderr="bpftool timed out after 30s")
     finally:
         subprocess.run(["sudo", "rm", "-f", pin_path], check=False, capture_output=True)

tests/test_verifier.py

@@ -2,7 +2,7 @@
 Level 3 — Kernel verifier tests.
 
 For every passing BPF test file, compiles to a .o and runs:
-    sudo bpftool prog load -d <file.o> /sys/fs/bpf/bpf_prog_test_<id>
+    sudo bpftool prog load <file.o> /sys/fs/bpf/bpf_prog_test_<id>
 
 These tests are opt-in: they require sudo and kernel access, and are gated
 behind the `verifier` pytest mark. Run with: