Fix execution issues for bpf_performance tests on latest kernel #229

Copilot · 2025-11-13T17:40:55Z

Summary

This PR fixes the issue where bpf_performance_runner fails on the latest upstream kernel with error -EINVAL (error code -22, displayed as 4294967274 when printed as unsigned). The error originated from the kernel requiring the BPF_F_TEST_XDP_LIVE_FRAMES flag for XDP programs on newer kernels.

Changes Made:

Added compile-time check for the flags field in bpf_test_run_opts structure (similar to existing HAS_BPF_TEST_RUN_OPTS_BATCH_SIZE)
Set BPF_F_TEST_XDP_LIVE_FRAMES flag when running XDP programs on Linux
Used conditional compilation to ensure backward compatibility with older kernels/libbpf versions
Applied flag using bitwise OR to preserve any existing flags
Updated .gitignore to exclude CodeQL build artifacts
Store program type alongside BPF object to correctly handle reused objects
NEW: Validate program type matches when reusing BPF objects from cache

Testing:

All 42 tests pass successfully with the changes
Verified baseline, helper functions, and various map type tests
No security vulnerabilities detected by CodeQL
Program type is now correctly tracked and validated for both new and reused BPF objects

The fix ensures compatibility with both older and newer kernel versions through conditional compilation, and prevents configuration mismatches when reusing BPF objects.

Original prompt

This section details on the original issue you should resolve

<issue_title>Unable to execute the tests on latest upstream kernel</issue_title>
<issue_description>I'm experiencing issues while testing bpf_performance on the latest upstream kernel. The program fails with the following error:
./bpf_performance_runner -i tests.yml -t "Baseline"
Error: Program returned unexpected result 4294967274 in test Baseline expected 0
The test configuration shows:
=== TEST CONFIGURATION ===
Test name: Baseline
ELF file: baseline.o
Iteration count: 10000000
Batch size: 64
Pass data: 0
Pass context: 1
Expected result: 0
CPU count: 1
The program is returning -EINVAL (error code -22). After some debugging, I found that the error originates from this line: https://elixir.bootlin.com/linux/v6.18-rc5/source/net/bpf/test_run.c#L1231

The issue appears to be that bpf_performance_runner doesn't properly support the BPF_F_TEST_XDP_LIVE_FRAMES flag. I'm curious about which kernel versions are officially supported by this tool.

Since this tool supports both Windows and Linux, I'm uncertain whether BPF_F_TEST_XDP_LIVE_FRAMES and related XDP functionality are implemented on the Windows side to make changes to the tool.

Probably need similar hack like HAS_BPF_TEST_RUN_OPTS_BATCH_SIZE.
Also, I am curious why you chose xdp to run bpf_prog_test_run

Thanks in advance!</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Unable to execute the tests on latest upstream kernel #228

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Alan-Jowett · 2026-01-07T16:54:52Z

@copilot your work on this fix got interrupted. Please resume work.

- Added compile-time check for flags field in bpf_test_run_opts structure - Set BPF_F_TEST_XDP_LIVE_FRAMES flag when running XDP programs on Linux - Fixed issue where programs fail with -EINVAL on latest upstream kernel - Similar approach to existing HAS_BPF_TEST_RUN_OPTS_BATCH_SIZE flag Signed-off-by: GitHub Copilot <copilot@github.com>

Addressed code review feedback to use |= operator instead of direct assignment for better future-proofing. Signed-off-by: GitHub Copilot <copilot@github.com>

Signed-off-by: GitHub Copilot <copilot@github.com>

Copilot · 2026-01-07T17:14:33Z

@copilot your work on this fix got interrupted. Please resume work.

I've resumed and completed the work. The fix has been implemented in commits 169363b and 61ddb2c.

The issue was that the latest upstream kernel requires the BPF_F_TEST_XDP_LIVE_FRAMES flag to be set for XDP programs. I've added:

A compile-time check for the flags field (similar to HAS_BPF_TEST_RUN_OPTS_BATCH_SIZE)
Code to set the BPF_F_TEST_XDP_LIVE_FRAMES flag when running XDP programs on Linux

All 42 tests now pass successfully, and there are no security vulnerabilities.

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Pull request overview

This PR fixes execution issues where the bpf_performance_runner fails on newer Linux kernels that require the BPF_F_TEST_XDP_LIVE_FRAMES flag for XDP programs. The fix uses a compile-time check to detect the availability of the flags field in the bpf_test_run_opts structure, ensuring backward compatibility with older libbpf versions.

Changes:

Added compile-time detection for the flags field in bpf_test_run_opts structure
Updated runner to set BPF_F_TEST_XDP_LIVE_FRAMES flag for XDP programs on Linux
Added CodeQL build artifacts to .gitignore

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
runner/CMakeLists.txt	Added compile-time check for flags field availability in bpf_test_run_opts, following the same pattern as the existing batch_size check
runner/runner.cc	Added linux/bpf.h include, defined BPF_F_TEST_XDP_LIVE_FRAMES constant, tracked program type, and set the flag for XDP programs in both test execution and map state preparation
.gitignore	Added CodeQL build directory artifacts to prevent them from being committed

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runner/runner.cc

Alan-Jowett · 2026-01-21T21:56:40Z

@copilot address and reply to each comment with what you fixed

Fixed issue where actual_prog_type was not updated when reusing BPF objects from the cache. Now storing program type alongside the BPF object in bpf_object_info structure, ensuring correct flag settings for all tests including those with reused objects. Signed-off-by: GitHub Copilot <copilot@github.com>

Copilot · 2026-01-21T22:01:43Z

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

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Pull request overview

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runner/runner.cc

Alan-Jowett · 2026-01-27T16:45:25Z

@copilot address and reply to each comment with what you fixed

Added validation to ensure that when a BPF object is reused from cache, the program_type specified in the YAML matches the type used when the object was first loaded. This prevents silent mismatches where different tests specify different program types for the same ELF file, which would lead to incorrect flag settings and unexpected behavior. Co-authored-by: Alan-Jowett <20480683+Alan-Jowett@users.noreply.github.com>

Copilot · 2026-01-27T16:48:57Z

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

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esm.ubuntu.com
- Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
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Pull request overview

Copilot reviewed 2 out of 3 changed files in this pull request and generated no new comments.

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Copilot AI assigned Copilot and Alan-Jowett Nov 13, 2025

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GitHub Copilot added 3 commits January 7, 2026 17:07

Use bitwise OR for flags field to preserve existing flags

61ddb2c

Addressed code review feedback to use |= operator instead of direct assignment for better future-proofing. Signed-off-by: GitHub Copilot <copilot@github.com>

Update gitignore to exclude CodeQL build artifacts

b9a9a04

Signed-off-by: GitHub Copilot <copilot@github.com>

Copilot AI changed the title ~~[WIP] Fix execution issues for bpf_performance tests on latest kernel~~ Fix execution issues for bpf_performance tests on latest kernel Jan 7, 2026

Copilot finished work on behalf of Alan-Jowett January 7, 2026 17:15

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Fix execution issues for bpf_performance tests on latest kernel #229

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