[bpf-ci-bot] Colons in traffic monitor pcap filenames break artifact upload in CI

[kernel-patches-review-bot]

Summary

The net_timestamping BPF selftest has subtests with colons in their names (INET4: bpf timestamping, etc.). When the traffic monitor is enabled in CI, these colons end up in pcap log filenames, which GitHub Actions' upload-artifact@v4 rejects. This causes every test_progs_parallel and test_progs_no_alu32_parallel job to fail at the artifact upload step, even when all tests pass.

Failure Details

• Test / Component: Traffic monitor pcap filename generation (encode_test_name() in network_helpers.c) triggered by net_timestamping subtests
• Frequency: Every run — affects all test_progs_parallel and test_progs_no_alu32_parallel jobs on x86_64 gcc-15 since the net_timestamping test was merged
• Failure mode: Artifact upload timeout/rejection — the test itself passes, but CI job is marked as failed
• Affected architectures: x86_64 (parallel jobs only run on x86_64)
• CI runs observed:
  • https://github.com/kernel-patches/bpf/actions/runs/22571439374 (test_progs_parallel, Mar 2)
  • https://github.com/kernel-patches/bpf/actions/runs/22548287519 (test_progs_no_alu32_parallel, Mar 1)
  • https://github.com/kernel-patches/bpf/actions/runs/22548322990 (test_progs_parallel, Mar 1)
  • https://github.com/kernel-patches/bpf/actions/runs/22548372137 (test_progs_no_alu32_parallel, Mar 1)
  • https://github.com/kernel-patches/bpf/actions/runs/22571297154 (test_progs_no_alu32_parallel, Mar 2)
  • https://github.com/kernel-patches/bpf/actions/runs/22571185934 (test_progs_parallel, Mar 2)

Root Cause Analysis

The encode_test_name() function at tools/testing/selftests/bpf/network_helpers.c:1137 constructs filenames for traffic monitor pcap logs. It sanitizes / and (space) characters by replacing them with underscores, but does not sanitize colons (:).

The net_timestamping test (tools/testing/selftests/bpf/prog_tests/net_timestamping.c:231-238), introduced in commit f4924aec58dd ("selftests/bpf: Add simple bpf tests in the tx path for timestamping feature"), has four subtests with colons in their names:

test__start_subtest("INET4: bpf timestamping")
test__start_subtest("INET4: bpf and socket timestamping")
test__start_subtest("INET6: bpf timestamping")
test__start_subtest("INET6: bpf and socket timestamping")

When traffic monitoring is enabled in CI (TEST_PROGS_TRAFFIC_MONITOR=true in the CI environment, which passes -m '*' to test_progs), traffic_monitor_start() calls encode_test_name() which produces filenames like:

packets-133-0-net_timestamping__INET4:_bpf_timestamping-net_timestamping_ns.log

The colon in INET4: passes through encode_test_name() unsanitized. GitHub Actions' upload-artifact@v4 rejects files with colons (and other special characters: ", <, >, |, *, ?), producing this error:

The path for one of the files in artifact is not valid:
/packets-133-0-net_timestamping__INET4:_bpf_timestamping-net_timestamping_ns.log.
Contains the following character: Colon :

The upload then times out, and the entire job is marked as failed.

Proposed Fix

Replace the two separate strchr() loops in encode_test_name() with a single strpbrk() call that sanitizes all problematic characters (/, , :, ") at once. This is both a fix and a simplification.

See patch: 0001-selftests-bpf-Sanitize-colons-in-traffic-monitor-pca.patch

-	while ((p = strchr(buf, '/')))
-		*p = '_';
-	while ((p = strchr(buf, ' ')))
+	while ((p = strpbrk(buf, " /:\"")))
 		*p = '_';

Impact

Without the fix, every CI run's parallel test jobs (test_progs_parallel and test_progs_no_alu32_parallel) fail at the artifact upload step. While these parallel jobs use continue_on_error: true so they don't block the overall CI run, they still produce a "failure" status that:

• Degrades CI signal quality (2 false failures per run)
• Makes it harder to notice genuine regressions in parallel test results
• Wastes developer time investigating false failures

References

• tools/testing/selftests/bpf/network_helpers.c:1137 — encode_test_name() function
• tools/testing/selftests/bpf/prog_tests/net_timestamping.c:231 — subtests with colons
• Commit f4924aec58dd — introduced net_timestamping test with colon-containing subtest names
• Commit f52403b6bfea — introduced encode_test_name() and traffic monitor filename generation
• GitHub Actions artifact upload character restrictions: ", :, <, >, |, *, ?

[kernel-patches-review-bot]

0001-selftests-bpf-Sanitize-colons-in-traffic-monitor-pca.patch

From 60308d69feae0efda84b22834cf71415d8bd6e99 Mon Sep 17 00:00:00 2001
From: "claude[bot]" <41898282+claude[bot]@users.noreply.github.com>
Date: Mon, 2 Mar 2026 12:52:10 +0000
Subject: [PATCH] selftests/bpf: Sanitize colons in traffic monitor pcap
 filenames

The traffic monitor's encode_test_name() only sanitizes '/' and ' '
characters from test/subtest names when constructing pcap log filenames.
The net_timestamping test has subtests with colons in their names (e.g.,
"INET4: bpf timestamping"), producing filenames like:

  packets-133-0-net_timestamping__INET4:_bpf_timestamping-net_timestamping_ns.log

GitHub Actions' upload-artifact@v4 rejects files containing colons,
double quotes, and other special characters, causing the artifact upload
step to fail. This makes every parallel test job (test_progs_parallel and
test_progs_no_alu32_parallel) fail in CI even when all tests pass.

Fix by using strpbrk() to replace '/', ' ', ':', and '"' characters with
underscores in a single pass, which is also simpler than the previous
two separate strchr() loops.

Fixes: f52403b6bfea ("selftests/bpf: Add traffic monitor functions.")
Generated-by: BPF CI Bot (claude-opus-4-6) <bot+bpf-ci@kernel.org>
---
 tools/testing/selftests/bpf/network_helpers.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index b82f572641b7..dc91a8eca4af 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -1142,9 +1142,7 @@ static void encode_test_name(char *buf, size_t len, const char *test_name, const
 		snprintf(buf, len, "%s__%s", test_name, subtest_name);
 	else
 		snprintf(buf, len, "%s", test_name);
-	while ((p = strchr(buf, '/')))
-		*p = '_';
-	while ((p = strchr(buf, ' ')))
+	while ((p = strpbrk(buf, " /:\"")))
 		*p = '_';
 }
 
-- 
2.53.0