CWS: synthesize cgroup_write event for CLONE_INTO_CGROUP migrations

[safchain]

The cgroup_write tracepoint only fires on writes to cgroup.procs, so cgroup migrations performed via clone3 with CLONE_INTO_CGROUP go undetected. When setProcessContext sees a kernel-reported cgroup inode that differs from the cached entry, refresh the resolvers and emit a synthesized cgroup_write related event as a fallback.

Move the related-event callback closures from per-event locals to function-value fields on EBPFProbe, bound once in NewEBPFProbe. This drops per-event closure allocations on the handleEvent hot path and lets internal helpers (setProcessContext, handleRegularEvent, etc.) drop the callback parameter from their signatures. A deferred drain returns pooled related events to the pool on every exit path so early returns no longer leak pool entries.

Collapses TestCGroupPropagation into a table-driven test with two subtests: the original open-event attribution check, and a new cgroup-write-fallback subtest exercising the synthesized event.

What does this PR do?

Motivation

Describe how you validated your changes

Additional Notes

[datadog-official]

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 2 Pipeline jobs failed

DataDog/datadog-agent | kmt_run_secagent_tests_x64: [rocky_8.5, cws_host]     

🛟 This job is unlikely to succeed on retry. Please review your pipeline configuration.

Test failures in pkg/security due to unsupported kernel version: CLONE_INTO_CGROUP requires kernel >= 5.7 at cgroup_test.go:213.

DataDog/datadog-agent | oracle: [21.3.0-xe]     

🛟 This job is unlikely to succeed on retry. Please review your pipeline configuration.

Failed to ping oracle instance: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

ℹ️ Info

🎯 Code Coverage (details)
• Patch Coverage: 14.89%
• Overall Coverage: 50.35% (-0.00%)

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[dd-octo-sts]

Files inventory check summary

File checks results against ancestor fa1a5b06:

Results for datadog-agent_7.81.0~devel.git.143.d7aac68.pipeline.114546230-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor fa1a5b0
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	+4.0 KiB (0.00% increase, -0.07% of buffer)	745.165 → 745.169 → 750.800
✅	agent_rpm_amd64	+4.0 KiB (0.00% increase, -0.07% of buffer)	745.149 → 745.153 → 750.770
✅	agent_rpm_arm64_fips	+4.0 KiB (0.00% increase, -0.32% of buffer)	683.640 → 683.644 → 684.870
✅	agent_suse_amd64	+4.0 KiB (0.00% increase, -0.07% of buffer)	745.149 → 745.153 → 750.770
✅	agent_suse_arm64_fips	+4.0 KiB (0.00% increase, -0.32% of buffer)	683.640 → 683.644 → 684.870
✅	docker_agent_amd64	+4.0 KiB (0.00% increase, -0.38% of buffer)	805.306 → 805.310 → 806.340
✅	docker_agent_jmx_amd64	+3.99 KiB (0.00% increase, -0.47% of buffer)	996.226 → 996.230 → 997.060

25 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64_fips	702.928 MiB
✅	agent_heroku_amd64	310.122 MiB
✅	agent_rpm_amd64_fips	702.911 MiB
✅	agent_rpm_arm64	722.712 MiB
✅	agent_suse_amd64_fips	702.911 MiB
✅	agent_suse_arm64	722.712 MiB
✅	docker_agent_arm64	807.690 MiB
✅	docker_agent_jmx_arm64	987.389 MiB
✅	docker_cluster_agent_amd64	206.995 MiB
✅	docker_cluster_agent_arm64	220.952 MiB
✅	docker_cws_instrumentation_amd64	7.154 MiB
✅	docker_cws_instrumentation_arm64	6.689 MiB
✅	docker_dogstatsd_amd64	39.487 MiB
✅	docker_dogstatsd_arm64	37.690 MiB
✅	docker_host_profiler_amd64	302.187 MiB
✅	docker_host_profiler_arm64	313.675 MiB
✅	dogstatsd_deb_amd64	30.143 MiB
✅	dogstatsd_deb_arm64	28.268 MiB
✅	dogstatsd_rpm_amd64	30.143 MiB
✅	dogstatsd_suse_amd64	30.143 MiB
✅	iot_agent_deb_amd64	44.578 MiB
✅	iot_agent_deb_arm64	41.535 MiB
✅	iot_agent_deb_armhf	42.243 MiB
✅	iot_agent_rpm_amd64	44.578 MiB
✅	iot_agent_suse_amd64	44.578 MiB

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 2427bb77-3de9-427a-97a7-fc385d0c2f02

Baseline: fa1a5b0
Comparison: d7aac68
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	-1.85	[-4.72, +1.02]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	tcp_syslog_to_blackhole	ingress throughput	+2.40	[+2.17, +2.62]	1	Logs
➖	otlp_ingest_logs	memory utilization	+0.44	[+0.34, +0.54]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	+0.25	[+0.09, +0.40]	1	Logs
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.22	[-0.02, +0.45]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.20	[+0.15, +0.25]	1	Logs
➖	ddot_metrics_sum_delta	memory utilization	+0.08	[-0.12, +0.27]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	+0.07	[+0.01, +0.13]	1	Logs bounds checks dashboard
➖	file_to_blackhole_0ms_latency	egress throughput	+0.04	[-0.49, +0.57]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.03	[-0.37, +0.44]	1	Logs
➖	ddot_metrics	memory utilization	+0.01	[-0.19, +0.21]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.20, +0.21]	1	Logs
➖	otlp_ingest_metrics	memory utilization	-0.00	[-0.16, +0.16]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	-0.02	[-0.23, +0.19]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.02	[-0.14, +0.10]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.02	[-0.17, +0.12]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.04	[-0.48, +0.40]	1	Logs
➖	quality_gate_idle	memory utilization	-0.05	[-0.10, -0.00]	1	Logs bounds checks dashboard
➖	docker_containers_memory	memory utilization	-0.09	[-0.19, +0.01]	1	Logs
➖	file_tree	memory utilization	-0.16	[-0.21, -0.12]	1	Logs
➖	quality_gate_metrics_logs	memory utilization	-0.57	[-0.81, -0.32]	1	Logs bounds checks dashboard
➖	ddot_logs	memory utilization	-0.68	[-0.75, -0.61]	1	Logs
➖	quality_gate_logs	% cpu utilization	-1.40	[-2.40, -0.41]	1	Logs bounds checks dashboard
➖	docker_containers_cpu	% cpu utilization	-1.85	[-4.72, +1.02]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	715 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	245.40MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	719 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.16GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.20GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.17GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.18GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	146.49MiB ≤ 147MiB	bounds checks dashboard
✅	quality_gate_idle	total_bytes_received	10/10	740.12KiB ≤ 819.20KiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	2 ≤ 4	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	431.34MiB ≤ 495MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	total_bytes_received	10/10	1.12MiB ≤ 1.25MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	176.92MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_logs	total_bytes_received	10/10	264.37MiB ≤ 292MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	341.16 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	383.34MiB ≤ 430MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	total_bytes_received	10/10	0.94GiB ≤ 1.04GiB	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.