feat(crashtracking): GOT patch sigaction

[gyuheon0h]

bringing feat(crashtracking): GOT patch sigaction back

What does this PR do?

Intercepts sigaction calls with hook_symbol GOT patching so the crashtracker can detect when application code overwrites a monitored signal handler after initialization.

The hook covers all callers including the statically-linked test binary; internal sigaction calls from chain_signal_handler (which runs inside the signal handler) are safe because SIG_DFL/SIG_IGN handlers are filtered out before any async work is attempted (this is done before the hook_symbol anyways), and the hook always forwards using the stored original function pointer rather than through a GOT entry so there.

Motivation

Some runtimes may overwrite our handlers. It would be good to know when this is happening.

Additional Notes

This is a stacked PR. This change is minimal -- just adding the patch, and flipping a flag that isnt read anywhere. Sending actual telemetry is done feat(crashtracking): send telemetry if instrumented application sigactions our signal

How to test the change?

Describe here in detail how the change can be validated.

[gyuheon0h]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat(crashtracking)!: API to unpatch crashtracker GOT patches #2492
• feat(crashtracking): GOT patch sigaction #2496 👈 (View in Graphite)
• feat(gotter)!: unpatch symbol functionality #2342
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

📚 Documentation Check Results

⚠️ 1113 documentation warning(s) found

📦 libdd-crashtracker - 1113 warning(s)

---

Updated: 2026-09-11 18:31:20 UTC | Commit: d6edc74 | missing-docs job results

[github-actions]

🔒 Cargo Deny Results

✅ No issues found!

📦 libdd-crashtracker - ✅ No issues

---

Updated: 2026-09-11 18:30:47 UTC | Commit: d6edc74 | dependency-check job results

[datadog-prod-us1-4]

✅ All CI checks and tests passed.

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 63.24%
• Overall Coverage: 77.79% (+0.03%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 3dff449 | Docs | View more details | Give us feedback!}

[pr-commenter]

Benchmarks

Comparison

Benchmark execution time: 2026-09-11 18:40:30

Comparing candidate commit 3dff449 in PR branch gyuheon0h/got-patch-sigaction with baseline commit b5deb14 in branch gyuheon0h/unpatch-gotter.

📊 Benchmarking dashboard

Found 0 performance improvements and 0 performance regressions! Performance is the same for 1 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

Candidate

Candidate benchmark details

Group 1

cpu_model	git_commit_sha	git_commit_date	git_branch
Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz	3dff449	1789151263	gyuheon0h/got-patch-sigaction

scenario	metric	min	mean ± sd	median ± mad	p75	p95	p99	max	peak_to_median_ratio	skewness	kurtosis	cv	sem	runs	sample_size
receiver_entry_point/report/2644	execution_time	6.289ms	6.350ms ± 0.039ms	6.341ms ± 0.023ms	6.370ms	6.434ms	6.454ms	6.456ms	1.82%	0.891	0.214	0.62%	0.003ms	1	200

scenario	metric	95% CI mean	Shapiro-Wilk pvalue	Ljung-Box pvalue (lag=1)	Dip test pvalue
receiver_entry_point/report/2644	execution_time	[6.345ms; 6.355ms] or [-0.086%; +0.086%]	None	None	None

Baseline

Baseline benchmark details

Group 1

cpu_model	git_commit_sha	git_commit_date	git_branch
Intel(R) Xeon(R) Platinum 8175M CPU @ 2.50GHz	b5deb14	1789151262	gyuheon0h/unpatch-gotter

scenario	metric	min	mean ± sd	median ± mad	p75	p95	p99	max	peak_to_median_ratio	skewness	kurtosis	cv	sem	runs	sample_size
receiver_entry_point/report/2644	execution_time	6.284ms	6.373ms ± 0.025ms	6.372ms ± 0.013ms	6.385ms	6.419ms	6.425ms	6.488ms	1.83%	0.361	2.748	0.40%	0.002ms	1	200

scenario	metric	95% CI mean	Shapiro-Wilk pvalue	Ljung-Box pvalue (lag=1)	Dip test pvalue
receiver_entry_point/report/2644	execution_time	[6.369ms; 6.377ms] or [-0.055%; +0.055%]	None	None	None

[dd-octo-sts]

Artifact Size Benchmark Report

aarch64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.a	96.01 MB	96.02 MB	+0% (+7.15 KB) 👌
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.so	9.02 MB	9.02 MB	0% (0 B) 👌

aarch64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.so	12.19 MB	12.19 MB	+0% (+1.10 KB) 👌
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.a	107.42 MB	107.42 MB	+0% (+6.87 KB) 👌

libdatadog-x64-windows

Artifact	Baseline	Commit	Change
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.dll	29.04 MB	29.04 MB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.lib	96.08 KB	96.08 KB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.pdb	191.77 MB	191.77 MB	0% (0 B) 👌
/libdatadog-x64-windows/debug/static/datadog_profiling_ffi.lib	818.18 MB	818.18 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.dll	9.69 MB	9.69 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.lib	96.08 KB	96.08 KB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.pdb	27.51 MB	27.51 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/static/datadog_profiling_ffi.lib	55.57 MB	55.57 MB	0% (0 B) 👌

libdatadog-x86-windows

Artifact	Baseline	Commit	Change
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.dll	25.41 MB	25.41 MB	0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.lib	97.58 KB	97.58 KB	0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.pdb	197.08 MB	197.08 MB	0% (0 B) 👌
/libdatadog-x86-windows/debug/static/datadog_profiling_ffi.lib	800.48 MB	800.48 MB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.dll	7.51 MB	7.51 MB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.lib	97.58 KB	97.58 KB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.pdb	29.63 MB	29.63 MB	0% (0 B) 👌
/libdatadog-x86-windows/release/static/datadog_profiling_ffi.lib	52.55 MB	52.55 MB	0% (0 B) 👌

x86_64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.a	85.97 MB	85.97 MB	+0% (+5.32 KB) 👌
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.so	10.03 MB	10.03 MB	0% (0 B) 👌

x86_64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.a	101.85 MB	101.86 MB	+0% (+5.28 KB) 👌
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.so	12.25 MB	12.25 MB	+0% (+896 B) 👌