Fix stack walking alignment issues causing ASAN violations #362
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- Add frame size validation and alignment checks in stackWalker - Replace raw pointer dereferences with SafeAccess::load in signal-critical paths - Add deoptimization check before walking compiled frames - Enable ASAN/TSAN configs in Docker test script - Document Docker-based testing workflow in CLAUDE.md 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
CI Test ResultsRun: #21863805109 | Commit:
Status Overview
Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled Summary
Updated: 2026-02-10 12:22:23 UTC |
jbachorik
changed the title
- Use pattern matching to download all failures-* artifacts - Add merge-multiple flag to combine artifacts - Add graceful handling for missing failure files - Fix JSON format in Slack webhook payload - Add webhook existence check before posting 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
MAX_FRAME_SIZE is in StackWalkValidation namespace, need explicit qualification before using declarations. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
jbachorik
changed the title
Scan-Build Report
Bug Summary
Reports
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Benchmarks [aarch64 memleak,alloc]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 19 metrics, 0 unstable metrics. |
Benchmarks [x86_64 alloc]Parameters
See matching parameters
SummaryFound 1 performance improvements and 0 performance regressions! Performance is the same for 15 metrics, 22 unstable metrics.
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Benchmarks [aarch64 wall]Parameters
See matching parameters
SummaryFound 1 performance improvements and 0 performance regressions! Performance is the same for 17 metrics, 20 unstable metrics.
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Benchmarks [x86_64 cpu,wall,alloc,memleak]Parameters
See matching parameters
SummaryFound 1 performance improvements and 0 performance regressions! Performance is the same for 14 metrics, 23 unstable metrics.
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Benchmarks [aarch64 cpu]Parameters
See matching parameters
SummaryFound 0 performance improvements and 1 performance regressions! Performance is the same for 16 metrics, 21 unstable metrics.
|
Benchmarks [x86_64 memleak,alloc]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 15 metrics, 23 unstable metrics. |
Benchmarks [x86_64 cpu]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 15 metrics, 23 unstable metrics. |
Benchmarks [aarch64 cpu,wall]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 17 metrics, 21 unstable metrics. |
Benchmarks [aarch64 memleak]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 15 metrics, 23 unstable metrics. |
Benchmarks [aarch64 cpu,wall,alloc,memleak]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 15 metrics, 23 unstable metrics. |
Benchmarks [aarch64 alloc]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 16 metrics, 22 unstable metrics. |
Benchmarks [x86_64 wall]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 14 metrics, 24 unstable metrics. |
Benchmarks [x86_64 memleak]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 14 metrics, 24 unstable metrics. |
Benchmarks [x86_64 cpu,wall]Parameters
See matching parameters
SummaryFound 0 performance improvements and 0 performance regressions! Performance is the same for 14 metrics, 24 unstable metrics. |
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What does this PR do?:
Fixes critical alignment issues in stack walking that were causing ASAN violations during nightly runs.
Primary fixes:
Supporting improvements:
Motivation:
A recent nightly ASAN run identified alignment violations in stack walking - https://github.com/DataDog/java-profiler/actions/runs/21851118212/job/63057859995#step:9:363
The issue occurred when sp (stack pointer) was not properly aligned before being dereferenced as a pointer. Without alignment checks, the profiler could attempt to read from misaligned addresses, causing:
This PR systematically adds alignment validation at all pointer dereference sites in the stack walking code paths (walkVM, walkDwarf), ensuring memory is only accessed at properly aligned boundaries.
Additional Notes:
The alignment checks follow the pattern already established in the codebase but weren't consistently applied across all unwinding paths. Frame size validation prevents walking beyond reasonable frame boundaries (MAX_FRAME_SIZE_WORDS = 32768 words).
How to test the change?:
./gradlew testAsan./utils/run-docker-tests.sh --config=asan --jdk=21For Datadog employees:
@DataDog/security-design-and-guidance.