Mitigating VMMethod::id() crash

[zhengyu123]

What does this PR do?:
Mitigating VMMethod::id() crashes in latest release.

Motivation:
Currently, crash tracker report does not provide sufficient information to identify the root cause. While we are waiting for DataDog/dd-trace-java #10544 Preserve the function relative address when parsing a crash to gather more information to solve the mysteries, let's provide a mitigation for this crash.

Other than SafeAccesss inside VMMethod::id() method, VMMethod* can be invalid, e.g. points to unmapped memory, let's validates the memory before the access.

Additional Notes:

How to test the change?:
-Regular tests
-New gtest to verify new SafeAccess::isReadable()

For Datadog employees:

• If this PR touches code that signs or publishes builds or packages, or handles
  credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• This PR doesn't touch any of that.
• JIRA: PROF-13655

Unsure? Have a question? Request a review!

[dd-octo-sts]

Scan-Build Report

User:	runner@runnervmwffz4
Working Directory:	/home/runner/work/java-profiler/java-profiler/ddprof-lib/src/test/make
Command Line:	make -j4 all
Clang Version:	Ubuntu clang version 18.1.3 (1ubuntu1)
Date:	Fri Feb 6 14:45:40 2026

Bug Summary

Bug Type	Quantity	Display?
All Bugs	1
Unused code
Dead assignment	1

Reports

Bug Group	Bug Type ▾	File	Function/Method	Line	Path Length
Unused code	Dead assignment	libraryPatcher_linux.cpp	patch_library_unlocked	94	1

[dd-octo-sts]

CI Test Results

Run: #21754553104 | Commit: fc3bb4f | Duration: 14m 15s (longest job)

✅ All 40 test jobs passed

Status Overview

Platform	8	8-ibm	8-j9	8-libr	8-orcl	8-zing	11	11-j9	11-lib	11-zin	17	17-gra	17-j9	17-lib	17-zin	21	21-gra	21-lib	21-zin	25	25-gra	25-lib
glibc-aarch64/debug	-	-	✅	-	-	✅	-	✅	-	✅	✅	✅	✅	-	✅	✅	✅	-	✅	✅	✅	-
glibc-amd64/debug	✅	✅	✅	-	✅	✅	✅	✅	-	✅	✅	✅	✅	-	✅	✅	✅	-	✅	✅	✅	-
musl-aarch64/debug	-	-	-	✅	-	-	-	-	✅	-	-	-	-	✅	-	-	-	✅	-	-	-	✅
musl-amd64/debug	-	-	-	✅	-	-	-	-	✅	-	-	-	-	✅	-	-	-	✅	-	-	-	✅

Legend: ✅ passed | ❌ failed | ⚪ skipped | 🚫 cancelled

Summary

Metric	Value
Total jobs	40
Passed	40
Failed	0

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Updated: 2026-02-06 15:01:12 UTC

[pr-commenter]

Integration Tests

✅ All 40 integration tests passed

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