[PROF-11003] Fix unsafe initialization when using profiler with otel tracing

[ivoanjo]

What does this PR do?

This PR fixes two issues in the profiler's support for reading from the opentelemetry ("otel") context:

1. If during the initialization of our otel reading code an exception was raised, we tried to rescue it but did not properly clean it up so it could still confuse the app/cause weird behaviors

2. Initialization of the otel reading code could happen during an allocation sample, where it's not safe to run random Ruby code (including throwing exceptions)

Motivation:

I suspect these issues may be linked to a customer crash:

[BUG] unexpected situation - recordd:1 current:0

-- C level backtrace information -------------------------------------------
ruby(rb_print_backtrace+0x11) [0x55ba03ccf90f] vm_dump.c:820
ruby(rb_vm_bugreport) vm_dump.c:1151
ruby(bug_report_end+0x0) [0x55ba03e91607] error.c:1042
ruby(rb_bug_without_die) error.c:1042
ruby(die+0x0) [0x55ba03ac0998] error.c:1050
ruby(rb_bug) error.c:1052
ruby(disallow_reentry+0x0) [0x55ba03ab6dcc] vm_sync.c:226
ruby(rb_ec_vm_lock_rec_check+0x1a) [0x55ba03cb17aa] eval_intern.h:144
ruby(rb_ec_tag_state) eval_intern.h:155
ruby(rb_vm_exec) vm.c:2484
ruby(vm_invoke_proc+0x201) [0x55ba03cb62b1] vm.c:1509
ruby(rb_vm_invoke_proc+0x33) [0x55ba03cb65d3] vm.c:1728
ruby(thread_do_start_proc+0x176) [0x55ba03c63516] thread.c:598
ruby(thread_do_start+0x12) [0x55ba03c648a2] thread.c:615
ruby(thread_start_func_2) thread.c:672
ruby(nt_start+0x107) [0x55ba03c65137] thread_pthread.c:2187
/lib/x86_64-linux-gnu/libpthread.so.0(start_thread+0xd9) [0x7ff360b66609]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7ff360a70353]

...but I could not reproduce it myself. Nevertheless, the things being fixed were still definitely bugs ;)

Change log entry

Yes. Fix unsafe initialization when using profiler with otel tracing

Additional Notes:

N/A

How to test the change?

This change includes test coverage (took longer than the fixes to code :P)

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2024-12-05 14:06:54 UTC}

[datadog-datadog-prod-us1]

Datadog Report

Branch report: ivoanjo/prof-11003-fix-profiler-otel-initialization
Commit report: 47b1706
Test service: dd-trace-rb

✅ 0 Failed, 22411 Passed, 1459 Skipped, 5m 51.73s Total Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-12-05 12:48:45

Comparing candidate commit 47b1706 in PR branch ivoanjo/prof-11003-fix-profiler-otel-initialization with baseline commit f354358 in branch master.

Found 0 performance improvements and 1 performance regressions! Performance is the same for 30 metrics, 2 unstable metrics.

scenario:profiler - sample timeline=false

• 🟥 throughput [-0.511op/s; -0.463op/s] or [-7.901%; -7.172%]

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.75%. Comparing base (f354358) to head (47b1706).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4195      +/-   ##
==========================================
- Coverage   97.76%   97.75%   -0.01%     
==========================================
  Files        1357     1357              
  Lines       81890    81914      +24     
  Branches     4164     4164              
==========================================
+ Hits        80060    80076      +16     
- Misses       1830     1838       +8     

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