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GeezerVison is showing github.com — fix(profiler): reset ThreadContinuousScheduler lock after fork by BetterAndBetterII · Pull Request #7275 · getsentry/sentry-python

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BetterAndBetterII commented Aug 27, 2026

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Summary

ThreadContinuousScheduler.lock can be inherited locked across os.fork(). The holding thread does not exist in the child, so ensure_running can deadlock forever when it tries to acquire the lock.

This mirrors the Monitor fix from #6159: register an os.register_at_fork(after_in_child=...) hook (via weakref.WeakMethod) that reinitialises the lock and clears the inherited thread / pid / running / buffer so the child starts clean.

Scope is deliberately limited to ThreadContinuousScheduler (#6165). SessionFlusher / BackgroundWorker (#6164) are left alone.

Test plan

python -m pytest tests/profiler/test_continuous_profiler.py::test_thread_continuous_scheduler_lock_reset_in_child_after_fork -v
RED without the hook (child exits 1), GREEN with it (child exits 0)

Fixes #6165

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          fix(profiler): reset ThreadContinuousScheduler lock after fork

f2e4da4

If os.fork() runs while ThreadContinuousScheduler.lock is held, the child
inherits a locked lock with no owner and ensure_running can deadlock.
Mirror the Monitor getsentry#6159 pattern: register_at_fork after_in_child reset.

Fixes getsentry#6165

BetterAndBetterII requested a review from a team as a code owner

August 27, 2026 19:52

sentry-junior Bot mentioned this pull request

Nov 9, 2026

ref(profiling): Remove unused ContinuousScheduler.pause stub #8224

Merged

sentrivana pushed a commit that referenced this pull request

Nov 9, 2026


          ref(profiling): Remove unused ContinuousScheduler.pause stub (#8224)

3b49faf

### Description

Removes `ContinuousScheduler.pause()` from
`sentry_sdk/profiler/continuous_profiler.py` (3 lines). It's a stub that
only raises `NotImplementedError`, and nothing implements it or calls
it.

#2830 (Jun 2024, "Introduce continuous profiling mode") added it next to
`ensure_running()` and `teardown()`. Unlike those two, no subclass ever
overrode it, and the SDK never called it. The stub makes it look like
the continuous profiler can be paused, but it can't.

**Evidence**
- `git grep -nw pause` on `master` finds only the definition. Nothing in
`sentry_sdk/`, `tests/`, `scripts/` or `docs/` refers to it.
- `ThreadContinuousScheduler` and `GeventContinuousScheduler`, the only
subclasses, override `ensure_running()` and `teardown()` but not
`pause()`.
- `git log -S "def pause"` finds only #2830. `git log -S ".pause("`
across `sentry_sdk` and `tests` finds no commits, so it has never had a
caller.
- `ContinuousScheduler` isn't exported from `sentry_sdk.profiler`
(`__all__` lists only the transaction-profiler schedulers) and isn't
documented.
- No open PR or issue mentions it. #7275 also touches
`continuous_profiler.py`, but in different hunks
(`ThreadContinuousScheduler.__init__`).

**Why it's safe**
- `ContinuousScheduler` is an internal class. The method is unreachable,
so behavior doesn't change, and no public API or documented behavior is
affected.

**Checks**
- `uv run ruff check` / `ruff format --check` on `sentry_sdk/profiler`:
clean
- `uv run --group typing mypy sentry_sdk`: no issues
- `TESTPATH=tests/profiler uv run tox -e py3.14-common`: 106 passed, 69
skipped. The skipped tests are the gevent cases, which need gevent
installed.

#### Issues
None. Found by the weekly sentry-python removal scout.

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Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>

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Introduce fork-safety to ThreadContinuousScheduler

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