ThreadSanitizer data races

[rejuvenile]

How do you use Sentry?

Sentry SaaS (sentry.io)

SDK version

0.37.0

Steps to reproduce

Run simple Rust unit tests with Sentry and ThreadSanitizer enabled, e.g. -Zsanitizer=thread.

Expected result

No TSan races.

Actual result

...
SUMMARY: ThreadSanitizer: data race external/rules_rust++crate+crates__sentry-core-0.37.0/src/session.rs:229:28 in sentry_core::session::session_impl::SessionFlusher::new::_$u7b$$u7b$closure$u7d$$u7d$::h9df72737faa3d066

...
SUMMARY: ThreadSanitizer: data race /rustc/d5b4c2e4f19b6d7037371cdaecc3cc2c701c68df/library/alloc/src/sync.rs:2633:13 in _$LT$alloc..sync..Arc$LT$T$C$A$GT$$u20$as$u20$core..ops..drop..Drop$GT$::drop::h1fc845397ad95c9f

[lcian]

Thanks for reporting!
I'm able to reproduce this, let me look into it further.

[lcian]

@rejuvenile Could you please share the code for a unit test that triggers the race?

[lcian]

With this test I'm not getting any sentry_core::session::session_impl::SessionFlusher entries as you posted.

#[test]
fn test_init() {
    let _guard = sentry::init(("https://my-dsn@o0.ingest.us.sentry.io/0", sentry::ClientOptions { auto_session_tracking: true, session_mode: sentry::SessionMode::Application, ..Default::default() }));

    sentry::capture_message("whatever", sentry::Level::Error);
}

[lcian]

Ok actually I think I'm getting it, with just the init snippet and no capture_message I now get SessionFlusher entries

[lcian]

This seems to happen only when the SDK is initialized and then immediately shut down.

[lcian]

Looked into this for a while, turns out that no race is detected when using -Zbuild-std.
For the record, here's my test setup https://github.com/lcian/sentry-samples-rust/tree/main/tsan
@rejuvenile please reopen the issue if there's other races detected even with -Zbuild-std, including the test code that triggers them. Thanks.