Stack overflow during shutdown of `BatchLogProcessor`

[zheilbron]

opentelemetry_sdk version: 0.29

If I enable debug logging for the crate I see the following:

2025-06-09T19:45:59.696986Z DEBUG opentelemetry_sdk:  name="BatchLogProcessor.ExportingDueToForceFlush"
2025-06-09T19:45:59.697019Z DEBUG opentelemetry-otlp:  name="TonicsLogsClient.CallingExport"
2025-06-09T19:45:59.697580Z DEBUG opentelemetry_sdk:  name="LoggerProvider.ShutdownInvokedByUser"
2025-06-09T19:45:59.697604Z DEBUG opentelemetry_sdk:  name="BatchLogProcessor.ExportingDueToShutdown"
2025-06-09T19:45:59.697625Z DEBUG opentelemetry-otlp:  name="TonicsLogsClient.CallingExport"
2025-06-09T19:45:59.698071Z DEBUG opentelemetry_sdk:  name="BatchLogProcessor.ThreadExiting" reason="ShutdownRequested"
2025-06-09T19:45:59.698081Z DEBUG opentelemetry_sdk:  name="BatchLogProcessor.ThreadStopped"

thread 'OpenTelemetry.Traces.BatchProcessor' has overflowed its stack
fatal runtime error: stack overflow

Note without debug logging, I see that other threads can also trigger the SO:

...
thread 'tokio-runtime-worker' has overflowed its stack
fatal runtime error: stack overflow
...

This makes me think that it has something to do with the the last caller to emit a log and/or a full channel, but that's just a guess.

The code that triggers it:

// let p: SdkLoggerProvider ...
...
p.force_flush().ok();
p.shutdown().ok();

Does not happen if i remove shutdown.

Possibly related to #2897.

[cijothomas]

can you share the full setup code?

[zheilbron]

Here's the (hopefully) relevant section of code:

        let logger_provider = SdkLoggerProvider::builder()
            .with_resource(resource.clone())
            .with_batch_exporter(
                LogExporter::builder()
                    .with_tonic()
                    .with_endpoint(otlp_endpoint)
                    .build()?,
            )
            .build();
        let tracer_provider = SdkTracerProvider::builder()
            .with_resource(resource.clone())
            .with_batch_exporter(
                SpanExporter::builder()
                    .with_tonic()
                    .with_endpoint(otlp_endpoint)
                    .build()?,
            )
            .build();
        let log_bridge = OpenTelemetryTracingBridge::new(&logger_provider);
        closables.push(Box::new({
            let p = logger_provider.clone();
            move || {
                p.force_flush().ok();
                p.shutdown().ok();
            }
        }));
        closables.push(Box::new({
            let p = tracer_provider.clone();
            move || {
                p.force_flush().ok();
                p.shutdown().ok();
            }
        }));
        let tracer = tracer_provider.tracer("global");
        (
            Some(log_bridge),
            Some(tracing_opentelemetry::layer().with_tracer(tracer)),
        )

The closables are closed at the end of the program during the Drop call of the struct that holds them.