[SIGNIFICANT] IPC channel capacity exhaustion under load #22

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opened 2026-05-11 10:52:01 +00:00 by thabeta · 1 comment

thabeta commented

2026-05-11 10:52:01 +00:00

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Problem

The IPC command channel has capacity 64, and the event channel has capacity 256. Under rapid command load:

The IPC handler's send().await on the command channel blocks when full
This blocks the IPC socket reader, causing TCP/Unix socket backpressure
Clients timeout waiting for responses
No mechanism exists to reject or drop commands under load

Impact

During high command volume (e.g., a script rapidly starting/stopping services, or a buggy client), the system becomes unresponsive. Clients hang and timeout, potentially leaving operations incomplete.

Files

crates/my_init_server/src/main.rs -- channel creation: mpsc::channel::<IpcCommand>(64), mpsc::channel(256)

Suggested Fix

Implement backpressure: return an error response immediately when the channel is full instead of blocking
Use try_send with a fallback error response
Add rate limiting on IPC connections

## Problem The IPC command channel has capacity 64, and the event channel has capacity 256. Under rapid command load: 1. The IPC handler's `send().await` on the command channel blocks when full 2. This blocks the IPC socket reader, causing TCP/Unix socket backpressure 3. Clients timeout waiting for responses 4. No mechanism exists to reject or drop commands under load ## Impact During high command volume (e.g., a script rapidly starting/stopping services, or a buggy client), the system becomes unresponsive. Clients hang and timeout, potentially leaving operations incomplete. ## Files - `crates/my_init_server/src/main.rs` -- channel creation: `mpsc::channel::<IpcCommand>(64)`, `mpsc::channel(256)` ## Suggested Fix - Implement backpressure: return an error response immediately when the channel is full instead of blocking - Use `try_send` with a fallback error response - Add rate limiting on IPC connections

thabeta added the

bug

label

2026-05-11 10:52:59 +00:00

salmaelsoly commented

2026-05-11 13:35:22 +00:00

Member

Classification: valid-bug — IPC channel capacity 64 blocks the socket reader when full, causing client timeouts and no mechanism to reject overload.

Confirmed by the issue description referencing crates/my_init_server/src/main.rs — the mpsc::channel::(64) and mpsc::channel(256) limits. When either channel is full, send().await blocks the IPC socket reader, creating backpressure against TCP/Unix clients. No try_send fallback or rate-limiting exists.

> Classification: valid-bug — IPC channel capacity 64 blocks the socket reader when full, causing client timeouts and no mechanism to reject overload. Confirmed by the issue description referencing crates/my_init_server/src/main.rs — the mpsc::channel::<IpcCommand>(64) and mpsc::channel(256) limits. When either channel is full, send().await blocks the IPC socket reader, creating backpressure against TCP/Unix clients. No try_send fallback or rate-limiting exists.