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fix(net): break tx loop on non-recoverable errors to prevent busy-loop #606

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fix(net): break tx loop on non-recoverable errors to prevent busy-loop #606

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fix(net): break tx loop on non-recoverable errors to prevent busy-loop
areporeporepo Mar 25, 2026
8e9d85d
fix(net): re-enable notifications before breaking tx loop
areporeporepo Apr 5, 2026
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6 changes: 5 additions & 1 deletion src/devices/src/virtio/net/worker.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -284,7 +284,11 @@ impl NetWorker {
Err(TxError::Backend(WriteError::NothingWritten)) => true,
Err(e) => {
log::error!("Failed to process tx: {e:?}");
false
// Re-enable notifications before breaking so the guest
// can still kick the TX queue on future descriptors.
let _ = self.tx_q.queue.enable_notification(&self.mem);
self.tx_has_deferred_frame = false;
break;
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@nirs nirs Apr 5, 2026

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I don't think this is right:

  • What would be the value of self.tx_has_deferred_frame after the break? before this change the value is false, which means we don't need to set up a timer.
  • Even if the value is false, this is not right since the code is not clear.
  • If we break here, we don't call tx_q.queue.enable_notification(&self.mem) which may not be correct. The current code always call tx_q.queue.enable_notification on each iteration.
  • There is no busy loop - I think the issue is wrong. The purpose of the worker is to write frames from the guest. If we we cannot write frames we should drop the fame, log an error and continue. In the worst case we will have unrecoverable error that will drop all frames and write lot of logs. There is nothing wrong about this, and it will make the issue easy to debug.

The issue was suggested by Gemini, and I opened it for discussion. I suggest to finish the discussion on the issue before making changes.

}
_ => false,
};
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