{"record":{"id":"5ded8cf23fb8906b","repo":"firecracker-microvm/firecracker","slug":"balloon-invalid-queue-id-qidx","errorCode":null,"errorMessage":"balloon: invalid queue id: {qidx}","messagePattern":"balloon: invalid queue id: (.+?)","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/vmm/src/devices/virtio/balloon/device.rs","lineNumber":659,"sourceCode":"\n            queue.add_used(head.index, 0)?;\n            needs_interrupt = true;\n        }\n\n        queue.advance_used_ring_idx();\n\n        if needs_interrupt {\n            self.signal_used_queue(idx)?;\n        }\n\n        Ok(())\n    }\n\n    pub(crate) fn signal_used_queue(&self, qidx: usize) -> Result<(), BalloonError> {\n        self.interrupt_trigger()\n            .trigger(VirtioInterruptType::Queue(\n                qidx.try_into()\n                    .unwrap_or_else(|_| panic!(\"balloon: invalid queue id: {qidx}\")),\n            ))\n            .map_err(|err| {\n                METRICS.event_fails.inc();\n                BalloonError::InterruptError(err)\n            })\n    }\n\n    /// Process device virtio queue(s).\n    pub fn process_virtio_queues(&mut self) -> Result<(), InvalidAvailIdx> {\n        if let Err(BalloonError::InvalidAvailIdx(err)) = self.process_inflate() {\n            return Err(err);\n        }\n        if let Err(BalloonError::InvalidAvailIdx(err)) = self.process_deflate_queue() {\n            return Err(err);\n        }\n\n        if self.free_page_hinting()\n            && let Err(BalloonError::InvalidAvailIdx(err)) = self.process_free_page_hinting_queue()","sourceCodeStart":641,"sourceCodeEnd":677,"githubUrl":"https://github.com/firecracker-microvm/firecracker/blob/cc535f035f3828b2c5bfc85276c5d394022ed220/src/vmm/src/devices/virtio/balloon/device.rs#L641-L677","documentation":"Error \"balloon: invalid queue id: {qidx}\" thrown in firecracker-microvm/firecracker.","triggerScenarios":"Thrown at src/vmm/src/devices/virtio/balloon/device.rs:664 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Ensure the queue index passed to the balloon device is within the number of queues the device exposes.","Verify virtio queue negotiation completed before signalling queue events."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"cc535f035f3828b2c5bfc85276c5d394022ed220","analyzedAt":"2026-08-19T05:27:02.517Z","contentChangedAt":"2026-08-19T05:27:02.517Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}