{"record":{"id":"ee475b91685c70ca","repo":"astrid-runtime/astrid","slug":"fuse-service-control-response-exceeds-the-bounded","errorCode":null,"errorMessage":"FUSE service control response exceeds the bounded frame size","messagePattern":"FUSE service control response exceeds the bounded frame size","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"crates/astrid-storage-provider-fuse/src/control.rs","lineNumber":167,"sourceCode":"    let bytes = serde_json::to_vec(request)?;\n    if bytes.len() >= MAX_CONTROL_FRAME_BYTES {\n        bail!(\"FUSE control request exceeds the bounded frame size\");\n    }\n    stream.write_all(&bytes)?;\n    stream.write_all(b\"\\n\")?;\n    stream.flush()?;\n    let mut reader = BufReader::new(stream);\n    read_control_response(&mut reader)\n}\n\nfn read_control_response(reader: &mut BufReader<UnixStream>) -> Result<ControlResponse> {\n    let mut line = String::new();\n    let mut limited = reader.take((MAX_CONTROL_FRAME_BYTES + 1) as u64);\n    limited\n        .read_line(&mut line)\n        .context(\"read FUSE service control response\")?;\n    if line.len() > MAX_CONTROL_FRAME_BYTES {\n        bail!(\"FUSE service control response exceeds the bounded frame size\");\n    }\n    serde_json::from_str(&line).context(\"decode FUSE service control response\")\n}\n\n/// Remove the control endpoint and auto-created empty mountpoint.\npub(crate) fn cleanup_service_artifacts(\n    control_path: &Path,\n    mountpoint: &Path,\n    auto_created: bool,\n) -> Result<()> {\n    let _ = std::fs::remove_file(control_path);\n    if auto_created\n        && !mountinfo_contains(mountpoint)?\n        && std::fs::symlink_metadata(mountpoint).is_ok_and(|metadata| metadata.is_dir())\n        && std::fs::read_dir(mountpoint)?.next().is_none()\n    {\n        let _ = std::fs::remove_dir(mountpoint);\n    }","sourceCodeStart":149,"sourceCodeEnd":185,"githubUrl":"https://github.com/astrid-runtime/astrid/blob/affd8760f44190dbdfbec23403f4c4b642c33112/crates/astrid-storage-provider-fuse/src/control.rs#L149-L185","documentation":"This error means the response line read from the FUSE service control socket was longer than the 64 KiB `MAX_CONTROL_FRAME_BYTES` bound. The reader uses `take(MAX + 1)` so oversized responses are detected rather than read unboundedly, and the library refuses to decode a frame that violates the protocol. It is thrown from `read_control_response` in crates/astrid-storage-provider-fuse/src/control.rs:167 before `serde_json::from_str` is attempted.","triggerScenarios":"The detached FUSE service wrote a control response whose single newline-delimited line exceeds 65536 bytes; the read is invoked via `call_control`.","commonSituations":"A buggy or mismatched-version service serializing a huge failure payload (e.g. embedding a full stack trace or dump); a peer that never terminates lines, causing the take() limit to fill without a newline; hostile/broken socket peer sending garbage.","solutions":["Inspect what the FUSE service is writing to the control socket; fix oversized response payloads at the service side.","Ensure client and service use the same crate version so MAX_CONTROL_FRAME_BYTES and response shape agree.","Check that the service terminates every response with a newline (the frame protocol requires it).","If responses legitimately need more room, raise the bound on both sides deliberately."],"exampleFix":"// service-side: keep responses small\n// before\nControlResponse::Failure { code, message: format!(\"{huge_debug_dump}\") }\n// after\nControlResponse::Failure { code, message: truncate(&huge_debug_dump, 1024) }","handlingStrategy":"try-catch","validationCode":null,"typeGuard":"fn is_oversize(line: &str) -> bool { line.len() > 64 * 1024 }","tryCatchPattern":"match call_control(&sock, &req) {\n    Err(e) if e.to_string().contains(\"exceeds the bounded frame size\") => {\n        // restart service / shrink response, then retry\n    }\n    r => r?,\n}","preventionTips":["Keep control responses small (truncate messages, avoid embedding dumps)","Always terminate response frames with a newline","Pin client and service to the same crate version"],"tags":["fuse","ipc","payload-too-large","response"],"backgroundTag":"payload-too-large","analyzedSha":"affd8760f44190dbdfbec23403f4c4b642c33112","analyzedAt":"2026-09-09T21:28:12.402Z","contentChangedAt":"2026-09-09T21:28:12.402Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}