{"record":{"id":"69ee63452ed45d8f","repo":"pranshuparmar/witr","slug":"no-process-ancestry-found","errorCode":null,"errorMessage":"no process ancestry found","messagePattern":"no process ancestry found","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/proc/ancestry.go","lineNumber":35,"sourceCode":"\t\t\tbreak // loop protection\n\t\t}\n\t\tseen[current] = true\n\n\t\tp, err := ReadProcess(current)\n\t\tif err != nil {\n\t\t\tbreak\n\t\t}\n\n\t\tchain = append(chain, p)\n\n\t\tif p.PPID == 0 || p.PID == 1 {\n\t\t\tbreak\n\t\t}\n\t\tcurrent = p.PPID\n\t}\n\n\tif len(chain) == 0 {\n\t\treturn nil, fmt.Errorf(\"no process ancestry found\")\n\t}\n\n\t// Reverse the chain to get root\n\tfor i, j := 0, len(chain)-1; i < j; i, j = i+1, j-1 {\n\t\tchain[i], chain[j] = chain[j], chain[i]\n\t}\n\n\treturn chain, nil\n}\n","sourceCodeStart":17,"sourceCodeEnd":45,"githubUrl":"https://github.com/pranshuparmar/witr/blob/dc4fa1da82d3e266fcbd928641b4f30b3077c64f/internal/proc/ancestry.go#L17-L45","documentation":"ResolveAncestry walks the parent chain (pid -> ppid) building a chain of ancestors. If the walk terminates without collecting a single entry (len(chain)==0) — i.e. the starting process could not be found or its parent link could not be read — it returns 'no process ancestry found'. The initial pid itself counts as a chain entry only when its record is readable.","triggerScenarios":"Calling ResolveAncestry with a pid that no longer exists; the process table lookup for the root pid fails immediately (permission denied or zombie reaped) so the loop body never appends to chain.","commonSituations":"Race where a short-lived process exits before the ancestry walk starts; querying a child of a containerized/hidden process from outside its namespace; insufficient privileges to read another user's process records; integration tests using an already-reaped pid.","solutions":["Verify the starting pid is alive before calling (kill -0 <pid>).","Re-run with elevated privileges if the process belongs to another user or namespace.","Retry shortly — if the pid is being reaped, a fresh snapshot may resolve; otherwise treat as permanent.","Pass a valid, existing pid from a fresh process listing instead of a cached one."],"exampleFix":"// before\nchain, err := proc.ResolveAncestry(pid) // pid may have exited\n// after\nif err := syscall.Kill(pid, 0); err != nil {\n    return fmt.Errorf(\"pid %d already exited; cannot resolve ancestry\", pid)\n}\nchain, err := proc.ResolveAncestry(pid)","handlingStrategy":"validation","validationCode":"func pidAlive(pid int) bool {\n    return syscall.Kill(pid, 0) == nil\n}\nif !pidAlive(pid) {\n    return fmt.Errorf(\"pid %d is gone; cannot resolve ancestry\", pid)\n}","typeGuard":null,"tryCatchPattern":"chain, err := proc.ResolveAncestry(pid)\nif err != nil {\n    if strings.Contains(err.Error(), \"no process ancestry found\") {\n        log.Printf(\"pid %d vanished before ancestry walk; retrying once\", pid)\n        chain, err = proc.ResolveAncestry(pid)\n    }\n    if err != nil { return err }\n}","preventionTips":["Check pid liveness (signal 0) immediately before the ancestry walk.","Retry once on short-lived processes — they often exit mid-lookup.","Run with privileges covering the target's user/namespace.","Use pids from a fresh process snapshot, not cached values."],"tags":["process-inspection","ancestry","race-condition","not-found"],"backgroundTag":"process-ancestry-not-found","analyzedSha":"dc4fa1da82d3e266fcbd928641b4f30b3077c64f","analyzedAt":"2026-09-01T12:17:08.767Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T15:18:49.778Z"}