{"record":{"id":"ec510a55d8740e9d","repo":"cilium/cilium","slug":"making-blocks-for-programspec-s-w","errorCode":null,"errorMessage":"making Blocks for ProgramSpec %s: %w","messagePattern":"making Blocks for ProgramSpec (.+?): %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/datapath/loader/cache.go","lineNumber":241,"sourceCode":"\t\t\t)\n\t\t}\n\t\treturn nil, \"\", err\n\t}\n\n\tobj.path = path\n\n\tobj.spec, err = ebpf.LoadCollectionSpec(path)\n\tif err != nil {\n\t\treturn nil, \"\", fmt.Errorf(\"load eBPF ELF %s: %w\", path, err)\n\t}\n\n\t// Precompute the Blocks for each ProgramSpec in the CollectionSpec so\n\t// downstream callers don't need to compute them again. This is expensive to\n\t// run, so do it only once per compilation. Control flow isn't expected to\n\t// be changed after compilation.\n\tfor name, prog := range obj.spec.Programs {\n\t\tif _, err := analyze.MakeBlocks(prog.Instructions); err != nil {\n\t\t\treturn nil, \"\", fmt.Errorf(\"making Blocks for ProgramSpec %s: %w\", name, err)\n\t\t}\n\t\to.logger.Debug(\"Precomputed Blocks\", logfields.Object, name)\n\t}\n\n\treturn obj.spec.Copy(), hash, nil\n}\n","sourceCodeStart":223,"sourceCodeEnd":248,"githubUrl":"https://github.com/cilium/cilium/blob/ac7b90affa4baf0642e6685319d56907b3a73a6d/pkg/datapath/loader/cache.go#L223-L248","documentation":"After loading the collection spec, fetchOrCompile precomputes analyzer Blocks for every ProgramSpec via analyze.MakeBlocks. A per-program failure is wrapped as 'making Blocks for ProgramSpec <name>'. This indicates the control-flow/verifier pre-analysis of that program's instructions failed, usually a malformed or unsupported instruction sequence.","triggerScenarios":"analyze.MakeBlocks(prog.Instructions) returning an error for a given program name in the freshly loaded spec — e.g. unexpected jump targets or instruction encoding the analyzer cannot handle.","commonSituations":"Objects compiled with a newer/older clang producing instruction patterns the bundled analyzer doesn't understand; custom or patched BPF programs inserted into the template; version mismatch between loader and compiled object.","solutions":["Recompile the object with the supported clang/LLVM version","Check the named ProgramSpec against upstream template sources; revert local BPF patches","Update the agent (and its analyzer) to a version matching the object format","File/inspect an upstream issue if the stock template triggers it"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"// Compile objects with the toolchain version the analyzer supports\nif !supportedToolchain(clangVersion) {\n    return fmt.Errorf(\"clang %s unsupported for Blocks analysis\", clangVersion)\n}","typeGuard":null,"tryCatchPattern":"if err != nil && strings.Contains(err.Error(), \"making Blocks for ProgramSpec\") {\n    var specErr error\n    errors.As(err, &specErr)\n    log.Errorf(\"analyzer rejected program (%v); recompiling with pinned clang\", specErr)\n    invalidateCompiledCache()\n    return recompileAndReload(ctx)\n}","preventionTips":["Pin clang/LLVM to the version validated by the loader","Do not inject hand-patched BPF programs into the template pipeline","Keep the analyzer and compiler in the same release train","Test the full compile+load path after toolchain upgrades"],"tags":["bpf","analyzer","instructions","compile"],"backgroundTag":"bpf-block-analysis-failed","analyzedSha":"ac7b90affa4baf0642e6685319d56907b3a73a6d","analyzedAt":"2026-08-31T18:27:15.868Z","schemaVersion":2},"datasetVersion":"2026-08-31T19:17:28.585Z"}