{"record":{"id":"d67fad0f449a7b44","repo":"NationalSecurityAgency/ghidra","slug":"error-disassemble-fn-is-null-nothing-i-can-do-n","errorCode":null,"errorMessage":"Error: disassemble_fn is NULL. Nothing I can do.\\n","messagePattern":"Error: disassemble_fn is NULL\\. Nothing I can do\\.\\\\n","errorType":"console","errorClass":null,"httpStatus":null,"severity":"error","filePath":"GPL/GnuDisassembler/src/gdis/c/disasm_1.c","lineNumber":454,"sourceCode":"\t\t//---------------------------------------\n\n\t\t/*\n\t\t  bfd_error_type err = bfd_get_error();\n\t\t  printf(\"bfd_error_msg: %s.\\n\", bfd_errmsg(err));\n\t\t */\n\n\t\t/*if (disassemblerOptions[0] != '\\0'){\n\t\t    DI.disassembler_options = disassemblerOptions;\n\t\t}*/\n\t\tconfigureBfd(bfdfile, arch, mach, endian, &DI, &disassemble_fn);\n\n\t\t/*\n\t\t  err = bfd_get_error();\n\t\t  printf(\"bfd_error_msg: %s.\\n\", bfd_errmsg(err));\n\t\t */\n\n\t\tif (disassemble_fn == NULL){\n\t\t\tfprintf(stderr, \"Error: disassemble_fn is NULL. Nothing I can do.\\n\");\n\t\t\texit(1);\n\t\t}\n\t\telse{\n\t\t\t/*\n\t\t\t  printf(\"the disassemble_fn func pointer is: 0x%08X.\\n\", disassemble_fn);\n\t\t\t  printf(\"We can try to disassemble for this arch/mach. calling disassemble_init_for_target().\\n\");\n\t\t\t */\n\n\t\t\tdisassemble_init_for_target(&DI);\n\t\t\tif (disassemblerOptions[0] != '\\0'){\n\t\t\t\tDI.disassembler_options = disassemblerOptions;\n\t\t\t}\n\n\t\t\t// go diassemble the buffer and build up the result in a accumulator string buffer.\n\t\t\tprocessBuffer(byteBuffer, size >> 1, offset, disassemble_fn, &DI); //\n\n\t\t}\n","sourceCodeStart":436,"sourceCodeEnd":472,"githubUrl":"https://github.com/NationalSecurityAgency/ghidra/blob/d5f144c24d6bc53c9cbf4448c6d11143e7696206/GPL/GnuDisassembler/src/gdis/c/disasm_1.c#L436-L472","documentation":"gdis fatal error: after configureBfd() sets up the disassembler function pointer for the requested arch/mach/endian, disassemble_fn is still NULL, meaning BFD could not locate a disassembler for that combination. The program prints the message and calls exit(1).","triggerScenarios":"Passing an arch/mach pair that BFD does not support with a disassembler, or an endian selection that has no disassembler backend, so disassembler() returns NULL via configureBfd.","commonSituations":"Typo in the arch or mach string; an arch that BFD knows but lacks a disassembler for; a gdis build with a stripped-down BFD that excluded the needed target; version mismatch where a target was removed/renamed.","solutions":["Verify the arch/mach pair against the list printed by the Usage path (run with argc < 8) or bfd_arch_list().","Correct typos in the arch/mach arguments (use canonical BFD names like 'i386:x86-64').","Rebuild gdis against a full BFD configuration that includes the target (./configure --enable-targets=all).","Try the alternate endian ELF path or a different mach for the same arch."],"exampleFix":"// before\n$ gdis \"i386:x86-64\" \"i386\" \"bogus-mach\" 0x400000 a.le a.be 9090\n// configureBfd finds no disassembler -> NULL\n\n// after\n$ gdis \"i386:x86-64\" \"i386\" \"x86-64\" 0x400000 a.le a.be 9090","handlingStrategy":"validation","validationCode":"// confirm BFD can produce a disassembler before relying on it\ndisassembler_ftype fn = disassembler(bfd_get_arch(bfd), bfd_big_endian(bfd), bfd_get_mach(bfd), bfd);\nif (fn == NULL) { fprintf(stderr, \"no disassembler for this arch/mach\\n\"); return 2; }","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Cross-check arch/mach against bfd_arch_list()/Usage output.","Build gdis against a full-targets BFD.","Handle the NULL function pointer instead of calling exit()."],"tags":["disassembler","bfd","configuration","c"],"backgroundTag":null,"analyzedSha":"d5f144c24d6bc53c9cbf4448c6d11143e7696206","analyzedAt":"2026-08-14T01:00:57.564Z","schemaVersion":2},"datasetVersion":"2026-08-14T05:17:29.042Z"}