{"record":{"id":"b7d223a7bfdd8b1b","repo":"NationalSecurityAgency/ghidra","slug":"failed-to-allocate-block-blockname","errorCode":null,"errorMessage":"Failed to allocate block: \" + blockName","messagePattern":"Failed to allocate block: \" \\+ blockName","errorType":"exception","errorClass":"MemoryAccessException","httpStatus":null,"severity":"error","filePath":"Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/analysis/MingwRelocationAnalyzer.java","lineNumber":868,"sourceCode":"\t\tfor (long offset = delta; offset < 0x100000000L; offset += delta) {\n\t\t\tAddress addr = space.getAddress(offset);\n\t\t\tAddressIterator addresses = memory.getAddresses(addr, true);\n\t\t\tif (!addresses.hasNext()) {\n\t\t\t\tstartAddr = addr;\n\t\t\t\tbreak;\n\t\t\t}\n\t\t\tAddress nextAddr = addresses.next();\n\t\t\tif (!nextAddr.getAddressSpace().equals(space) ||\n\t\t\t\tnextAddr.subtract(addr) > extBlockSize) {\n\t\t\t\tstartAddr = addr;\n\t\t\t\tbreak;\n\t\t\t}\n\t\t}\n\t\tif (startAddr != null) {\n\t\t\tmemory.createUninitializedBlock(blockName, startAddr, extBlockSize, false);\n\t\t\treturn startAddr;\n\t\t}\n\t\tthrow new MemoryAccessException(\"Failed to allocate block: \" + blockName);\n\t}\n\n\tprivate boolean relocateV1(Address pdwListPayloadAddr, int entryCount, MessageLog log,\n\t\t\tTaskMonitor monitor) throws CancelledException {\n\n\t\tListing listing = program.getListing();\n\t\tData d = listing.getDefinedDataAt(pdwListPayloadAddr);\n\t\tif (d != null && (d.isArray() || d.isStructure())) {\n\t\t\treturn false; // silent - appears to have been previously processed\n\t\t}\n\n\t\tMemory memory = program.getMemory();\n\t\tDataTypeManager dtm = program.getDataTypeManager();\n\t\tRelocationTable relocationTable = program.getRelocationTable();\n\n\t\tAddress addr = pdwListPayloadAddr;\n\t\tDumbMemBufferImpl buf = new DumbMemBufferImpl(memory, pdwListPayloadAddr);\n","sourceCodeStart":850,"sourceCodeEnd":886,"githubUrl":"https://github.com/NationalSecurityAgency/ghidra/blob/d5f144c24d6bc53c9cbf4448c6d11143e7696206/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/analysis/MingwRelocationAnalyzer.java#L850-L886","documentation":"Thrown as MemoryAccessException from the ext-block allocation helper when startAddr is still null after scanning the address space for a gap large enough to hold the uninitialized block. The loop tried successive offsets looking for a free region of extBlockSize; none was found, so createUninitializedBlock could not be called.","triggerScenarios":"The scan over the address space (offset from delta up to 0x100000000L in steps of delta) never finds a gap where the next address is in a different space or far enough away — i.e. memory is fully populated/fragmented with no room for an extBlockSize uninitialized block.","commonSituations":"Analyzing a large or densely-mapped binary where the relevant address space has no contiguous free region of the required size; an extBlockSize that is unexpectedly large due to mis-parsed relocation metadata; running on a program whose image base leaves little headroom.","solutions":["Reduce the requested extBlockSize or relocate to an address space with more free room.","Free/clear overlapping blocks in the target region before allocating.","Run the analyzer earlier in the pipeline before other analyzers consume the available gaps.","Catch MemoryAccessException and skip ext-block relocation handling for this binary."],"exampleFix":"// before — throws when no gap is found\nAddress start = allocateExtBlock(space, extBlockSize, blockName);\n\n// after — scan a wider range or fall back to overlay space\nAddress start = findGap(space, extBlockSize, 0x100000000L, 0x200000000L);\nif (start == null) {\n    // fall back to an overlay address space\n    AddressSpace overlay = program.getAddressFactory().getAddressSpace(\"overlay\");\n    start = overlay.getAddress(extBlockSize);\n}\nif (start == null) {\n    throw new MemoryAccessException(\"Failed to allocate block: \" + blockName);\n}","handlingStrategy":"try-catch","validationCode":"// probe for a free gap before attempting allocation\nAddress gap = findGap(space, extBlockSize, 0L, 0x100000000L);\nif (gap == null) {\n    // no room — skip ext-block allocation\n}","typeGuard":"boolean hasGap = findGap(space, extBlockSize, 0L, 0x100000000L) != null;","tryCatchPattern":"try {\n    allocateExtBlock(space, extBlockSize, blockName);\n} catch (MemoryAccessException e) {\n    log.appendMsg(\"No room for \" + blockName + \": \" + e.getMessage());\n}","preventionTips":["Run the analyzer before others consume address-space gaps.","Reduce extBlockSize when relocation metadata is mis-parsed as huge.","Clear overlapping blocks in the target region before allocating."],"tags":["ghidra","analysis","mingw","memory","memory-access"],"backgroundTag":null,"analyzedSha":"d5f144c24d6bc53c9cbf4448c6d11143e7696206","analyzedAt":"2026-08-14T01:00:57.564Z","schemaVersion":2},"datasetVersion":"2026-08-14T05:17:29.042Z"}