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Support ELF core dump creation on guest crash #417

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Support ELF core dump creation on guest crash #417

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9037073
crashdump: create core dump file when a guest crashes
dblnz Apr 28, 2025
7f464bc
fixup: add constants instead of hardcoded values and add more comments
dblnz May 2, 2025
1b49eed
crashdump: add SandboxMetadata field that store relevant data about t…
dblnz Apr 28, 2025
4b55039
fixup: change default filename to "<unknown>" and aother small updates
dblnz May 2, 2025
4d4b87f
crashdump: add documentation on how to load a guest core dump in a gd…
dblnz Apr 30, 2025
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25 changes: 25 additions & 0 deletions Cargo.lock
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66 changes: 62 additions & 4 deletions docs/debugging-hyperlight.md
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Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,69 @@ Alternatively, this can be enabled when running a test from the command line:
cargo test --package hyperlight-host --test integration_test --features print_debug -- static_stack_allocate --exact --show-output
```

## Dumping the memory configuration, virtual processor register state and memory contents on a crash or unexpected VM Exit

To dump the details of the memory configuration, the virtual processors register state and the contents of the VM memory set the feature `crashdump` and run a debug build. This will result in a dump file being created in the temporary directory. The name and location of the dump file will be printed to the console and logged as an error message.
## Dumping the guest state to an ELF core dump

To dump the state of the vCPU (general purpose registers, registers) to an `ELF` core dump file set the feature `crashdump` and run a debug build. This will result in a dump file being created in the temporary directory.
The name and location of the dump file will be printed to the console and logged as an error message.

After the core dump has been created, to inspect the state of the guest, load the core dump file using `gdb` or `lldb`.
To do this in vscode, the following configuration can be used to add debug configurations:
```vscode
{
"version": "0.2.0",
"inputs": [
{
"id": "core_dump",
"type": "promptString",
"description": "Path to the core dump file",
},
{
"id": "program",
"type": "promptString",
"description": "Path to the program to debug",
}
],
"configurations": [
{
"name": "[GDB] Load core dump file",
"type": "cppdbg",
"request": "launch",
"program": "${input:program}",
"coreDumpPath": "${input:core_dump}",
"cwd": "${workspaceFolder}",
"MIMode": "gdb",
"externalConsole": false,
"miDebuggerPath": "/usr/bin/gdb",
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
},
{
"description": "Set Disassembly Flavor to Intel",
"text": "-gdb-set disassembly-flavor intel",
"ignoreFailures": true
}
]
},
{
"name": "[LLDB] Load core dump file",
"type": "lldb",
"request": "launch",
"stopOnEntry": true,
"processCreateCommands": [],
"targetCreateCommands": [
"target create -c ${input:core_dump} ${input:program}",
],
},
]
}
```
NOTE: The `CodeLldb` debug session does not stop after launching. To see the code, stack frames and registers you need to
press the `pause` button. This is a known issue with the `CodeLldb` extension [#1245](https://github.com/vadimcn/codelldb/issues/1245).
The `cppdbg` extension works as expected and stops at the entry point of the program.

There are no tools at this time to analyze the dump file, but it can be useful for debugging.

## Debugging guests

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1 change: 1 addition & 0 deletions src/hyperlight_host/Cargo.toml
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Expand Up @@ -46,6 +46,7 @@ tempfile = { version = "3.19", optional = true }
serde_yaml = "0.9"
anyhow = "1.0"
metrics = "0.24.2"
elfcore = { git = "https://github.com/dblnz/elfcore.git", branch = "split-linux-impl-from-elfcore" }
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This needs to be change after the elfcore PR is merged


[target.'cfg(windows)'.dependencies]
windows = { version = "0.61", features = [
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