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Debuginfod - FAQ

What releases of Ubuntu are supported by the service?

debuginfod is currently indexing ddebs packages from all supported Ubuntu releases. Once a release goes unsupported, we stop indexing ddebs from it and eventually stop serving debug symbols for its packages.

How does debuginfod know how to find the debug symbols for the binary I am debugging?

debuginfod relies on a unique hash that identifies binaries and shared libraries called Build-ID. This 160-bit SHA-1 hash is generated by the compiler, and can be consulted using tools like readelf:

$ readelf -n /usr/bin/bash

Displaying notes found in: .note.gnu.property
  Owner                Data size        Description
  GNU                  0x00000020       NT_GNU_PROPERTY_TYPE_0
      Properties: x86 feature: IBT, SHSTK
        x86 ISA needed: x86-64-baseline

Displaying notes found in: .note.gnu.build-id
  Owner                Data size        Description
  GNU                  0x00000014       NT_GNU_BUILD_ID (unique build ID bitstring)
    Build ID: 3e770d2cd0302c6ff2a184e8d2bf4ec98cfcded4

Displaying notes found in: .note.ABI-tag
  Owner                Data size        Description
  GNU                  0x00000010       NT_GNU_ABI_TAG (ABI version tag)
    OS: Linux, ABI: 3.2.0

When you are debugging a program, GDB will send the program’s Build-ID to the debuginfod server, who will check if it has the corresponding debug information for that binary/library. If it does, then it will send the debug symbols over HTTPS back to GDB.

Where does debuginfod store the debug information it downloads?

The debug symbols downloaded from the service are saved inside $XDG_CACHE_HOME/.debuginfod_client/. If $XDG_CACHE_HOME is empty, then ~/.cache/ is used instead.

Can I remove files from the cache directory?

Yes, you can. debuginfod will simply download them again if and when needed.

Can ddebs packages co-exist with debuginfod?

Yes. GDB will try to use local debug information if available. That means that if you have a ddeb package installed that provides the necessary debug symbols for the program being debugged (or if you have already downloaded that information from the debuginfod service earlier), then GDB will use it in favour of performing the download.

Can I use debuginfod with my own binary that links against system libraries?

Yes! debuginfod will obviously not be able to provide any debug symbols for your own program, but it will happily serve debug information for any system libraries that your program links against.

Last updated 11 days ago. Help improve this document in the forum.