Devcontainer 内で GDB を使用する

Devcontainer 内で GDB を使用する#

VSCode の Devcontainer 上で GDB を使用すると、普段は出ない警告やエラーが出るケースがある。

例えば、デッドロックや無限ループで止まってしまったプロセスに GDB でアタッチしようとすると…

$ gdb ./build/Debug/bin/hash_tables_bench_maps 1188
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Reading symbols from ./build/Debug/bin/hash_tables_bench_maps...
Attaching to program: /workspaces/cpp-hash-tables/build/Debug/bin/hash_tables_bench_maps, process 1188
Could not attach to process.  If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user.  For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
/workspaces/cpp-hash-tables/1188: No such file or directory.

ptrace の権限がないというエラーが発生する。

このような問題は devcontainer.json に以下の設定を加えることで解決する。

{
  "runArgs": ["--cap-add=SYS_PTRACE", "--security-opt", "seccomp=unconfined"],
}

See also