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Neovim: GDB debugging

The Neovim configuration includes nvim-dap, nvim-dap-ui, and nvim-nio for native GDB debugging of C, C++, and Rust programs.

Requirements

  • Neovim 0.11.7 (the workstation's tested version)
  • GDB 14+ built with Python support (required for its DAP interpreter)
  • A local executable compiled with debug symbols

Check the installed debugger:

gdb --version | head -n 1

On supported Debian-based systems, GDB can usually be installed with sudo apt install gdb. Verify the version; older GDB packages do not provide the DAP interpreter.

Install only the newly declared plugins after updating the configuration (without updating unrelated plugins):

:Lazy install

Restart Neovim after installation.

Run a session

Build a C program without optimizations and with debug symbols:

cc -g -O0 -Wall -Wextra -o demo demo.c
nvim demo.c
  1. Place the cursor on an executable line and press Space db to toggle a breakpoint.
  2. Press Space dc, select Launch executable (GDB), and enter the executable's path (for example, /path/to/project/demo).
  3. When the breakpoint is hit, step through the code and inspect the scopes and call stack in the debug UI.
  4. Press Space dq to terminate.

For C++, build with c++ -g -O0; for Rust, use a debug build and select the executable in target/debug/.

Keys

Keys Action
Space db Toggle breakpoint
Space dc Start or continue a session
Space dn Step over
Space di Step into
Space do Step out
Space dp Pause
Space dq Terminate
Space dr Toggle DAP REPL
Space du Toggle debugger UI
Space de Evaluate expression under cursor or visual selection

The debug UI opens automatically when the session starts and closes when the target exits or the debugger terminates it. All mappings load the debugging plugins only when first used.

A second configuration, Attach to process (GDB), prompts for an executable and then lets you select a running PID. Linux may restrict attaching to unrelated processes.

Scope and limitations

These configurations start local GDB. Opening a remote file through svim / Oil SSH does not turn the debugger into a remote debugger. Use a debugger installed on the target machine or configure gdbserver separately when remote debugging is needed.

GDB here debugs userspace processes (for example, a libbpf loader). It does not step through the eBPF program running inside the Linux kernel. Kernel-side investigation requires separate tools such as bpftool, tracefs, and BPF verifier logs.

If a session fails, check :DapShowLog, gdb --version, your working directory (:pwd), and whether the chosen binary contains debug symbols.