GDB Cheat Sheet

Yayu Wang included in category Linux

2023-01-26 2026-03-10 255 words 2 minutes

Contents

Configuration

Save history

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set history save on

Args

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gdb --args ./d8 --allow-natives-syntax jit.js --single-threaded

Print

history command

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C-r (reverse-i-search)`':

address

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  x/nfu addr

  n: How many units to print (default 1).

  f: Format character (like print)
      o - octal
      x - hexadecimal
      d - decimal
      u - unsigned decimal
      t - binary
      f - floating point
      a - address
      c - char
      s - string
      i - instruction

      u: Unit.
      b: Byte,
      h: Half-word (two bytes)
      w: Word (four bytes)
      g: Giant word (eight bytes))

print hex

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p/x variable

show all functions

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info functions [regexp]

show address info

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info symbol addr

Kernel Debugging

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(gdb) apropos lx
function lx_current -- Return current task
function lx_module -- Find module by name and return the module variable
function lx_per_cpu -- Return per-cpu variable
function lx_task_by_pid -- Find Linux task by PID and return the task_struct variable
function lx_thread_info -- Calculate Linux thread_info from task variable
lx-dmesg -- Print Linux kernel log buffer
lx-lsmod -- List currently loaded modules
lx-symbols -- (Re-)load symbols of Linux kernel and currently loaded modules

Radare2

analysis

Command	Description
aa	analyze all
afl	list functions
s sym.main	seek to function

inspecting

Command	Description
pdb	basic block
pdf	function disassembly
afa	function arguments
afv	function variables
af	analyze function

graph output

Command	Description
agfv	Interactive Ascii Art
agfd	Graphviz dot