GNU Debugger (GDB)

Basic Commands

• Find start address and end address of a function

info line <Function Name>

• To view the instruction at a specific address.

x/i <Address>

• Print string pointed by a register.

x/s $rdi

• Disassemble a specific range of address.

disass <start address> <end address>

• Display the local variables

info locals

• Run GDB until the end of current function

finish

• Break out of a loop

until

• Get line number from address

info symbol <address>

Watchpoints and Breakpoints

• Stop when foo is modified

gdb> watch foo

• Watch location

gdb> watch -l foo

• Stop when foo is read

gdb> rwatch foo

• Stop when thread 3 modifies foo

gdb> watch foo thread 3

• Stop when foo is > 10

gdb> watch foo if foo > 10

• Enable a break point.

gdb> enable <comma separated break point numbers..>

• Disable break points.

gdb> disable <comma separated break point numbers..>

• List all break points.

gdb> info b

Debugging a multithreaded program

• List all the threads.

gdb> info threads