CODEWITHSUNDEEP
assemblyx86gdbelf
Jet Blue
Jet Blue

Reputation: 5281

GDB does not step correctly

Why does GDB not go to the next machine instruction. In the gif below, I set the program counter to point to start (0x100020), which holds the cli instruction. However, when I enter (gdb) stepi, GDB does not go to the next instruction which is (0x100021) mov $0x104000,%esp, but instead jumps to (0x100023).

Regardless of which instruction I start with, GDB does not jump to the next logical instruction, and instead jumps to a seemingly arbitrary location. Why is this?

enter image description here

Upvotes: 1

Views: 273

Answers (1)

Jet Blue
Jet Blue

Reputation: 5281

32-bit ELF support isn't provided by WSL (yet).

See the following StackOverfow question.

Turns out WSL is the problem, my elf file is 32 bit.

EDIT

While the above is true, 32-bit elf debugging through GDB is possible in WSL if you use QEMU. In my case, GDB was behaving as above not because it was a 32-bit (as I was running the elf file through QEMU) but because the code produced by my assembler did not produce debugging information that GDB understood. I was using NASM and the -F dwarf and -g flags were needed to produce said debugging information.

Upvotes: 1

Related Questions