We can take a peek into the process stack (technically, the stack of main()) in different ways. Here, we show two possibilities:
- Automatically via the gstack(1) utility
- Manually with the GDB debugger
Peek at the usermode stack, first, via gstack(1):
WARNING! Ubuntu users, you might face an issue here. At the time of writing (Ubuntu 18.04), gstack does not seem to be available for Ubuntu (and its alternative, pstack, does not work well either!). Please use the second method (via GDB), as follows.
As a quick example, we look up the stack of bash (the parameter is the PID of the process):
$ gstack 14654#0 0x00007f3539ece7ea in waitpid () from /lib64/libc.so.6#1 0x000056474b4b41d9 in waitchld.isra ()#2 0x000056474b4b595d ...
