why is the Operation not permitted?

[Denys Vlasenko]

On 03/31/2012 05:54 PM, Guy wrote:
>   Hello!
>
>   This might be a trivial question:
>   I am debbuging my_program with gdb such as:
>   gdb my_program
>   GNU gdb (GDB) 7.4
>   ...
>   Reading symbols from my_program
>   (gdb) run
>   ...
>
>   And now I want to see what is happening:
>   strace -p<pid of my_program>
>
>   and get an error:
>   attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted
>
>   Why this?

Because ptrace API was badly designed from the start.
Among other deficiencies, it does not allow multiple
tracers.

-- 
vda