Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang afterPTRACE_ATTACH

[Oleg Nesterov]

On 02/14, Denys Vlasenko wrote:
>
> Basically, we have TASK_RUNNING, TASK_STOPPED and TASK_TRACED
> states, and after entering TASK_TRACED state we lose information
> in which state we were before entering it. We need to remember
> old state and restore it in order for this example to work.

Actually, we do not lose this info. So the kernel can change it
back to TASK_STOPPED after ptrace(PTRACE_CONT), and this is what
PTRACE_CONT-doesnt-resume-until-SIGCONT was supposed to do.

> Or we can avoid entering TASK_TRACED on ptrace(PTRACE_GETSIGINFO) et al.
> Can we remain in TASK_STOPPED?

Oh, unlikely, I think.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/