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    SubjectRe: [PATCH v2 07/12] ptrace: Don't change __state
    On 04/29, Eric W. Biederman wrote:
    >
    > Stop playing with tsk->__state to remove TASK_WAKEKILL while a ptrace
    > command is executing.

    Eric, I'll read this patch and the rest of this series tomorrow.
    Somehow I failed to force myself to read yet another version after
    weekend ;)

    plus I don't really understand this one...

    > #define TASK_KILLABLE (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
    > #define TASK_STOPPED (TASK_WAKEKILL | __TASK_STOPPED)
    > -#define TASK_TRACED (TASK_WAKEKILL | __TASK_TRACED)
    > +#define TASK_TRACED __TASK_TRACED
    ...
    > static inline void signal_wake_up(struct task_struct *t, bool resume)
    > {
    > - signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
    > + unsigned int state = 0;
    > + if (resume) {
    > + state = TASK_WAKEKILL;
    > + if (!(t->jobctl & JOBCTL_PTRACE_FROZEN))
    > + state |= __TASK_TRACED;
    > + }
    > + signal_wake_up_state(t, state);

    Can't understand why is this better than the previous version which removed
    TASK_WAKEKILL if resume... Looks a bit strange to me. But again, I didn't
    look at the next patches yet.

    > @@ -2209,11 +2209,8 @@ static int ptrace_stop(int exit_code, int why, int clear_code,
    > spin_lock_irq(&current->sighand->siglock);
    > }
    >
    > - /*
    > - * schedule() will not sleep if there is a pending signal that
    > - * can awaken the task.
    > - */
    > - set_special_state(TASK_TRACED);
    > + if (!__fatal_signal_pending(current))
    > + set_special_state(TASK_TRACED);

    This is where I stuck. This probably makes sense, but what does it buy
    for this particular patch?

    And if we check __fatal_signal_pending(), why can't ptrace_stop() simply
    return ?

    Oleg.

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