Oleg Nesterov <[EMAIL PROTECTED]> writes:
> On 04/24, Eric W. Biederman wrote:
>>
>> I don't know if this is the problem but it certainly needs to be fixed.
>
> I guess you will re-submit these patches soon. May I suggest you to put
> this
>
>> + spin_lock_irq(&tsk->sighand->siglock);
>> + signal_wake_up(tsk, 1);
>> + spin_unlock_irq(&tsk->sighand->siglock);
>
> and this
>
>> fastcall void recalc_sigpending_tsk(struct task_struct *t)
>> {
>> if (t->signal->group_stop_count > 0 ||
>> - (freezing(t)) ||
>> + (freezing(t)) || __kthread_should_stop(t) ||
>
> into the separate patch?
>
> Perhaps I am too paranoid, and most probably this change is good, but
> still I'm afraid this very subtle change may break things. In that case
> it would be easy to revert that only part (for example for the testing
> purposes).
It makes sense. I doubt we are going to run into issues when
we are killing a thread but we certainly could.
Making it easy to test for that scenario would certainly be
a good idea.
> Consider,
>
> current->flags |= PF_NOFREEZE;
>
> while (!kthread_should_stop()) {
>
> begin_something();
>
> // I am a kernel thread, all signals are ignored.
> // I don't want to contribute to loadavg, so I am
> // waiting for the absoulutely critical event in
> // TASK__INTERRUPTIBLE state.
>
> if (wait_event_interruptible(condition))
> panic("Impossible!");
>
> commit_something();
> }
Of course if it's impossible it is most likely there won't be a check
there so something more subtle will happen.
Eric
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