On 2020-11-02 17:25:14 [+0100], Oleg Nesterov wrote:
> On 11/02, Oleg Nesterov wrote:
> >
> > spin_lock_irq(&task->sighand->siglock);
> > - if (task->state == __TASK_TRACED) {
> > - if (__fatal_signal_pending(task))
> > - wake_up_state(task, __TASK_TRACED);
> > - else
> > - task->state = TASK_TRACED;
> > - }
> > +
> > + raw_spin_lock(&task->pi_lock);
>
> but perhaps it should be raw_spin_lock_irq() ?
>
> I know nothing about kernel-rt, however it seems that spin_lock_irq()
> from include/linux/spinlock_rt.h doesn't disable irqs?
I don't exactly how much breaks when we turn siglock into a
raw_spinlock_t but there is a memory allocation in __send_signal() which
is a no no.
There is task_is_traced() which looks under the PI lock for the task
state to be sure (we a few of those). I haven't looked at the patch yet…
> Oleg.
Sebastian
