On (03/21/16 17:07), Byungchul Park wrote:
[..]
> > > > > It will not print the "lockup suspected" message at all, for e.g.
> > > > > rq->lock,
> > > > > p->pi_lock and any locks which are used within wake_up_process().
> > > >
> > > > this will switch to old SYNC printk() mode should such a lockup ever
> > > > happen, which is a giant advantage over any other implementation; doing
> > > > wake_up_process() within the 'we can detect recursive printk() here'
> > > > gives us better control.
> > > >
> > > > why
> > > >
> > > > printk()->IRQ->wake_up_process()->spin_dump()->printk()->IRQ->wake_up_process()->spin_dump()->printk()->IRQ...
> > > > is better?
> > >
> > > What is IRQ?
> >
> > this is how printk() can print the messages in async mode apart from
> > direct and wake_up_process() in vprintk_emit().
>
> Do you mean IRQ work?
yes.
> Is there any reason why you don't put the wake_up_process() out of the
> critical section
I provided reasons already.
> with my suggestion, even though it can solve the infinite recuresion you
> worried about?
which is 'a static lock pointer in spin_dump()'? I don't think
this will fix recursive printks.
/* seems that for some reason my previous reply was not delivered. re-sending.
*/
-ss
