Re: [2.6.21.1] soft lockup when removing netconsole module

[Thomas Gleixner <tglx@linutronix.de>]

On Sat, 2007-05-26 at 18:17 +0200, Folkert van Heusden wrote:
> > > Seems to be hrtimers related - CC'ed Thomas.
> > I doubt that. The tick interrupt just finds out, that the machine is
> > stuck in rmmod.
> > > > Also the rmmod hangs and would not exit even with kill -9. It also
> > > > sucks up 100% cpu.
> > Can you please enable CONFIG_PROVE_LOCKING ?
>
> Luckily I already had :-)
> Here is its output:

So there is no output from lockdep, during the rmmod hang ? The rmmod
sucks 100% cpu, so it busy loops at some place. Looking at the stack
trace this seems to be in:


void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,                                                                                                                 
                                       struct delayed_work *dwork)                                                                                                                  
{                                                                                                                                                                                   
        while (!cancel_delayed_work(dwork))                                                                                                                                         
                flush_workqueue(wq);                                                                                                                                                
}

which is not really related to timers :)

	tglx