Re: 2.6.10-mm1 hang

[linux-os]

On Wed, 19 Jan 2005, Andrew Morton wrote:

> Badari Pulavarty <pbadari@xxxxxxxxxx> wrote:
> > I was playing with kexec+kdump and ran into this on 2.6.10-mm1.
> >  I have seen similar behaviour on 2.6.10.
> >
> >  I am using a 4-way P-III machine. I have a module which tries
> >  gets same spinlock twice. When I try to "insmod" this module,
> >  my system hangs. All my windows froze, no more new logins,
> >  console froze, doesn't respond to sysrq. I wasn't expecting
> >  a system hang. Why ? Ideas ?
>
> Maybe all the other CPUs are stuck trying to send an IPI to this one?  An
> NMI watchdog trace would tell.
>
> >  #include <linux/init.h>
> >  #include <asm/uaccess.h>
> >  #include <linux/spinlock.h>
> >  spinlock_t mylock = SPIN_LOCK_UNLOCKED;
> >  static int __init panic_init(void)
> >  {
> >          spin_lock_irq(&mylock);
> >          spin_lock_irq(&mylock);
> >         return 1;
> >  }
> -

What would you expect this to do? After the first lock is
obtained, the second MUST fail forever or else the spin-lock
doesn't work. The code, above, just proves that spin-locks
work!


Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
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