Re: [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdogand touch_softlockup_watchdog

From: Maxim Levitsky
Date: Thu Aug 26 2010 - 06:14:47 EST


On Thu, 2010-08-19 at 22:57 -0400, Don Zickus wrote:
> On Wed, Aug 18, 2010 at 01:01:56PM -0700, Andrew Morton wrote:
> > The surprise new requirement that touch_nmi_watchdog() be called from
> > non-preemptible code does seem to make sense IMO. It's hard to see why
> > anyone would be touching the watchdog unless he's spinning in irqs-off
> > code. Except, of course, when we have a utility function which can be
> > called from wither irqs-on or irqs-off: acpi_os_stall().
> >
> > That being said, it's not good to introduce new API requirements by
> > accident! An audit of all callers should first be performed, at least.
> >
> >
> > The surprise new requirement that touch_softlockup_watchdog() be called
> > from non-preemptible code doesn't make sense IMO. If I have a piece of
> > code in the kernel which I expect to sit in TASK_UNINTERRUPTIBLE state
> > for three minutes waiting for my egg to boil, I should be able to do
> > that and I should be able to touch the softlockup detector without
> > needing to go non-preemptible.
>
> Ok, so here is my patch that syncs the touch_*_watchdog back in line with
> the old semantics. Hopefully this will undo any harm I caused.

Was this patch forgotten?

Best regards,
Maxim Levitsky

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