Re: [PATCH RFC] NMI Re-introduce un[set]_nmi_callback

From: aris
Date: Thu Sep 04 2008 - 10:50:41 EST


> Peter -- good question. The HP systems with this HW will use the hpwdt
> driver in place of the default nmi watchdog. When the HW detects a
> problem, the HW will generate a single NMI that the driver will handle.
> The driver doesn't want the NMI to be rejected due to a reason code.
> I'm sure that Thomas Mingarelli, who is cc'd, can provide further
> details.
it's not the first time this is asked. I think it's needed for some kernel
debuggers as well: make sure a function is called before anything else
when a NMI happens. something that the notifier chain can't do.

> From our quick conversation as well, you raised an interesting point
> about oprofile, kgdb, and other subsystems that use the NMI notifier
> chains -- they may be impacted by the NMI callback.
>
> Don (dzickus) or Aris, do you have any thoughts on how to get around the
> second issue? We could check to see if anything is registered on the
> notifier chain and the fail to register the callback.
or call the notifier chain in case it indentifies it's a unexpected NMI?

--
Aristeu

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/