Re: [PATCH 1/11] Add generic helpers for arch IPI function calls

[Mark Lord]

Jens,

While you're in there, :)

Could you perhaps fix this bug (below) if it still exists?

> Date:	Thu, 15 Nov 2007 12:07:48 -0500
> From: Mark Lord <lkml@xxxxxx>
> To: Greg KH <gregkh@xxxxxxx>
> Cc: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>,
> 	Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>,
> 	Alexey Dobriyan <adobriyan@xxxxx>, linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: EIP is at device_shutdown+0x32/0x60
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Content-Transfer-Encoding: 7bit
> Sender: linux-kernel-owner@xxxxxxxxxxxxxxx
>
> ... < snip > ...
>
> Greg, I don't know if this is relevant or not,
> but x86 has bugs in the halt/reboot code for SMP.
>
> Specifically, in native_smp_send_stop() the code now uses
> spin_trylock() to "lock" the shared call buffers,
> but then ignores the result.
>
> This means that multiple CPUs can/will clobber each other
> in that code.
>
> The second bug, is that this code does not wait for the
> target CPUs to actually stop before it continues.
>
> This was the real cause of the failure-to-poweroff problems
> I was having with 2.6.23, which we fixed by using CPU hotplug
> to disable_nonboot_cpus() before the above code ever got run.
>
> Maybe it's related, maybe not.
--
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/