Re: [Xen-devel] kexec: Clear notes during setup

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 04/05/12 13:51, Jan Beulich wrote:
>>>> On 04.05.12 at 13:42, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>> I know that xen-unstable is on a feature freeze, and this is not
>> strictly a bugfix (yet; see below), but as it is safe and designed to
>> help clarity in the case of a crash, so I request that it be considered
>> for inclusion.
>>
>> I have constructed an artificial case where the information reported in
>> 1 per-cpu crash note was stale by using low_crashinfo mode, crashing
>> Xen, allowing it to reboot, offlining a CPU then re-crashing Xen.  This
>> leaves stale register state written into the offlined CPU crash
>> information.  In this case, the information was stale but correct, due
>> to the predictable nature of the Xen crash path from the 'C' debug key,
>> but there is no guarantee that in the case of a real crash, the same
>> will still be true.
> Apart from the missing blanks in the for() statement (which could as
> well be a simple memset() afaict),
> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> I personally would think that this can go in as a bug fix.
>
> Jan

How would you format the for loop differently? (Not that I mind - just
so I know for next time)

As for clear_page vs memset - clear_page is faster, and liable to be
conditionally tuned more in the future.

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com


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