lkml.org 
[lkml]   [2014]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC PATCH] x86, entry: Switch stacks on a paranoid entry from userspace
On Fri, Nov 14, 2014 at 1:56 PM, Luck, Tony <tony.luck@intel.com> wrote:
>>> Right, I can do it in the meantime and we can always experiment more
>>> later. Getting rid of _TIF_MCE_NOTIFY is a good thing already.
>>
>> Yep, it looks pretty simple - not tested yet, it builds though.
>
> It seems pretty solid under test so far.
>
> Can we make it pass the address/flag to mce_notify_process() too? So
> we can get rid of mce_save_info() and mce_find_info().
>
> We'd need to wrap mce_task_work inside a bigger structure with fields
> to have the address and flags - then use "container_of" inside mce_notify_process().
>
> But I think that means we need more than one of these structures ... we may not
> be done with one before a new machine check occurs. So we'd have to make an
> NMI-safe allocator to grab one for use inside do_machine_check()

I think that this is a considerable benefit of my code, aside from the
non-working-ness part. :-/

--Andy

>
> -Tony
>
> General testing note - one thing I did see was that if inject 1000 errors at 0.3s interval from
> my ssh'd login ... the serial console keeps streaming messages for about 40 seconds
> after my test says it is all done. This might be a factor in the other tests I've been
> running against the stack-switching code (especially with extra debug) ... at some
> point __log_buf must get full - what happens then?



--
Andy Lutomirski
AMA Capital Management, LLC


\
 
 \ /
  Last update: 2014-11-14 23:41    [W:0.086 / U:3.828 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site