Messages in this thread | | | Date | Fri, 4 Oct 2013 14:33:53 +0100 | From | Andrew Cooper <> | Subject | Re: [Xen-devel] [PATCH] xen: Fix possible user space selector corruption |
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On 04/10/13 14:20, Konrad Rzeszutek Wilk wrote: > On Thu, Oct 03, 2013 at 01:51:32PM +0100, Frediano Ziglio wrote: >> On Thu, 2013-10-03 at 11:04 +0100, Andrew Cooper wrote: >>> On 03/10/13 09:24, Frediano Ziglio wrote: >>>> >>>> Bisecting the code commit 7076aada1040de4ed79a5977dbabdb5e5ea5e249 appears >>>> to be the first one that have this issue. >>>> >>>> Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com> >>> In terms of the correctness of the fix, >>> >>> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> > Should this also go in stable tree?
Very much so. The change which exposed it for us was from 3.7 iirc, but I believe it has been a latent bug for as long as the native early boot code uses __USER_DS.
>>> However, I am not sure the comment is necessary. The prevailing style >>> is for no justification of loads of segment selectors on boot, and the >>> comment itself refers simply to an interaction issue of 32bit on Xen >>> when making use of sysenter. >>> >> Suggestion for the comment ?? >> >> Frediano
My suggestion was to omit the comment entirely, or simplify it to just:
/* Xen starts us with XEN_FLAT_RING1_DS, but linux code expects __USER_DS */
Anyone who wants the full explanation can read the patch description.
~Andrew
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