From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Stefan Bader <stefan.bader@canonical.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: Is: [PATCH] x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode. Was: Re: [PATCH] x86/paravirt: Partially revert "remove lazy mode in interrupts"
Date: Mon, 3 Oct 2011 13:04:01 -0400 [thread overview]
Message-ID: <20111003170401.GD4420@phenom.oracle.com> (raw)
In-Reply-To: <4E859312.40309@canonical.com>
On Fri, Sep 30, 2011 at 11:59:46AM +0200, Stefan Bader wrote:
> On 26.09.2011 21:34, Konrad Rzeszutek Wilk wrote:
> > On Mon, Sep 26, 2011 at 09:22:21AM -0700, Jeremy Fitzhardinge wrote:
> >> On 09/26/2011 06:13 AM, Konrad Rzeszutek Wilk wrote:
> >>> which has git commit b8bcfe997e46150fedcc3f5b26b846400122fdd9.
> >>>
> >>> The unintended consequence of removing the flushing of MMU
> >>> updates when doing kmap_atomic (or kunmap_atomic) is that we can
> >>> hit a dereference bug when processing a "fork()" under a heavy loaded
> >>> machine. Specifically we can hit:
> >>
> >> The patch is all OK, but I wouldn't have headlined it as a "partial
> >> revert" - the important point is that the pte updates in k(un)map_atomic
> >> need to be synchronous, regardless of whether we're in lazy_mmu mode.
> >>
> >> The fact that b8bcfe997e4 introduced the problem is interesting to note,
> >> but only somewhat relevant to the analysis of what's being fixed here.
> >
> > Good point. How about
> >
>
> Limiting the cc's for just asking about status...
Ah, got this email:
The patch titled
Subject: x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode
has been added to the -mm tree. Its filename is
x86-paravirt-pte-updates-in-kunmap_atomic-need-to-be-synchronous-regardless-of-lazy_mmu-mode.patch
so it is definitly on the train.
next prev parent reply other threads:[~2011-10-03 17:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-26 13:13 [PATCH] x86/paravirt: Partially revert "remove lazy mode in interrupts" Konrad Rzeszutek Wilk
2011-09-26 13:13 ` Konrad Rzeszutek Wilk
2011-09-26 16:22 ` Jeremy Fitzhardinge
2011-09-26 19:34 ` Is: [PATCH] x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode. Was: " Konrad Rzeszutek Wilk
2011-09-26 19:34 ` Konrad Rzeszutek Wilk
2011-09-30 9:59 ` Stefan Bader
2011-10-03 16:50 ` Konrad Rzeszutek Wilk
2011-10-03 17:04 ` Konrad Rzeszutek Wilk [this message]
2011-10-25 17:55 ` Christopher S. Aker
2011-10-25 18:19 ` Konrad Rzeszutek Wilk
2011-10-25 18:26 ` Konrad Rzeszutek Wilk
2011-09-30 14:22 ` Konrad Rzeszutek Wilk
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20111003170401.GD4420@phenom.oracle.com \
--to=konrad.wilk@oracle.com \
--cc=stefan.bader@canonical.com \
--cc=xen-devel@lists.xensource.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.