public inbox for linuxppc-dev@ozlabs.org 
 help / color / mirror / Atom feed
From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@au1•ibm.com>
Cc: Paul Mackerras <paulus@samba•org>,
	Anton Blanchard <anton@au1•ibm.com>,
	Hugh Dickins <hughd@google•com>,
	linuxppc-dev@lists•ozlabs.org,
	David Gibson <david@gibson•dropbear.id.au>
Subject: Re: 3.10-rc ppc64 corrupts usermem when swapping
Date: Sun, 02 Jun 2013 12:52:56 +0530	[thread overview]
Message-ID: <8738t1c6y7.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <1370038982.3928.147.camel@pasglop>

Benjamin Herrenschmidt <benh@au1•ibm.com> writes:

> On Fri, 2013-05-31 at 14:45 +0530, Aneesh Kumar K.V wrote:
>
>> > The patch you are running on is what I'll send to Linus for 3.10 (+/-
>> > cosmetics). Aneesh second patch is a much larger rework which will be
>> > needed for THP but that will wait for 3.11. I'm happy for you to test it
>> > but I first want to make sure it's solid with the 3.10 fix :-)
>
> BTW. One concern I still have is that Hugh identified the bad commit
> to be:
>
> 7e74c3921ad9610c0b49f28b8fc69f7480505841
> "powerpc: Fix hpte_decode to use the correct decoding for page sizes".
>
> However, you introduce the return on HPTE not found earlier, in
>
> b1022fbd293564de91596b8775340cf41ad5214c
> "powerpc: Decode the pte-lp-encoding bits correctly."
>
> So while I'm still happy with the current band-aid for 3.10 and am
> about to send it to Linus, the above *does* seem to indicate that
> there is also something wrong with the "Fix hpte_decode..." commit,
> which might not actually get the page size right...
>
> Can you investigate ?

7e74c3921ad9610c0b49f28b8fc69f7480505841 
"powerpc: Fix hpte_decode to use the correct decoding for page sizes"
changes should only impact hpte_decode. We don't change the details
of hpte_actual_psize at all in this patch. That means we should see a
difference only with kexec right ?.

Hugh,

Will you be able to double check whether
7e74c3921ad9610c0b49f28b8fc69f7480505841 is the bad commit. The one
before that is what we changed in the patch that fixed your problem.

-aneesh

  reply	other threads:[~2013-06-02  7:23 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-30  5:47 3.10-rc ppc64 corrupts usermem when swapping Hugh Dickins
2013-05-30  7:00 ` Benjamin Herrenschmidt
2013-05-30  8:27   ` Aneesh Kumar K.V
2013-05-30  8:33     ` Benjamin Herrenschmidt
2013-05-30 13:48       ` Hugh Dickins
2013-05-31  5:05         ` Hugh Dickins
2013-05-31  5:31           ` Benjamin Herrenschmidt
2013-05-31 14:45             ` Hugh Dickins
     [not found]             ` <87ppw7mrx7.fsf@linux.vnet.ibm.com>
2013-05-31 22:23               ` Benjamin Herrenschmidt
2013-06-02  7:22                 ` Aneesh Kumar K.V [this message]
2013-06-02 18:19                   ` Hugh Dickins
2013-05-30 16:10     ` Aneesh Kumar K.V

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=8738t1c6y7.fsf@linux.vnet.ibm.com \
    --to=aneesh.kumar@linux$(echo .)vnet.ibm.com \
    --cc=anton@au1$(echo .)ibm.com \
    --cc=benh@au1$(echo .)ibm.com \
    --cc=david@gibson$(echo .)dropbear.id.au \
    --cc=hughd@google$(echo .)com \
    --cc=linuxppc-dev@lists$(echo .)ozlabs.org \
    --cc=paulus@samba$(echo .)org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox