linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	kernel-team@lge.com, stable@vger.kernel.org
Subject: Re: [PATCH 2/3] zram: do not use copy_page with non-page alinged address
Date: Sat, 15 Apr 2017 00:40:15 +0900	[thread overview]
Message-ID: <20170414154015.GB16910@bgram> (raw)
In-Reply-To: <20170414054105.GC462@jagdpanzerIV.localdomain>

On Fri, Apr 14, 2017 at 02:41:05PM +0900, Sergey Senozhatsky wrote:
> Hello,
> 
> On (04/13/17 09:17), Minchan Kim wrote:
> > The copy_page is optimized memcpy for page-alinged address.
> > If it is used with non-page aligned address, it can corrupt memory which
> > means system corruption. With zram, it can happen with
> > 
> > 1. 64K architecture
> > 2. partial IO
> > 3. slub debug
> > 
> > Partial IO need to allocate a page and zram allocates it via kmalloc.
> > With slub debug, kmalloc(PAGE_SIZE) doesn't return page-size aligned
> > address. And finally, copy_page(mem, cmem) corrupts memory.
> 
> which would be the case for many other copy_page() calls in the kernel.
> right? if so - should the fix be in copy_page() then?

I thought about it but was not sure it's good idea by several reasons
(but don't want to discuss it in this thread).

Anyway, it's stable stuff so I don't want to make the patch bloat.
If you believe it is right direction and valuable, you could be
a volunteer. :)

Thanks.

  reply	other threads:[~2017-04-14 15:40 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-13  0:17 [PATCH 1/3] zram: fix operator precedence to get offset Minchan Kim
2017-04-13  0:17 ` [PATCH 2/3] zram: do not use copy_page with non-page alinged address Minchan Kim
2017-04-14  5:41   ` Sergey Senozhatsky
2017-04-14 15:40     ` Minchan Kim [this message]
2017-04-17  1:48   ` Sergey Senozhatsky
2017-04-13  0:17 ` [PATCH 3/3] zsmalloc: expand class bit Minchan Kim
2017-04-14  5:07 ` [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky
2017-04-14 15:33   ` Minchan Kim
2017-04-17  1:21     ` Sergey Senozhatsky
2017-04-17  1:54       ` Sergey Senozhatsky
2017-04-17  2:14         ` Minchan Kim
2017-04-17 10:50           ` Sergey Senozhatsky
2017-04-17 10:53             ` Sergey Senozhatsky
2017-04-17 23:53             ` Minchan Kim
2017-04-18  1:53               ` Sergey Senozhatsky
2017-04-18  2:47                 ` Minchan Kim
2017-04-17  1:21 ` Sergey Senozhatsky

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=20170414154015.GB16910@bgram \
    --to=minchan@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=kernel-team@lge.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sergey.senozhatsky.work@gmail.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=stable@vger.kernel.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).