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From: Dan Williams <dan.j.williams@gmail.com>
To: "dave.jiang" <dave.jiang@intel.com>
Cc: linux-nvdimm@lists.01.org,
	ext4 hackers <linux-ext4@vger.kernel.org>,
	Theodore Ts'o <tytso@mit.edu>,
	Matthew Wilcox <mawilcox@microsoft.com>
Subject: Re: Help trying to use /dev/pmem for dax debugging?
Date: Fri, 10 Aug 2018 10:28:24 -0700	[thread overview]
Message-ID: <CAA9_cmdSxy4vw3wQwj_nkWX+s3Z5-z6rkf9H6j-q-SFZyc5URA@mail.gmail.com> (raw)
In-Reply-To: <4222843a-13ea-e88f-ca74-4e3fe53b4105@intel.com>

Fixed here:

https://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git/commit/?h=akpm/mm&id=6a1830efaf3318696479475620414ccb703757a5

Sent from my phone, forgive formatting.

On Fri, Aug 10, 2018, 9:18 AM Dave Jiang <dave.jiang@intel.com> wrote:

>
>
> On 08/09/2018 07:53 PM, Theodore Y. Ts'o wrote:
> > On Tue, Jul 31, 2018 at 01:27:15PM -0700, Dave Jiang wrote:
> >>
> >> On 7/31/2018 12:36 PM, Ross Zwisler wrote:
> >>> On Mon, Jul 30, 2018 at 07:53:12PM -0400, Theodore Y. Ts'o wrote:
> >>>> In newer kernels, it looks like you can't use /dev/pmem0 for DAX
> >>>> unless it's marked as being DAX capable.  This appears to require
> >>>> CONFIG_NVDIMM_PFN.  But when I tried to build a kernel with that
> >>>> configured, I get the following BUG:
> >>>
> >>> You're using the memmap kernel command line parameter to reserve normal
> >>> memory to be treated as normal memory, but you've also got kernel
> address
> >>> randomization turned on in your kernel config:
> >>>
> >>> CONFIG_RANDOMIZE_BASE=y
> >>> CONFIG_RANDOMIZE_MEMORY=y
> >>>
> >>> You need to turn these off for the memmap kernel command line
> parameter, else
> >>> the memory we're using could overlap with addresses used for other
> things.
> >>
> >> I believe this issue was fixed a while back. Although we probably can
> see if
> >> that is the issue or something else.
> >
> > I turned off RANDOMIZE_BASE and RANDOMIZE_MEMORY, but that didn't fix
> > my problem.
> >
> > It turns out the problem was KASAN.  It looks like using memmap to
> > create test /dev/pmemX devices is not compatible with CONFIG_KASAN
> > being enabled.
> >
> > So I have a workaround for now, but it seems this to be a bug in
> > KASAN, or at least an unfortunate interaction between KASAN and
> > NVDIMM_PFN.
>
> Thanks Ted. I have updated the wiki Ross mentioned to reflect that.
>
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>
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      reply	other threads:[~2018-08-10 17:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-30 23:53 Theodore Y. Ts'o
2018-07-31 19:36 ` Ross Zwisler
2018-07-31 20:27   ` Dave Jiang
2018-08-10  2:53     ` Theodore Y. Ts'o
2018-08-10 16:18       ` Dave Jiang
2018-08-10 17:28         ` Dan Williams [this message]

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