From: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"Mulumudi, Abhilash Kumar" <m.abhilash-kumar@hpe.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"ard.biesheuvel@linaro.org" <ard.biesheuvel@linaro.org>,
"linux-nvdimm@ml01.01.org" <linux-nvdimm@ml01.01.org>,
"brian.starkey@arm.com" <brian.starkey@arm.com>
Subject: Re: [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page()
Date: Tue, 23 Aug 2016 21:25:09 +0000 [thread overview]
Message-ID: <1471987482.32015.111.camel@hpe.com> (raw)
In-Reply-To: <20160823134216.8f8e8944581fe1ae202377d1@linux-foundation.org>
On Tue, 2016-08-23 at 13:42 -0700, Andrew Morton wrote:
> On Tue, 23 Aug 2016 12:43:20 -0600 Toshi Kani <toshi.kani@hpe.com>
> wrote:
>
> >
> > The following BUG was observed while starting up KVM with nvdimm
> > device as memory-backend-file to /dev/dax.
> >
> > BUG: unable to handle kernel NULL pointer dereference at
> > 0000000000000008
> >
> > ...
> >
> > devm_memremap_pages() calls for_each_device_pfn() to walk through
> > all pfns in page_map. pfn_first(), however, returns a wrong pfn
> > that leaves page->pgmap uninitialized.
> >
> > Since arch_add_memory() has set up direct mappings to the NVDIMM
> > range with altmap, pfn_first() should not modify the start pfn.
> > Change pfn_first() to simply return pfn of res->start.
>
> Which kernel version(s) do you think need fixing?
The fix applies to v4.5 and newer versions.
Thanks,
-Toshi
next prev parent reply other threads:[~2016-08-24 2:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 18:43 [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page() Toshi Kani
2016-08-23 20:42 ` Andrew Morton
2016-08-23 21:25 ` Kani, Toshimitsu [this message]
2016-08-23 22:32 ` Dan Williams
2016-08-23 23:47 ` Kani, Toshimitsu
2016-08-24 0:34 ` Dan Williams
2016-08-24 1:29 ` Kani, Toshimitsu
2016-08-24 2:53 ` Dan Williams
2016-08-24 3:58 ` Dan Williams
2016-08-24 4:28 ` Kani, Toshimitsu
2016-08-24 4:48 ` Dan Williams
2016-08-24 14:40 ` Kani, Toshimitsu
2016-08-24 14:55 ` Dan Williams
2016-08-24 5:48 ` Dan Williams
2016-08-24 15:21 ` Kani, Toshimitsu
2016-08-24 1:00 ` Dan Williams
2016-08-24 1:38 ` Kani, Toshimitsu
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