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From: Andrew Morton <akpm@linux-foundation.org>
To: Toshi Kani <toshi.kani@hpe.com>
Cc: dan.j.williams@intel.com, m.abhilash-kumar@hpe.com,
	linux-nvdimm@ml01.01.org, linux-kernel@vger.kernel.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Brian Starkey <brian.starkey@arm.com>
Subject: Re: [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page()
Date: Tue, 23 Aug 2016 13:42:16 -0700	[thread overview]
Message-ID: <20160823134216.8f8e8944581fe1ae202377d1@linux-foundation.org> (raw)
In-Reply-To: <1471977800-12688-1-git-send-email-toshi.kani@hpe.com>

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?

  reply	other threads:[~2016-08-23 20:42 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-23 18:43 Toshi Kani
2016-08-23 20:42 ` Andrew Morton [this message]
2016-08-23 21:25   ` Kani, Toshimitsu
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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