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From: "Kani, Toshimitsu" <toshi.kani-ZPxbGqLxI0U@public.gmane.org>
To: "akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org"
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: "ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org"
	<ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	"linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org"
	<linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org>,
	"Mulumudi,
	Abhilash Kumar" <m.abhilash-kumar-ZPxbGqLxI0U@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"brian.starkey-5wv7dgnIgG8@public.gmane.org"
	<brian.starkey-5wv7dgnIgG8@public.gmane.org>
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-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.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
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID (diff)
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

  parent reply	other threads:[~2016-08-23 21:25 UTC|newest]

Thread overview: 34+ 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 18:43 ` Toshi Kani
     [not found] ` <1471977800-12688-1-git-send-email-toshi.kani-ZPxbGqLxI0U@public.gmane.org>
2016-08-23 20:42   ` Andrew Morton
2016-08-23 20:42     ` Andrew Morton
     [not found]     ` <20160823134216.8f8e8944581fe1ae202377d1-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2016-08-23 21:25       ` Kani, Toshimitsu [this message]
2016-08-23 21:25         ` Kani, Toshimitsu
2016-08-23 22:32 ` Dan Williams
2016-08-23 22:32   ` Dan Williams
2016-08-23 23:47   ` Kani, Toshimitsu
2016-08-23 23:47     ` Kani, Toshimitsu
2016-08-24  0:34     ` Dan Williams
2016-08-24  0:34       ` Dan Williams
2016-08-24  1:29       ` Kani, Toshimitsu
2016-08-24  1:29         ` Kani, Toshimitsu
2016-08-24  2:53         ` Dan Williams
2016-08-24  2:53           ` Dan Williams
2016-08-24  3:58           ` Dan Williams
2016-08-24  3:58             ` Dan Williams
2016-08-24  4:28             ` Kani, Toshimitsu
2016-08-24  4:28               ` Kani, Toshimitsu
2016-08-24  4:48               ` Dan Williams
2016-08-24  4:48                 ` Dan Williams
2016-08-24 14:40                 ` Kani, Toshimitsu
2016-08-24 14:40                   ` Kani, Toshimitsu
2016-08-24 14:55                   ` Dan Williams
2016-08-24 14:55                     ` Dan Williams
2016-08-24  5:48             ` Dan Williams
2016-08-24  5:48               ` Dan Williams
2016-08-24 15:21               ` Kani, Toshimitsu
2016-08-24 15:21                 ` Kani, Toshimitsu
2016-08-24  1:00     ` Dan Williams
2016-08-24  1:00       ` Dan Williams
2016-08-24  1:38       ` Kani, Toshimitsu
2016-08-24  1:38         ` Kani, Toshimitsu

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