From: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "dan.j.williams@intel.com" <dan.j.williams@intel.com>
Cc: "Mulumudi, Abhilash Kumar" <m.abhilash-kumar@hpe.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"ard.biesheuvel@linaro.org" <ard.biesheuvel@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"brian.starkey@arm.com" <brian.starkey@arm.com>
Subject: Re: [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page()
Date: Wed, 24 Aug 2016 14:40:07 +0000 [thread overview]
Message-ID: <1472049570.1532.10.camel@hpe.com> (raw)
In-Reply-To: <CAPcyv4hZEU3bnpiSCr3KFxF+MiGDGzB5NdopWkFB5CWazD1pkw@mail.gmail.com>
On Tue, 2016-08-23 at 21:48 -0700, Dan Williams wrote:
> On Tue, Aug 23, 2016 at 9:28 PM, Kani, Toshimitsu <toshi.kani@hpe.com
> >
> > BTW, why does devm_memremap_pages() put a whole range to
> > pgmap_radix as device memory, but only initialize page->pgmap for
> > its data range? Is there particular reason for this inconsistency?
>
> The radix tree is indexed by section number, but we don't always
> initialize a full section. The cases when we don't use a full
> section is when it overlaps device metadata, or if a platform
> multiplexes the device memory range with another resource within the
> same section.
I see, but I still feel odd about making get_dev_pagemap() to work for
metadata, but get_page() -> get_zone_device_page() to crash like this.
follow_devmap_pmd() assumes get_page() to work when get_dev_pagemap()
returns a valid pgmap...
Thanks,
-Toshi
next prev parent reply other threads:[~2016-08-24 14:40 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
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 [this message]
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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