GPF on 0xdead000000000100 in nvme_map_data - Linux 5.9.9

[Jürgen Groß]

Marek,

On 06.12.20 17:47, Jason Andryuk wrote:
> On Sat, Dec 5, 2020 at 3:29 AM Roger Pau Monné <roger.pau at citrix.com> wrote:
>>
>> On Fri, Dec 04, 2020 at 01:20:54PM +0100, Marek Marczykowski-Górecki wrote:
>>> On Fri, Dec 04, 2020 at 01:08:03PM +0100, Christoph Hellwig wrote:
>>>> On Fri, Dec 04, 2020 at 12:08:47PM +0100, Marek Marczykowski-Górecki wrote:
>>>>> culprit:
>>>>>
>>>>> commit 9e2369c06c8a181478039258a4598c1ddd2cadfa
>>>>> Author: Roger Pau Monne <roger.pau at citrix.com>
>>>>> Date:   Tue Sep 1 10:33:26 2020 +0200
>>>>>
>>>>>      xen: add helpers to allocate unpopulated memory
>>>>>
>>>>> I'm adding relevant people and xen-devel to the thread.
>>>>> For completeness, here is the original crash message:
>>>>
>>>> That commit definitively adds a new ZONE_DEVICE user, so it does look
>>>> related.  But you are not running on Xen, are you?
>>>
>>> I am. It is Xen dom0.
>>
>> I'm afraid I'm on leave and won't be able to look into this until the
>> beginning of January. I would guess it's some kind of bad
>> interaction between blkback and NVMe drivers both using ZONE_DEVICE?
>>
>> Maybe the best is to revert this change and I will look into it when
>> I get back, unless someone is willing to debug this further.
> 
> Looking at commit 9e2369c06c8a and xen-blkback put_free_pages() , they
> both use page->lru which is part of the anonymous union shared with
> *pgmap.  That matches Marek's suspicion that the ZONE_DEVICE memory is
> being used as ZONE_NORMAL.
> 
> memmap_init_zone_device() says:
> * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
> * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
> * ever freed or placed on a driver-private list.

Second try, now even tested to work on a test system (without NVMe).

Juergen
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-xen-add-helpers-for-caching-grant-mapping-pages.patch
Type: text/x-patch
Size: 15906 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-nvme/attachments/20201207/2eb7e3f0/attachment-0003.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0002-xen-don-t-use-page-lru-for-ZONE_DEVICE-memory.patch
Type: text/x-patch
Size: 6110 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-nvme/attachments/20201207/2eb7e3f0/attachment-0004.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_0xB0DE9DD628BF132F.asc
Type: application/pgp-keys
Size: 3091 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-nvme/attachments/20201207/2eb7e3f0/attachment-0005.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 495 bytes
Desc: OpenPGP digital signature
URL: <http://lists.infradead.org/pipermail/linux-nvme/attachments/20201207/2eb7e3f0/attachment-0001.sig>