[OpenAFS] kernel 5.14 RIP with openafs 1.8.8

Mon, 11 Oct 2021 08:53:19 +0200

just to confirm, works fine with the patch.

Andrej

On 10/7/21 8:09 PM, Cheyenne Wills wrote:
> A patch has been submitted for review (https://gerrit.openafs.org/#/c/14826).  The fix itself was simple (2 lines), it just explicitly sets a function for the set_page_dirty operation to what was being used by default in the older Linux kernels.
>
> I was able to consistently reproduce the problem by using the iozone benchmarking tool (iozone -B -a).
>
> Thanks to Andrej Filipcic for reporting the problem, and Michael Laß for finding the offending Linux 5.14 commit
>
> Cheyenne Wills
> cwills@sinenomine.net
> ________________________________________
> From: openafs-info-admin@openafs.org <openafs-info-admin@openafs.org> on behalf of Cheyenne Wills <cwills@sinenomine.net>
> Sent: Wednesday, October 6, 2021 10:19:05 AM
> Cc: OpenAFS
> Subject: Re: [OpenAFS] kernel 5.14 RIP with openafs 1.8.8
>
> I've started to look at a fix for this.
>
> Thanks for the report
> ________________________________________
> From: openafs-info-admin@openafs.org <openafs-info-admin@openafs.org> on behalf of Michael Laß <lass@mail.upb.de>
> Sent: Wednesday, October 6, 2021 2:05 AM
> To: Mark Vitale; Andrej Filipcic
> Cc: OpenAFS
> Subject: Re: [OpenAFS] kernel 5.14 RIP with openafs 1.8.8
>
> OK, I might have found the culprit. OpenZFS users were experiencing the
> same [1] so I looked at what they had to change to support Linux 5.14.
>
> I noticed this change: https://github.com/openzfs/zfs/pull/12427
> It is required due to this upstream change:
> https://github.com/torvalds/linux/commit/0af573780b0b13fceb7fabd49dc1b073cee9a507
>
> In fact, filemap_page_mkwrite, which is on the top of the shown call
> traces, calls set_page_dirty(page). So if that is an invalid function
> pointer, things go wrong.
>
> Best,
> Michael
>
> [1]:
> https://forum.endeavouros.com/t/null-pointer-dereference-with-kernel-5-14-1/17312
>
> Am Mittwoch, dem 06.10.2021 um 09:49 +0200 schrieb Michael Laß:
>> [reposting from correct mail address and with small change]
>>
>> Hi,
>>
>> it looks like people using Arch Linux get this error as well after
>> updating to 5.14 [previously I wrote 5.14.9 but the reporter upgraded
>> from 5.13 so it could be any subversion]. Here is a bug report:
>>
>> https://bugs.archlinux.org/task/72340
>>
>> And here is a direct link to the reporter's crash log:
>> https://bugs.archlinux.org/task/72340?getfile=20754
>>
>> So the error as well is:
>>> Okt 04 09:18:48  kernel: Code: Unable to access opcode bytes at RIP
>>> 0xffffffffffffffd6.
>> The call trace looks is also basically identical:
>>> Okt 04 09:18:48  kernel: Call Trace:
>>> Okt 04 09:18:48  kernel:  filemap_page_mkwrite+0xdf/0x190
>>> Okt 04 09:18:48  kernel:  do_page_mkwrite+0x55/0xb0
>>> Okt 04 09:18:48  kernel:  do_wp_page+0x22b/0x2d0
>>> Okt 04 09:18:48  kernel:  ? cp_new_stat+0x134/0x160
>>> Okt 04 09:18:48  kernel:  __handle_mm_fault+0xd45/0x15c0
>>> Okt 04 09:18:48  kernel:  handle_mm_fault+0xd5/0x2a0
>>> Okt 04 09:18:48  kernel:  do_user_addr_fault+0x1de/0x690
>>> Okt 04 09:18:48  kernel:  exc_page_fault+0x72/0x170
>>> Okt 04 09:18:48  kernel:  ? asm_exc_page_fault+0x8/0x30
>>> Okt 04 09:18:48  kernel:  asm_exc_page_fault+0x1e/0x30
>> Best,
>> Michael
>>
>> Am Montag, dem 04.10.2021 um 14:29 +0000 schrieb Mark Vitale:
>>> Andrej,
>>>
>>>> On Oct 4, 2021, at 5:47 AM, Andrej Filipcic
>>>> <Andrej.Filipcic@ijs.si>
>>>> wrote:
>>>>
>>>> I tried kernel 5.14.9 and openafs 1.8.8. It fails just after login
>>>> with
>>>>
>>>> <snip>
>>>>
>>>> any clues or patches?
>>>>
>>>>
>>> I consulted with a colleague and we haven't seen a failure like
>>> this.
>>> The backtrace doesn't contain any AFS code either, so no clues
>>> there.
>>> Is it possible your OpenAFS kernel module wasn't rebuilt for this
>>> kernel?  (mismatched kernel version)
>>>
>>>
>>> Regards,
>>> --
>>> Mark Vitale
>>> mvitale@sinenomine.net
>>>
>>>
>>>
>>> _______________________________________________
>>> OpenAFS-info mailing list
>>> OpenAFS-info@openafs.org
>>> https://lists.openafs.org/mailman/listinfo/openafs-info
>>
>>
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>
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-- 
_____________________________________________________________
    prof. dr. Andrej Filipcic,   E-mail: Andrej.Filipcic@ijs.si
    Department of Experimental High Energy Physics - F9
    Jozef Stefan Institute, Jamova 39, P.o.Box 3000
    SI-1001 Ljubljana, Slovenia
    Tel.: +386-1-477-3674    Fax: +386-1-477-3166
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