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 cwi...@sinenomine.net ________________________________________ From: openafs-info-ad...@openafs.org <openafs-info-ad...@openafs.org> on behalf of Cheyenne Wills <cwi...@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-ad...@openafs.org <openafs-info-ad...@openafs.org> on behalf of Michael Laß <l...@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.filip...@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 > > mvit...@sinenomine.net > > > > > > > > _______________________________________________ > > OpenAFS-info mailing list > > OpenAFS-info@openafs.org > > https://lists.openafs.org/mailman/listinfo/openafs-info > > > > _______________________________________________ > OpenAFS-info mailing list > OpenAFS-info@openafs.org > https://lists.openafs.org/mailman/listinfo/openafs-info _______________________________________________ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info _______________________________________________ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info _______________________________________________ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info