Messages in this thread | | | Subject | Re: Linux 5.0 regression: BUG: unable to handle kernel paging request at ffff888023e26778 RIP: e030:move_page_tables+0x7c1/0xae0 | From | Juergen Gross <> | Date | Sat, 9 Feb 2019 19:59:58 +0100 |
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On 09/02/2019 19:51, Sander Eikelenboom wrote: > On 09/02/2019 19:48, Juergen Gross wrote: >> On 09/02/2019 19:45, Sander Eikelenboom wrote: >>> On 09/02/2019 09:26, Sander Eikelenboom wrote: >>>> L.S., >>>> >>>> >>>> While testing a Linux 5.0-rc5-ish kernel (pull of yesterday) with some additional patches for >>>> already reported other issues i came across the issue below which i haven't seen with 4.20.x >>>> >>>> I haven't got a reproducer so i might be hard to hit it again, >>>> system is AMD and this is from the host kernel running under >>>> the Xen hypervisor might it matter. >>> >>>> -- >>>> >>>> Sander >>> >>> Hi Boris / Juergen, >>> >>> The commit causing this is: >>> 2c91bd4a4e2e530582d6fd643ea7b86b27907151 mm: speed up mremap by 20x on large regions >>> >>> Since it seems there haven't been any other reports about this .. >>> could it be this doesn't specifically work well with a Xen PVH dom0 ? >> >> PVH? Not PV? > > Ah sorry, indeed PV !
Okay, found the problem. set_pmd_at() is used in above commit for writing a PMD entry with a page table address. In all other places it is used only for huge pages, which are not possible in PV guests.
I'll send a patch on Monday.
Juergen
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