On 12/6/18 12:31 PM, Juergen Gross wrote: > On 06/12/2018 12:13, Greg KH wrote: >> On Thu, Nov 29, 2018 at 02:35:17PM +0100, Juergen Gross wrote: >>> On 29/11/2018 14:26, Kirill A. Shutemov wrote: >>>> On Thu, Nov 29, 2018 at 09:41:25AM +0000, Juergen Gross wrote: >>>>> On 29/11/2018 02:22, Hans van Kranenburg wrote: >>>>>> Hi, >>>>>> >>>>>> As also seen at: >>>>>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914951 >>>>>> >>>>>> Attached there are two serial console output logs. One is starting with >>>>>> Xen 4.11 (from debian unstable) as dom0, and the other one without Xen. >>>>>> >>>>>> [ 2.085543] BUG: unable to handle kernel paging request at >>>>>> ffff888d9fffc000 >>>>>> [ 2.085610] PGD 200c067 P4D 200c067 PUD 0 >>>>>> [ 2.085674] Oops: 0000 [#1] SMP NOPTI >>>>>> [ 2.085736] CPU: 1 PID: 1 Comm: swapper/0 Not tainted >>>>>> 4.19.0-trunk-amd64 #1 Debian 4.19.5-1~exp1+pvh1 >>>>>> [ 2.085823] Hardware name: HP ProLiant DL360 G7, BIOS P68 05/21/2018 >>>>>> [ 2.085895] RIP: e030:ptdump_walk_pgd_level_core+0x1fd/0x490 >>>>>> [...] >>>>> >>>>> The offending stable commit is 4074ca7d8a1832921c865d250bbd08f3441b3657 >>>>> ("x86/mm: Move LDT remap out of KASLR region on 5-level paging"), this >>>>> is commit d52888aa2753e3063a9d3a0c9f72f94aa9809c15 upstream. >>>>> >>>>> Current upstream kernel is booting fine under Xen, so in general the >>>>> patch should be fine. Using an upstream kernel built from above commit >>>>> (with the then needed Xen fixup patch 1457d8cf7664f34c4ba534) is fine, >>>>> too. >>>>> >>>>> Kirill, are you aware of any prerequisite patch from 4.20 which could be >>>>> missing in 4.19.5? >>>> >>>> I'm not. >>>> >>>> Let me look into this. >>>> >>> >>> What is making me suspicious is the failure happening just after >>> releasing the init memory. Maybe there is an access to .init.data >>> segment or similar? The native kernel booting could be related to the >>> usage of 2M mappings not being available in a PV-domain. >> >> Did this ever get fixed anywhere that I can properly backport it to the >> 4.19.y tree? > > https://lore.kernel.org/lkml/20181130202328.65359-2-kirill.shutemov@xxxxxxxxxxxxxxx/ > > Still pending upstream. Just pinged tglx. And FYI, I actually use this patch on top of 4.19.5 now. It just applies and works. Hans
