On 11/30/18 2:26 PM, Kirill A. Shutemov wrote:
On Fri, Nov 30, 2018 at 01:11:56PM +0000, Hans van Kranenburg wrote:
On 11/29/18 4:06 PM, Kirill A. Shutemov wrote:
On Thu, Nov 29, 2018 at 03:00:45PM +0000, Juergen Gross wrote:
On 29/11/2018 15:32, Kirill A. Shutemov wrote:
On Thu, Nov 29, 2018 at 02:24:47PM +0000, Kirill A. Shutemov wrote:
On Thu, Nov 29, 2018 at 01:35:17PM +0000, 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.
Ahh.. Could you test this:
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index a12afff146d1..7dec63ec7aab 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -496,7 +496,7 @@ static inline bool is_hypervisor_range(int idx) * ffff800000000000 - ffff87ffffffffff is reserved for * the hypervisor. */
- return (idx >= pgd_index(__PAGE_OFFSET) - 16) &&
- return (idx >= pgd_index(__PAGE_OFFSET) - 17) && (idx < pgd_index(__PAGE_OFFSET));
#else return false;
Or, better, this:
That makes it boot again!
Any idea why upstream doesn't need it?
Nope.
I'll prepare a proper fix.
Thanks for looking into this.
In the meantime, I applied the "Or, better, this" change, and my dom0 boots again.
FYI, boot log now: (paste 90d valid) https://paste.debian.net/plainh/48940826
I forgot to CC you:
https://lkml.kernel.org/r/20181130121131.g3xvlvixv7mvlr7b@black.fi.intel.com
Please give it a try.
Ah, right, thanks. The xen-devel list is also not in Cc.
I'll slam it on top of my 4.19.5 debian package build and test.
Hans