On 07/17/2018 03:15 PM, Hazel Russman wrote:
On Tue, 17 Jul 2018 14:06:09 +0200
Frans de Boer <fr...@fransdb.nl> wrote:
On 07/14/2018 06:56 PM, Hazel Russman wrote:
Gentlemen,
I was given your contact details by Michael Shell, who has been helping me to
troubleshoot this problem via the Linux From Scratch support list.
For some time now I have been unable to boot recent kernels (4.14 or later) on my rather
elderly desktop machine. The kernel panics during boot and the problem seems
(superficially) to lie in the acpi driver. At least that is where the visible error
messages come from. Booting with "acpi=off" works but is hardly an ideal
solution.
However a git bisection showed that this is actually a memory management issue.
The kernel commit that caused the problem is :
[33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove
phys_to_virt() usage in ioremap().
Reintroducing the code:
"if (is_ISA_range(phys_addr, last_addr))
return (__force void __iomem *)phys_to_virt(phys_addr);"
makes the system bootable again. I have also tested this on a 4.15 kernel and
it works there too.
If you want me to carry out any further tests, I would be happy to oblige, but
do please bear in mind that I am not an expert, so you will need to give fairly
basic instructions.
Hazel Russman
Hazel, sorry but where should I remove phys_to_virt()? If I delete the
complete if statement in the iounmap function, and replace that with the
above code, i get compile errors.
btw: acpi=off does not solve the issue too.
Frans.
--
No, it's the other way around. phys_to_virt() doesn't get removed; it gets
inserted/reinserted just above the warning not to let normal RAM be remapped.
This is code that was in the kernel before but someone took it out and that was
what was causing me all that trouble.
Here's the patch that I made:
--- linux-4.13.0-rc1/arch/x86/mm/ioremap.c 2018-07-14 13:27:21.000000000 +0100
+++ linux-4.13.0-rc1.new/arch/x86/mm/ioremap.c 2018-07-14 16:00:14.071456762
+0100
@@ -103,7 +103,12 @@
(unsigned long long)phys_addr);
WARN_ON_ONCE(1);
return NULL;
- }
+ }
+/* Don't remap the low PCI/ISA area, it's always mapped..
+ */
+ if (is_ISA_range(phys_addr, last_addr))
+ return (__force void __iomem *)phys_to_virt(phys_addr);
+
/*
* Don't allow anybody to remap normal RAM that we're using..
Sorry if this is a bit inexpert. I'm not used to creating patches and I did the
actual edit by hand.
I didn't touch anything else in that file. And it built normally with just that
edit.
Hello Hazel,
What you inserted is already available as from the 4.13.0 release. But I
can't compile 4.13. anymore because I now have gcc 8.1 instead of the
former 7 series.
I continue my search and go for 4.14 where the check is removed. But i
guess that will fail too and this is no solution to my problem with
systemd freezing just after it found out that it is on a VM.
--- Frans
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