Re: [PATCH] PM: hibernate: Fix level3 translation fault in swsusp_save()

[Yaxiong Tian <13327272236@163.com>]

在 2024/2/29 17:42, Mike Rapoport 写道:
> On Tue, Feb 27, 2024 at 03:51:25PM +0800, Yaxiong Tian wrote:
>> 在 2024/2/26 17:14, Mike Rapoport 写道:
>>> On Mon, Feb 26, 2024 at 09:37:06AM +0100, David Hildenbrand wrote:
>>>> On 26.02.24 04:42, Yaxiong Tian wrote:
>>>>> From: Yaxiong Tian <tianyaxiong@kylinos.cn>
>>>>>
>>>>> On ARM64 machines using UEFI, if the linear map is not set (can_set_direct_map()
>>>>> return false), swsusp_save() will fail due to can't finding the map table
>>>>> under the nomap memory.such as:
>>> can_set_direct_map() has nothing to do with presence or absence of the
>>> linear map.
>>>
>>> Do you mean that kernel_page_present() presumes that a page is present when
>>> can_set_direct_map() returns false even for NOMAP ranges?
>> Yes， in swsusp_save()->copy_data_pages()->page_is_saveable(),
>> kernel_page_present() presumes that a page is present when
>> can_set_direct_map()
>> returns false even for NOMAP ranges.So NOMAP pages will saved in after,and
>> then
>> cause level3 translation fault in this pages.
> So this should be the description of the problem in the changelog rather
> than saying "if the linear map is not set (can_set_direct_map() return
> false)"
>
>>>>> QEMU ARM64 using UEFI also has the problem by setting can_set_direct_map()
>>>>> return false.
>>> Huh?
>>> Why would you do that?
>>>
>> I discovered this problem when upgrading from 5.4 to 6.6 using the 5.4
>> configuration.
>> So I using latest linux-next code,find the problem still exist.To rule out
>> the effects
>> of a particular machine，I also use qemu to check it.
> I believe this can be reproduced if you boot with rodata=off and then
> a better description would be something like
>
> 	This issue can be reproduced in QEMU when booting with rodata=off

Thanks, I opt commit messages,and move !pfn_is_map_memory() check from 
page_is_saveable()
to arm64::pfn_is_nosave().  The patch v2 is in:

https://lore.kernel.org/all/20240301021924.33210-1-13327272236@163.com/

I heard that if it is a single PATCH it should be placed under the 
original mailing list,
so please ignore the February 27 patch mailing.

>