Re: [PATCH] x86/mm/sme: fix the kdump kernel breakage on SME system when CONFIG_IMA_KEXEC=y

Tom Lendacky
2024-08-27T13:57:21Z

On 8/27/24 00:41, Dave Young wrote:
> On Tue, 27 Aug 2024 at 13:28, Baoquan He <bhe@redhat.com> wrote:
>>
>> On 08/26/24 at 09:24am, Tom Lendacky wrote:
>>> On 8/25/24 21:44, Baoquan He wrote:
>>>> Recently, it's reported that kdump kernel is broken during bootup on
>>>> SME system when CONFIG_IMA_KEXEC=y. When debugging, I noticed this
>>>> can be traced back to commit ("b69a2afd5afc x86/kexec: Carry forward
>>>> IMA measurement log on kexec"). Just nobody ever tested it on SME
>>>> system when enabling CONFIG_IMA_KEXEC.
>>>>

>>
>> I talked to Dave, he reminded me that people could mix the passed in
>> parameter 'size' and the local variable 'size' defined inside the while
>> loop, not sure which 'size' you are referring to.
>>
> Baoquan, you are right, but I think I mistakenly read the code in
> memremap_is_setup_data instead of early_memremap_is_setup_data. You

Ditto.

> can check the memremap_is_setup_data, no "size = sizeof (*data)", so
> these two functions could both need fixes.
>
> Otherwise it would be better to change the function internal variable
> name, it could cause confusion even if the actual result is correct.

Yes, the use of size as a local variable while being passed in as a
parameter is very confusing.

Thanks,
Tom

>
> Thanks
> Dave
>