Re: [mm/debug] fa6726c1e7: kernel_BUG_at_include/linux/mm.h

Christophe Leroy
2020-04-28T05:25:03Z

Le 28/04/2020 à 04:51, Qian Cai a écrit :
>
>
>> On Apr 27, 2020, at 10:35 PM, Anshuman Khandual <Anshuman.Khandual@arm.com> wrote:
>>
>> Letting CONFIG_DEBUG_VM_PGTABLE enabled via CONFIG_EXPERT for unsupported
>> platforms i.e without ARCH_HAS_DEBUG_VM_PGTABLE, was a conscious decision
>> meant to expand it's adaptability and coverage without requiring any code
>> (i.e Kconfig) change. The easier it is to enable the test on unsupported
>> platforms right now, more folks are likely to try it out thus increasing
>> it's probability to get fixed on those platforms. That is a valid enough
>> reason to have CONFIG_EXPERT based enablement method, IMHO. Also even with
>> CONFIG_EXPERT set, CONFIG_DEBUG_VM_PGTABLE does not get enabled by default
>> automatically.
>
> No, I am talking about PAE. There is a distinction between known broken that nobody cares (like arm32) and in-progress/unknown status (like s390).
>
> Also, it is not very nice to introduce regressions for robots when testing PAE because they always select CONFIG__EXPERT and CONFIG_DEBUG_VM.
>

Having CONFIG_EXPERT and CONFIG_DEBUG_VM is not enough to get
CONFIG_DEBUG_VM_PGTABLE set to yes.

By default, CONFIG_DEBUG_VM_PGTABLE is set to no when
ARCH_HAS_DEBUG_VM_PGTABLE is not set.

Christophe