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

Anshuman Khandual
2020-04-29T03:28:39Z

On 04/28/2020 02:51 PM, Catalin Marinas wrote:
> On Tue, Apr 28, 2020 at 04:41:11AM -0400, Qian Cai wrote:
>> On Apr 28, 2020, at 1:54 AM, Anshuman Khandual <Anshuman.Khandual@arm.com> wrote:
>>> That is true. There is a slight change in the rules, making it explicit yes
>>> only when both ARCH_HAS_DEBUG_VM_PGTABLE and DEBUG_VM are enabled.
>>>
>>> +config DEBUG_VM_PGTABLE
>>> + bool "Debug arch page table for semantics compliance"
>>> + depends on MMU
>>> + depends on !IA64 && !ARM
>>> + depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT
>>> + default y if ARCH_HAS_DEBUG_VM_PGTABLE && DEBUG_VM
>>> + help
>>>
>>> The default is really irrelevant as the config option can be set explicitly.
>>
>> That could also explain. Since not long time ago, it was only “default
>> y if DEBUG_VM”, that caused the robot saved a .config with
>> DEBUG_VM_PGTABLE=y by default.
>>
>> Even though you changed the rule recently, it has no effect as the
>> robot could “make oldconfig” from the saved config for each linux-next
>> tree execution and the breakage will go on.
>
> I'm not entirely sure that's the case. This report still points at the
> old commit fa6726c1e7 which has:
>
> + depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT
> + default n if !ARCH_HAS_DEBUG_VM_PGTABLE
> + default y if DEBUG_VM
>
> In -next we now have commit 647d9a0de34c and subsequently modified by
> commit 0a8646638865. So hopefully with the latest -next tree we won't
> see this report.

Could some one from LKP test framework, please confirm if this still causes
above problem on the latest linux-next by default ?