Re: 4.19.5 and later has tons of false messages "BUG: non-zero pgtables_bytes on freeing mm: -16384"

Sasha Levin
2018-12-27T22:52:08Z

On Thu, Dec 27, 2018 at 10:06:09PM +0100, Christian Borntraeger wrote:
>
>
>On 12/27/2018 10:01 PM, Sasha Levin wrote:
>> On Thu, Dec 27, 2018 at 10:28:56AM +0100, Christian Borntraeger wrote:
>>>
>>>
>>> On 27.12.2018 10:13, Christian Borntraeger wrote:
>>>> Martin,
>>>>
>>>> Right now you get a message
>>>> "BUG: non-zero pgtables_bytes on freeing mm: -16384"
>>>> for EVERY process that exits in 4.19.5 and later.
>>>>
>>>> bisect points to
>>>> commit 4136161d676a93fc8df6bdb80d720c15522d6c24
>>>> Author: Martin Schwidefsky <schwidefsky@de.ibm.com>
>>>> Date:   Mon Oct 15 11:09:16 2018 +0200
>>>>
>>>>     s390/mm: fix mis-accounting of pgtable_bytes
>>>>
>>>>     [ Upstream commit e12e4044aede97974f2222eb7f0ed726a5179a32 ]
>>>>
>>>> Turns out that this patch requires several dependencies so the autoselection of this
>>>> patch was missing that.
>>>>
>>>> Can we either revert this patch or add the dependencies?
>>>>
>>>> Christian
>>>>
>>>
>>> It seems that adding
>>>
>>> commit 6d212db11947ae5464e4717536ed9faf61c01e86 ("mm: add mm_pxd_folded checks to pgtable_bytes accounting functions")
>>> fixes the issue.
>>
>> I've queued 6d212db11947 for 4.19 for now, thank you.
>
>Not sure, but you might need
>1071fc5779d98 mm: introduce mm_[p4d|pud|pmd]_folded
>a8874e7e8a889 mm: make the __PAGETABLE_PxD_FOLDED defines non-empty
>
>to avoid compile errors on !s390.

Queued those for 4.19 as well, build looks clean.

--
Thanks,
Sasha