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

Christian Borntraeger
2018-12-27T09:28:56Z

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.

Martin, do we need more?

Christian