Re: 4.0-rc1/PARISC: BUG: non-zero nr_pmds on freeing mm

["Kirill A. Shutemov" <kirill@shutemov.name>]

On Wed, Feb 25, 2015 at 12:30:48PM -0800, Andrew Morton wrote:
> On Wed, 25 Feb 2015 22:21:30 +0200 "Kirill A. Shutemov" <kirill@shutemov.name> wrote:
> 
> > On Wed, Feb 25, 2015 at 12:54:54AM +0200, Aaro Koskinen wrote:
> > > Hi,
> > > 
> > > Here's a kernel config to reproduce the issue (no special steps needed,
> > > just boot to userspace), and bootlog after that:
> > > 
> > > #
> > > # Automatically generated file; DO NOT EDIT.
> > > # Linux/parisc 4.0.0-rc1 Kernel Configuration
> > ...
> > > [   18.940000] BUG: non-zero nr_pmds on freeing mm: -6
> > 
> > It happens due missing __PAGETABLE_PMD_FOLDED in custom page table
> > folding. This has been fixed in CONFIG_PGTABLE_LEVELS patcheset.
> > 
> > Andrew, are you going to submit that patchset to Linus in this cycle?
> 
> I wasn't planning on doing so - the changelog didn't say anything about
> fixing any regressions.

My bad. Patch 18/19 of the patchset introduced assert which checks that
folded macros are not missed and fixed all cases which trigger it.

> > If not, I can prepare a patchset which only adds missing
> > __PAGETABLE_PUD_FOLDED and __PAGETABLE_PMD_FOLDED.
> 
> Something simple would be preferred, but I don't know how much simpler
> the above would be?

Not much simplier: __PAGETABLE_PMD_FOLDED is missing in frv, m32r, m68k,
mn10300, parisc and s390.

-- 
 Kirill A. Shutemov

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