Re: [Update] Regression in 4.18 - 32-bit PowerPC crashes on boot - bisected to commit 1d40a5ea01d5

[Larry Finger]

On 07/01/2018 11:16 PM, Michael Ellerman wrote:
> Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
> > On Fri, Jun 29, 2018 at 1:42 PM Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote:
> > > I have more information regarding this BUG. Line 700 of page-flags.h is the
> > > macro PAGE_TYPE_OPS(Table, table). For further debugging, I manually expanded
> > > the macro, and found that the bug line is VM_BUG_ON_PAGE(!PageTable(page), page)
> > > in routine __ClearPageTable(), which is called from pgtable_page_dtor() in
> > > include/linux/mm.h. I also added a printk call to PageTable() that logs
> > > page->page_type. The routine was called twice. The first had page_type of
> > > 0xfffffbff, which would have been expected for a . The second call had
> > > 0xffffffff, which led to the BUG.
> >
> > So it looks to me like the tear-down of the page tables first found a
> > page that is indeed a page table, and cleared the page table bit
> > (well, it set it - the bits are reversed).
> ...
> > That said, can some ppc person who knows the 32-bit ppc code and maybe
> > knows what that "interrupt: 700" means talk about that oddity in the
> > trace, please?
>
> I think everyone else answered your questions here, and it should be
> fixed now in your tree.
>
> Larry let me know if you're still seeing a crash with 4.18-rc3.

The problem is fixed in 4.18-rc3. Thanks to all that helped.

Larry