Hi Greg,
On Mon, Jun 18, 2018 at 8:06 AM Greg Ungerer <g...@linux-m68k.org> wrote:
> Booting a ColdFire m68k core with MMU enabled causes a "bad page state"
> oops since commit 1d40a5ea01d5 ("mm: mark pages in use for page tables"):
>
> BUG: Bad page state in process sh pfn:01ce2
> page:004fefc8 count:0 mapcount:-1024 mapping:00000000 index:0x0
> flags: 0x0()
> raw: 00000000 00000000 00000000 fffffbff 00000000 00000100 00000200 00000000
> raw: 039c4000
> page dumped because: nonzero mapcount
> Modules linked in:
> CPU: 0 PID: 22 Comm: sh Not tainted 4.17.0-07461-g1d40a5ea01d5 #13
>
> Fix by calling pgtable_page_dtor() in our __pte_free_tlb() code path,
> so that the PG_table flag is cleared before we free the pte page.
>
> Signed-off-by: Greg Ungerer <g...@linux-m68k.org>
> CC: Matthew Wilcox <mawil...@microsoft.com>
> ---
> arch/m68k/include/asm/mcf_pgalloc.h | 1 +
> 1 file changed, 1 insertion(+)
>
> Matthew: I came across this thread at https://lkml.org/lkml/2018/6/17/163
> about a similar problem with openrisc. Based on that I came up
> with this fix for m68k/ColdFire. Fixes the issue for me.
>
> diff --git a/arch/m68k/include/asm/mcf_pgalloc.h
> b/arch/m68k/include/asm/mcf_pgalloc.h
> index 8b707c249026..8c441eb57b80 100644
> --- a/arch/m68k/include/asm/mcf_pgalloc.h
> +++ b/arch/m68k/include/asm/mcf_pgalloc.h
> @@ -44,6 +44,7 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned
> long address)
> static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t page,
> unsigned long address)
> {
> + pgtable_page_dtor(page);
> __free_page(page);
> }
Do you need a call to pgtable_page_dtor() in pte_free(), too?
On x86 (and motorola_pgalloc.h and sun3_pgalloc.h FWIW), both functions
call pgtable_page_dtor().
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
