Hi Greg,
On Mon, Jun 18, 2018 at 8:06 AM Greg Ungerer <gerg@xxxxxxxxxxxxxx> 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 <gerg@xxxxxxxxxxxxxx>
CC: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
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 -- geert@xxxxxxxxxxxxxx
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
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