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* [PATCH] m68k: fix "bad page state" oops on ColdFire boot
@ 2018-06-18  6:04 Greg Ungerer
  2018-06-18  6:58 ` Geert Uytterhoeven
  0 siblings, 1 reply; 3+ messages in thread
From: Greg Ungerer @ 2018-06-18  6:04 UTC (permalink / raw)
  To: mawilcox, linux-m68k, linux-kernel; +Cc: Greg Ungerer

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 <>
CC: Matthew Wilcox <>
 arch/m68k/include/asm/mcf_pgalloc.h | 1 +
 1 file changed, 1 insertion(+)

Matthew: I came across this thread at
         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);

^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2018-06-18 13:59 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-18  6:04 [PATCH] m68k: fix "bad page state" oops on ColdFire boot Greg Ungerer
2018-06-18  6:58 ` Geert Uytterhoeven
2018-06-18 13:59   ` Greg Ungerer

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