[PATCH] [47/50] i386: avoid temporarily inconsistent pte-s

[Andi Kleen]

From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
One more of these issues (which were considered fixed a few releases
back): Other than on x86-64, i386 allows set_fixmap() to replace
already present mappings. Consequently, on PAE, care must be taken to
not update the high half of a pte while the low half is still holding
the old value.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>

 arch/i386/mm/pgtable.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: linux/arch/i386/mm/pgtable.c
===================================================================
--- linux.orig/arch/i386/mm/pgtable.c
+++ linux/arch/i386/mm/pgtable.c
@@ -97,8 +97,7 @@ static void set_pte_pfn(unsigned long va
 	}
 	pte = pte_offset_kernel(pmd, vaddr);
 	if (pgprot_val(flags))
-		/* <pfn,flags> stored as-is, to permit clearing entries */
-		set_pte(pte, pfn_pte(pfn, flags));
+		set_pte_present(&init_mm, vaddr, pte, pfn_pte(pfn, flags));
 	else
 		pte_clear(&init_mm, vaddr, pte);
 
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