[patch 18/29] i386: avoid temporarily inconsistent pte-s

[Greg Kroah-Hartman <gregkh@suse.de>]

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2.6.23-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Jan Beulich <jbeulich@novell.com>

patch aa506dc7b12d03fbf8fd11aab752aed1aadd9c07 in mainline.

i386: avoid temporarily inconsistent pte-s

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.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

--- a/arch/i386/mm/pgtable.c
+++ b/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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