This is a note to let you know that I've just added the patch titled
ARM: mm: correct pte_same behaviour for LPAE.
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-mm-correct-pte_same-behaviour-for-lpae.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From dde1b65110353517816bcbc58539463396202244 Mon Sep 17 00:00:00 2001
From: Steve Capper <[email protected]>
Date: Fri, 17 May 2013 12:32:55 +0100
Subject: ARM: mm: correct pte_same behaviour for LPAE.
From: Steve Capper <[email protected]>
commit dde1b65110353517816bcbc58539463396202244 upstream.
For 3 levels of paging the PTE_EXT_NG bit will be set for user
address ptes that are written to a page table but not for ptes
created with mk_pte.
This can cause some comparison tests made by pte_same to fail
spuriously and lead to other problems.
To correct this behaviour, we mask off PTE_EXT_NG for any pte that
is present before running the comparison.
Signed-off-by: Steve Capper <[email protected]>
Reviewed-by: Will Deacon <[email protected]>
Cc: Hou Pengyang <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/include/asm/pgtable-3level.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -166,6 +166,23 @@ static inline pmd_t *pmd_offset(pud_t *p
clean_pmd_entry(pmdp); \
} while (0)
+/*
+ * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
+ * that are written to a page table but not for ptes created with mk_pte.
+ *
+ * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
+ * hugetlb_cow, where it is compared with an entry in a page table.
+ * This comparison test fails erroneously leading ultimately to a memory leak.
+ *
+ * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
+ * present before running the comparison.
+ */
+#define __HAVE_ARCH_PTE_SAME
+#define pte_same(pte_a,pte_b) ((pte_present(pte_a) ? pte_val(pte_a) &
~PTE_EXT_NG \
+ : pte_val(pte_a))
\
+ == (pte_present(pte_b) ? pte_val(pte_b) &
~PTE_EXT_NG \
+ : pte_val(pte_b)))
+
#define set_pte_ext(ptep,pte,ext)
cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))
#endif /* __ASSEMBLY__ */
Patches currently in stable-queue which might be from [email protected]
are
queue-3.10/arm-8109-1-mm-modify-pte_write-and-pmd_write-logic-for-lpae.patch
queue-3.10/arm-mm-correct-pte_same-behaviour-for-lpae.patch
queue-3.10/arm-8108-1-mm-introduce-pte-pmd-_isset-and.patch
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