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authorWill Deacon <will.deacon@arm.com>2012-08-10 17:51:18 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-08-11 09:15:59 +0100
commit47f1204329237a0f8655f5a9f14a38ac81946ca1 (patch)
tree863782a6d372973865860a3e55d79a0cbd01880d /arch/arm/mm
parent237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b (diff)
ARM: 7487/1: mm: avoid setting nG bit for user mappings that aren't present
Swap entries are encoding in ptes such that !pte_present(pte) and pte_file(pte). The remaining bits of the descriptor are used to identify the swapfile and offset within it to the swap entry. When writing such a pte for a user virtual address, set_pte_at unconditionally sets the nG bit, which (in the case of LPAE) will corrupt the swapfile offset and lead to a BUG: [ 140.494067] swap_free: Unused swap offset entry 000763b4 [ 140.509989] BUG: Bad page map in process rs:main Q:Reg pte:0ec76800 pmd:8f92e003 This patch fixes the problem by only setting the nG bit for user mappings that are actually present. Cc: <stable@vger.kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/flush.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 77458548e03..40ca11ed6e5 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -231,8 +231,6 @@ void __sync_icache_dcache(pte_t pteval)
struct page *page;
struct address_space *mapping;
- if (!pte_present_user(pteval))
- return;
if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
/* only flush non-aliasing VIPT caches for exec mappings */
return;