From 9a0417a2d4b082bede8c0495d14d8bb20afaa700 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 10 Aug 2012 17:51:18 +0100 Subject: ARM: 7487/1: mm: avoid setting nG bit for user mappings that aren't present commit 47f1204329237a0f8655f5a9f14a38ac81946ca1 upstream. 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. Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/mm/flush.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/arm/mm') diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 1a8d4aa..8fda9f7 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -236,8 +236,6 @@ 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; -- cgit v1.1