From e8c6226d483cb28f55cab718065ea1b7226d40e8 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 29 Jul 2016 09:30:10 -0700 Subject: [PATCH] x86/pkeys: Add fault handling for PF_PK page fault bit PF_PK means that a memory access violated the protection key access restrictions. It is unconditionally an access_error() because the permissions set on the VMA don't matter (the PKRU value overrides it), and we never "resolve" PK faults (like how a COW can "resolve write fault). Signed-off-by: Dave Hansen Acked-by: Mel Gorman Cc: linux-arch@vger.kernel.org Cc: Dave Hansen Cc: arnd@arndb.de Cc: linux-api@vger.kernel.org Cc: linux-mm@kvack.org Cc: luto@kernel.org Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/20160729163010.DD1FE1ED@viggo.jf.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/fault.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index dc8023060456..b88d8acb3ab5 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1112,6 +1112,15 @@ access_error(unsigned long error_code, struct vm_area_struct *vma) { /* This is only called for the current mm, so: */ bool foreign = false; + + /* + * Read or write was blocked by protection keys. This is + * always an unconditional error and can never result in + * a follow-up action to resolve the fault, like a COW. + */ + if (error_code & PF_PK) + return 1; + /* * Make sure to check the VMA so that we do not perform * faults just to hit a PF_PK as soon as we fill in a -- 2.20.1