From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:35324 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965212AbeALVb7 (ORCPT ); Fri, 12 Jan 2018 16:31:59 -0500 Received: by mail-pf0-f193.google.com with SMTP id t12so5321292pfg.2 for ; Fri, 12 Jan 2018 13:31:59 -0800 (PST) From: Lepton Wu To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, groeck@chromium.org, hshan@google.com, Lepton Wu Subject: [PATCH 4.4-stable] kaiser: Set _PAGE_NX only if supported Date: Fri, 12 Jan 2018 13:31:50 -0800 Message-Id: <20180112213150.250374-1-ytht.net@gmail.com> Sender: stable-owner@vger.kernel.org List-ID: This finally resolve crash if loaded under qemu + haxm. Haitao Shan pointed out that the reason of that crash is that NX bit get set for page tables. It seems we missed checking if _PAGE_NX is supported in kaiser_add_user_map See https://www.spinics.net/lists/kernel/msg2689835.html for details. Signed-off-by: Lepton Wu --- arch/x86/mm/kaiser.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 6a7a77929a8c..936672f71139 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -198,6 +198,10 @@ static int kaiser_add_user_map(const void *__start_addr, unsigned long size, * requires that not to be #defined to 0): so mask it off here. */ flags &= ~_PAGE_GLOBAL; + /* If CPU doesn't support NX, don't set it. */ + if (!(__supported_pte_mask & _PAGE_NX)) + flags &= ~_PAGE_NX; + for (; address < end_addr; address += PAGE_SIZE) { target_address = get_pa_from_mapping(address); -- 2.16.0.rc1.238.g530d649a79-goog