From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Lepton Wu" , "Guenter Roeck" , "Juerg Haefliger" , "Greg Kroah-Hartman" Date: Sun, 11 Feb 2018 04:20:06 +0000 Message-ID: Subject: [PATCH 3.2 79/79] kaiser: Set _PAGE_NX only if supported In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.99-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Lepton Wu 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 Link: https://www.spinics.net/lists/kernel/msg2689835.html Reviewed-by: Guenter Roeck Signed-off-by: Lepton Wu Signed-off-by: Greg Kroah-Hartman (backported from Greg K-H's 4.4 stable-queue) Signed-off-by: Juerg Haefliger Signed-off-by: Ben Hutchings --- arch/x86/mm/kaiser.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -189,6 +189,8 @@ static int kaiser_add_user_map(const voi * requires that not to be #defined to 0): so mask it off here. */ flags &= ~_PAGE_GLOBAL; + if (!(__supported_pte_mask & _PAGE_NX)) + flags &= ~_PAGE_NX; if (flags & _PAGE_USER) BUG_ON(address < FIXADDR_START || end_addr >= FIXADDR_TOP);