From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932978AbbA2KWV (ORCPT ); Thu, 29 Jan 2015 05:22:21 -0500 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:44737 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756380AbbA2JAv (ORCPT ); Thu, 29 Jan 2015 04:00:51 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Richard Weinberger , Jiri Slaby Subject: [PATCH 3.12 127/176] um: Skip futex_atomic_cmpxchg_inatomic() test Date: Wed, 28 Jan 2015 15:29:17 +0100 Message-Id: <8f8c6ea486fc69e3020fe99718d9c4b38cbaf8ba.1422455352.git.jslaby@suse.cz> X-Mailer: git-send-email 2.2.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Richard Weinberger 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit f911d731054ab3d82ee72a16b889e17ca3a2332a upstream. futex_atomic_cmpxchg_inatomic() does not work on UML because it triggers a copy_from_user() in kernel context. On UML copy_from_user() can only be used if the kernel was called by a real user space process such that UML can use ptrace() to fetch the value. Reported-by: Miklos Szeredi Suggested-by: Geert Uytterhoeven Signed-off-by: Richard Weinberger Tested-by: Daniel Walter Signed-off-by: Jiri Slaby --- arch/um/Kconfig.common | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common index 8ddea1f8006a..0228a6ab9b18 100644 --- a/arch/um/Kconfig.common +++ b/arch/um/Kconfig.common @@ -7,6 +7,7 @@ config UML bool default y select HAVE_UID16 + select HAVE_FUTEX_CMPXCHG if FUTEX select GENERIC_IRQ_SHOW select GENERIC_CPU_DEVICES select GENERIC_IO -- 2.2.2