From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miklos Szeredi , Geert Uytterhoeven , Richard Weinberger , Daniel Walter Subject: [PATCH 3.18 176/183] um: Skip futex_atomic_cmpxchg_inatomic() test Date: Sun, 25 Jan 2015 10:08:18 -0800 Message-Id: <20150125180817.810522003@linuxfoundation.org> In-Reply-To: <20150125180810.160428929@linuxfoundation.org> References: <20150125180810.160428929@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Weinberger 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: Greg Kroah-Hartman --- arch/um/Kconfig.common | 1 + 1 file changed, 1 insertion(+) --- a/arch/um/Kconfig.common +++ b/arch/um/Kconfig.common @@ -3,6 +3,7 @@ config UML default y select HAVE_ARCH_AUDITSYSCALL select HAVE_UID16 + select HAVE_FUTEX_CMPXCHG if FUTEX select GENERIC_IRQ_SHOW select GENERIC_CPU_DEVICES select GENERIC_IO