From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757965AbbA2GzX (ORCPT ); Thu, 29 Jan 2015 01:55:23 -0500 Received: from terminus.zytor.com ([198.137.202.10]:46464 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751328AbbA2GzR (ORCPT ); Thu, 29 Jan 2015 01:55:17 -0500 Date: Wed, 28 Jan 2015 22:54:36 -0800 From: tip-bot for Boris Ostrovsky Message-ID: Cc: boris.ostrovsky@oracle.com, mingo@kernel.org, hpa@zytor.com, bp@suse.de, tglx@linutronix.de, james@dingwall.me.uk, linux-kernel@vger.kernel.org Reply-To: mingo@kernel.org, bp@suse.de, hpa@zytor.com, boris.ostrovsky@oracle.com, james@dingwall.me.uk, linux-kernel@vger.kernel.org, tglx@linutronix.de In-Reply-To: <1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com> References: <1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86, microcode: Return error from driver init code when loader is disabled Git-Commit-ID: da63865a01c6384d459464e5165d95d4f04878d8 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: da63865a01c6384d459464e5165d95d4f04878d8 Gitweb: http://git.kernel.org/tip/da63865a01c6384d459464e5165d95d4f04878d8 Author: Boris Ostrovsky AuthorDate: Tue, 27 Jan 2015 21:21:09 -0500 Committer: Borislav Petkov CommitDate: Wed, 28 Jan 2015 09:23:40 +0100 x86, microcode: Return error from driver init code when loader is disabled Commits 65cef1311d5d ("x86, microcode: Add a disable chicken bit") and a18a0f6850d4 ("x86, microcode: Don't initialize microcode code on paravirt") allow microcode driver skip initialization when microcode loading is not permitted. However, they don't prevent the driver from being loaded since the init code returns 0. If at some point later the driver gets unloaded this will result in an oops while trying to deregister the (never registered) device. To avoid this, make init code return an error on paravirt or when microcode loading is disabled. The driver will then never be loaded. Signed-off-by: Boris Ostrovsky Link: http://lkml.kernel.org/r/1422411669-25147-1-git-send-email-boris.ostrovsky@oracle.com Reported-by: James Digwall Cc: stable@vger.kernel.org # 3.18 Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 15c2909..36a8361 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -552,7 +552,7 @@ static int __init microcode_init(void) int error; if (paravirt_enabled() || dis_ucode_ldr) - return 0; + return -EINVAL; if (c->x86_vendor == X86_VENDOR_INTEL) microcode_ops = init_intel_microcode();