Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758732AbbGHPRo (ORCPT ); Wed, 8 Jul 2015 11:17:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52024 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758504AbbGHPRn (ORCPT ); Wed, 8 Jul 2015 11:17:43 -0400 Date: Wed, 8 Jul 2015 11:17:38 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Andy Lutomirski , Peter Zijlstra cc: Paul Mackerras , Arnaldo Carvalho de Melo , Kees Cook , Andrea Arcangeli , Vince Weaver , "hillf.zj" , Valdis Kletnieks , linux-kernel@vger.kernel.org Subject: Kernel broken on processors without performance counters Message-ID: User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 763 Lines: 18 Hi I found out that the patch a66734297f78707ce39d756b656bfae861d53f62 breaks the kernel on processors without performance counters, such as AMD K6-3. Reverting the patch fixes the problem. The static key rdpmc_always_available somehow gets set (I couldn't really find out what is setting it, the function set_attr_rdpmc is not executed), cr4_set_bits(X86_CR4_PCE) is executed and that results in a crash on boot when attempting to execute init, because the proecssor doesn't support that bit in CR4. Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/