From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: kvm_amd BUG: unable to handle kernel NULL pointer dereference at 00000014 Date: Sun, 06 Mar 2011 12:23:12 +0200 Message-ID: <4D736090.1000300@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Joerg Roedel To: IVAN ANGELOV Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56568 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751811Ab1CFKYs (ORCPT ); Sun, 6 Mar 2011 05:24:48 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 03/04/2011 12:34 AM, IVAN ANGELOV wrote: > Hello, > This provided dmesg message and kernel behavior appear when trying to > run qemu-kvm with kvm_amd module. Without kvm_amd qemu-kvm runs fine > but a slower. I managed to see that this happens with 2.6.38-rc6 , > 2.6.38-rc7 vanilla kernels compiled using kernel-package. OS ubuntu > natty. Using the standard toolchain and gcc from ubuntu: gcc version > 4.5.2 (Ubuntu/Linaro 4.5.2-3ubuntu3) > I reverted to 2.6.37.2 linux kernel, compiled with the very same tools > and machine I use qemu-kvm with kvm_amd module without any problems. > If I can provide some extra info about that please let me know. > This issue also appears with the kernel provided by the Ubuntu > distribution: 2.6.38-5-generic-pae #32-Ubuntu SMP Tue Feb 22 17:48:56 > UTC 2011 i686 athlon i386 GNU/Linux , I suspect it is somehow related > to the 2.6.38 kernel series. > cpuinfo - phenom ii x4 955 mildly overclocked - 4 fields like this is > the whole cpuinfo. c: 65 a1 14 00 00 00 mov %gs:0x14,%eax faults, gsbase == NULL. But arch/x86/include/asm/percpu.h says: #ifdef CONFIG_X86_64 #define __percpu_seg gs #define __percpu_mov_op movq #else #define __percpu_seg fs #define __percpu_mov_op movl #endif So we should be using %fs, not %gs. -- error compiling committee.c: too many arguments to functionb