From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wright <chrisw@sous-sol.org>
Subject: Re: kvm: unable to handle kernel NULL pointer dereference
Date: Thu, 5 Jun 2008 11:34:47 -0700
Message-ID: <20080605183447.GL30402@sequoia.sous-sol.org>
References: <20080601084802.GA3146@yamamaya.is-a-geek.org> <4846716E.5000506@qumranet.com> <20080604181019.GB10897@yamamaya.is-a-geek.org> <20080605042535.GC30402@sequoia.sous-sol.org> <20080605060931.GA11704@yamamaya.is-a-geek.org> <20080605072728.GF30402@sequoia.sous-sol.org> <20080605182847.GA12176@yamamaya.is-a-geek.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
To: Tobias Diedrich <ranma+kernel@tdiedrich.de>,
	Chris Wright <chrisw@sous-sol.org>,
	Avi Kivity <avi@qumranet.com>, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Roedel, Joerg" <Jo
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S1762158AbYFESfy@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <20080605182847.GA12176@yamamaya.is-a-geek.org>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

* Tobias Diedrich (ranma+kernel@tdiedrich.de) wrote:
> PM: Creating hibernation image: 
> PM: Need to copy 126181 pages
> PM: Normal pages needed: 126181 + 1024 + 38, available pages: 397721
> x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
> svm_cpu_init: svm_data is NULL on 0

Yeah, this is broken.  What happens is:

suspend:
  hardware_disable
    svm_hardware_disable
      kfree(svm_data)
      per_cpu(svm_data) = NULL

resume:
  hardware_enable
    svm_hardware_enable
      if(!svm_data) printk("svm_cpu_init: svm_data is NULL on 0")

at this point it is broken.

Same would happen on an SMP box by simply doing offline/online of a CPU.
This is definitely busted, looking into a patch.

thanks,
-chris