From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Fwd: Re: kvm-31 seg fault Date: Wed, 25 Jul 2007 06:22:19 +0300 Message-ID: <46A6C1EB.4040104@qumranet.com> References: <200707242202.05192.chris2553@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Chris Clayton Return-path: In-Reply-To: <200707242202.05192.chris2553-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Chris Clayton wrote: > Forgot to cc this to the list, sorry > ---------- Forwarded Message ---------- > > Subject: Re: [kvm-devel] kvm-31 seg fault > Date: Tuesday 24 July 2007 > From: Chris Clayton > To: Avi Kivity > > Hi again Avi, > > On Sunday 22 July 2007, you wrote: > >> Chris Clayton wrote: >> >>> On Sunday 22 July 2007, you wrote: >>> >>>> Chris Clayton wrote: >>>> >>>>> Hi, >>>>> >>>>> I'm getting a seg fault running kvm-31 on linux-2.6.22.1-cfs-v19 and >>>>> linux-2.6.22-git17. >>>>> >>>>> If I use the kvm-31 kernel modules with qemu from kvm-29, all is OK >>>>> Also, running "non-kvm" guests, such as Windows ME, works fine with >>>>> kvm-31. >>>>> >>>>> I have an strace log but its over 99 Kilobytes, so I haven't attached >>>>> it to this mail. More than happy to compress it and send it by private >>>>> mail, if required. >>>>> >>>>> I'm not subscribed, so please cc me. >>>>> >>>> Please send it to me. What guest are you running? Is the host 32-bit >>>> or 64-bit? >>>> >>> Attached is the log from 2.6.22-git17 >>> >>> The host is 32bit and the guest is freebsd-6.2 although I get the same >>> seg fault with slackware 10.2 and damn small linux 3.1 (all 32 bit). >>> >> Unfortunately that doesn't help. Can you generate a core ('ulimit -c >> unlimited' may help) and get a stacktrace from gdb? >> > > I've been doing some more digging around here and thought I'd report my > findings. I've found that under kvm 31 and 33, qemu-system-x86_64 always > fails with a seg fault when the (__thread) variable vcpu_env (declared at > line 33 of qemu-kvm.c) is accessed in kvm_update_interrupt_request(). I've > inserted useless statements (printf()s and assignments) at the head of the > function, and always get the seg fault at the first access to the variable. > > I'm building qemu with gcc-3.4.6, but to eliminate a fault in that compiler, > I've also built the application on my laptop with gcc-3.3.6 and copied the > binary over to my desktop machine. I still get the seg fault. > What's the host distro and glibc version? Perhaps they're too old to support __thread? > Sorry if this is just noise on your line, but I thought I'd send it just in > case it's useful. > > It isn't noise, this is helping us getting kvm better. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/