From owner-freebsd-xen@FreeBSD.ORG Sat Oct 23 13:24:54 2010 Return-Path: Delivered-To: freebsd-xen@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A53AE1065679 for ; Sat, 23 Oct 2010 13:24:54 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 372238FC08 for ; Sat, 23 Oct 2010 13:24:53 +0000 (UTC) Received: by wwb24 with SMTP id 24so1786622wwb.31 for ; Sat, 23 Oct 2010 06:24:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=a8w8LeLg+k7egZoUK7nivQdnfmipJv7J5Zh0aPLQLhY=; b=qkUqEttfdvJU6tWD/1XJCffPG97IFI16ipp9ehxmLOiQPT59hiqOEllsKk9DJabSKb XHS16QNswZXdlZVDkbHdYNbWe/h8LtqqSW5OvymekJ2rs3hHppispEw39V6tx/j1EzFk PIJiD+VMmoD6HRom9I+yRL9a2hpLnxrETXs2M= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=nysCKzbKzkZ59R2JExJbq5mwkb5RpnF/fU8l6OUfi5lsuZoYEUJJiRNWKFAdWwsjAe xE7cpwtT2LbEXk4RikiVdGFq+QeGvGg/9/hI8uAGpe+c+EME2SP48Wb+QOXxR0SWCAb1 5X8vtGixvyGoWAE/kG+XILSEs2fTb92mLoHXY= MIME-Version: 1.0 Received: by 10.216.52.135 with SMTP id e7mr3870170wec.98.1287838507385; Sat, 23 Oct 2010 05:55:07 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.216.230.32 with HTTP; Sat, 23 Oct 2010 05:55:07 -0700 (PDT) In-Reply-To: References: Date: Sat, 23 Oct 2010 20:55:07 +0800 X-Google-Sender-Auth: 5dNPs-mf_0XQCIXKFn8SMv0hCUM Message-ID: From: Adrian Chadd To: Linda Messerschmidt Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: "freebsd-xen@FreeBSD.org" Subject: Re: Fatal trap 12 on live migrate X-BeenThere: freebsd-xen@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion of the freebsd port to xen - implementation and usage List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Oct 2010 13:24:54 -0000 Ah, I need to see if I can dig up the stuff Kip told me a while ago about bringing up gdb to actually debug FreeBSD DomU's over the network. Basically, there's a quick hack that can be done to build a gdb-xenserver process which runs in the Dom0 and exports the DomU as a remote gdb debug stub. You can then attach to it from a debugger on a FreeBSD machine and do things like set breakpoints, check process state, etc. It makes debugging so very much easier. I suggest to start - grab the xen 4.0.1 source tarball and see if there's a gdb-xenserver directory (or something gdb'y and xen'y in there.) If so, figure out how to build it. :-) Then email the list with your results and I'll see what I can help you with via email. Note though - I can't really look at any of this stuff until after mid November due to university studies and exams (which is primarily why I've been quiet about the whole Xen thing this year.) Adrian On 23 October 2010 03:31, Linda Messerschmidt wrote: > Hello, > > With 8.1-STABLE (r214217) up and running under Xen 4.0.1 on the > 2.6.32.24 pvops kernel, this command: > > xm migrate freebsd8s localhost > > Produces the following crash: > > kernel trap 12 with interrupts disabled > Kernel page fault with the following non-sleepable locks held: > exclusive sleep mutex intr sources (intr sources) r =3D 0 (0xc051c540) > locked @ /usr/src/sys/i386/i386/intr_machdep.c:190 > KDB: stack backtrace: > X_db_sym_numargs(c0333f0d,c00fbc50,d4667ad4,a,d4667b10,...) at > X_db_sym_numargs+0x146 > kdb_backtrace(be,3,ffffffff,c04e24d4,d4667b64,...) at kdb_backtrace+0x2a > witness_display_spinlock(c0336345,d4667b78,4,1,0,...) at > witness_display_spinlock+0x75 > witness_warn(5,0,c035da1d,c03b4e7c,c234d2a8,...) at witness_warn+0x1fe > trap(d4667bfc) at trap+0x16a > alltraps(c2366cc0,f,d4667c78,c02dc08e,83,...) at alltraps+0x1b > unbind_from_irqhandler(83,d4667cd8,c02d74d3,c22f7780,c22db03c,...) at > unbind_from_irqhandler+0x21 > xencons_suspend(c22f7780,c22db03c,c036c3b8,b5,d4667cc8,...) at > xencons_suspend+0x1e > evtchn_device_upcall(c038d474,c262dc80,2,301,a,...) at > evtchn_device_upcall+0x4e3 > xs_suspend(0,d4667d38,c032bf9f,345,c234d2a8,...) at xs_suspend+0x1fe > fork_exit(c02d9e10,0,d4667d38) at fork_exit+0xb8 > fork_trampoline() at fork_trampoline+0x8 > --- trap 0, eip =3D 0, esp =3D 0xd4667d70, ebp =3D 0 --- > > > Fatal trap 12: page fault while in kernel mode > cpuid =3D 0; apic id =3D 00 > fault virtual address =A0 =3D 0x0 > fault code =A0 =A0 =A0 =A0 =A0 =A0 =A0=3D supervisor read, page not prese= nt > instruction pointer =A0 =A0 =3D 0x21:0x0 > stack pointer =A0 =A0 =A0 =A0 =A0 =3D 0x29:0xd4667c3c > frame pointer =A0 =A0 =A0 =A0 =A0 =3D 0x29:0xd4667c5c > code segment =A0 =A0 =A0 =A0 =A0 =A0=3D base 0x0, limit 0xfffff, type 0x1= b > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=3D DPL 1, pres 1, def32 1= , gran 1 > processor eflags =A0 =A0 =A0 =A0=3D resume, IOPL =3D 0 > current process =A0 =A0 =A0 =A0 =3D 14 (xenwatch) > [thread pid 14 tid 100017 ] > Stopped at =A0 =A0 =A00: =A0 =A0 =A0*** error reading from address 0 *** > > I am no expert but it looks like some sort of null pointer problem? > Maybe it tried to jump to a null address? =A0(eip =3D 0) > > I would like to learn more about the inner workings of DomU FreeBSD. > How could I help debug this? > > Thanks! > _______________________________________________ > freebsd-xen@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-xen > To unsubscribe, send any mail to "freebsd-xen-unsubscribe@freebsd.org" >