From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Clark Subject: Re: Unstableness in grant table block drivers Date: Wed, 20 Apr 2005 11:52:35 -0700 Message-ID: References: <20050416153922.GH27157@us.ibm.com> <20050418205103.GC19115@us.ibm.com> Reply-To: cwc22@cam.ac.uk Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20050418205103.GC19115@us.ibm.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ryan Harper Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Ryan Many thanks for taking the traces. I've located a bug in the block backend that may or may not be the required fix -- it's a move of a single line, see the patch below. c. Signed-off-by: Christopher Clark diff -Nru a/linux-2.6.11-xen-sparse/drivers/xen/blkback/blkback.c b/linux-2.6.11-xen-sparse/drivers/xen/blkback/blkback.c --- a/linux-2.6.11-xen-sparse/drivers/xen/blkback/blkback.c 2005-04-20 11:31:20 -07:00 +++ b/linux-2.6.11-xen-sparse/drivers/xen/blkback/blkback.c 2005-04-20 11:31:20 -07:00 @@ -516,11 +516,11 @@ for ( i =3D 0; i < nseg; i++ ) { + fas =3D req->frame_and_sects[i]; #ifdef CONFIG_XEN_BLKDEV_GRANT seg[i].buf =3D (aop[i].u.map_grant_ref.dev_bus_addr << PAGE_SHIFT= ) | (blkif_first_sect(fas) << 9); #else - fas =3D req->frame_and_sects[i]; seg[i].buf =3D (fas & PAGE_MASK) | (blkif_first_sect(fas) << 9); seg[i].nsec =3D blkif_last_sect(fas) - blkif_first_sect(fas) + 1; if ( seg[i].nsec <=3D 0 ) On 4/18/05, Ryan Harper wrote: > * Christopher Clark [2005-04-18 11:39]: > > Ryan and Anthony: I've attached a patch that I'd like you to apply to > > your unstable tree -- it just printk's almost everything so I can get > > an idea of the code path you're running. > > Alternatively, the three .c files modified by the patch are also > > attached - they're taken from 2005-04-14 unstable and you should be > > able to just replace the files in your tree. > > > > After changing your tree and rebuilding, please send the console logs > > from boot onwards for xen/dom0 and domU, in a uniprocessor > > configuration, both with and without using grant tables for block > > transport. >=20 > I've applied the patch and I have a bunch of logs. >=20 > 1) domU boot output when dom0up boots domUup > 2) domU boot output when dom0up boots domUsmp > 3) xen console output for 1) and 2) > 4) domU boot output when dom0smp boots domUup > 5) domU boot output when dom0smp boots domUsmp > 6) xen console output for 4) and 5) >=20 > In the above cases, dom0up was simulated with maxcpu=3D1, as I still don'= t > have that UP box setup. If you can't find anything in these logs then > I'll go get a real UP box and repeat the dumps. >=20 > -- > Ryan Harper > Software Engineer; Linux Technology Center > IBM Corp., Austin, Tx > (512) 838-9253 T/L: 678-9253 > ryanh@us.ibm.com >=20 >=20 >