From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Subject: Re: 9p broken? Date: Tue, 31 Jul 2012 12:47:43 +0530 Message-ID: <874noos8ko.fsf@skywalker.in.ibm.com> References: <50167F9B.5050003@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KVM list To: Avi Kivity , qemu-devel Return-path: In-Reply-To: <50167F9B.5050003@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org Avi Kivity writes: > Having an annoying bug on i386 kvm I decided to debug it buy running an > i386 guest on my x86_64 host, use 9p to access a guest image, and run it > using nested kvm. > > However, 9p appears to be broken: first, the configure test fails (patch > sent). Second, while mount works, ls on the mount point causes qemu to > crash with > > (gdb) bt > #0 error_set (errp=0x7fffe95fb128, fmt=0x5555558d4568 "{ 'class': > 'VirtFSFeatureBlocksMigration', 'data': { 'path': %s, 'tag': %s } }") at > /home/tlv/akivity/qemu/error.c:32 > #1 0x000055555567cb06 in v9fs_attach (opaque=0x7fffe95e3020) at > /home/tlv/akivity/qemu/hw/9pfs/virtio-9p.c:988 > #2 0x000055555561d19f in coroutine_trampoline (i0=1449767888, i1=21845) > at /home/tlv/akivity/qemu/coroutine-ucontext.c:138 > #3 0x00007ffff5a93ef0 in ?? () from /lib64/libc.so.6 > #4 0x00007fffffffce00 in ?? () > #5 0x0000000000000000 in ?? ( > > **errp already points to a VirtFSFeatureBlocksMigration error; > v9fs_attach() has been called a second time (the first time, > understandably, on mount; the second on ls). > Ok we mount with fid uid = (unsigned)~0. So we need to attach again when we do ls as root. I guess we can do that migration block in attach, or we have to do it conditionally. We also can hit the same if we do a path lookup as a different user. -aneesh From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37847) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sw6iL-00075m-Al for qemu-devel@nongnu.org; Tue, 31 Jul 2012 03:17:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sw6iK-0006PI-8W for qemu-devel@nongnu.org; Tue, 31 Jul 2012 03:17:57 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:49099) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sw6iI-0006P0-U0 for qemu-devel@nongnu.org; Tue, 31 Jul 2012 03:17:56 -0400 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 31 Jul 2012 17:17:29 +1000 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q6V79Nlo9568472 for ; Tue, 31 Jul 2012 17:09:23 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q6V7HllZ003954 for ; Tue, 31 Jul 2012 17:17:47 +1000 From: "Aneesh Kumar K.V" In-Reply-To: <50167F9B.5050003@redhat.com> References: <50167F9B.5050003@redhat.com> Date: Tue, 31 Jul 2012 12:47:43 +0530 Message-ID: <874noos8ko.fsf@skywalker.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: [Qemu-devel] 9p broken? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity , qemu-devel Cc: KVM list Avi Kivity writes: > Having an annoying bug on i386 kvm I decided to debug it buy running an > i386 guest on my x86_64 host, use 9p to access a guest image, and run it > using nested kvm. > > However, 9p appears to be broken: first, the configure test fails (patch > sent). Second, while mount works, ls on the mount point causes qemu to > crash with > > (gdb) bt > #0 error_set (errp=0x7fffe95fb128, fmt=0x5555558d4568 "{ 'class': > 'VirtFSFeatureBlocksMigration', 'data': { 'path': %s, 'tag': %s } }") at > /home/tlv/akivity/qemu/error.c:32 > #1 0x000055555567cb06 in v9fs_attach (opaque=0x7fffe95e3020) at > /home/tlv/akivity/qemu/hw/9pfs/virtio-9p.c:988 > #2 0x000055555561d19f in coroutine_trampoline (i0=1449767888, i1=21845) > at /home/tlv/akivity/qemu/coroutine-ucontext.c:138 > #3 0x00007ffff5a93ef0 in ?? () from /lib64/libc.so.6 > #4 0x00007fffffffce00 in ?? () > #5 0x0000000000000000 in ?? ( > > **errp already points to a VirtFSFeatureBlocksMigration error; > v9fs_attach() has been called a second time (the first time, > understandably, on mount; the second on ls). > Ok we mount with fid uid = (unsigned)~0. So we need to attach again when we do ls as root. I guess we can do that migration block in attach, or we have to do it conditionally. We also can hit the same if we do a path lookup as a different user. -aneesh