Red Hat Bugzilla – Bug 524040
block device cannot be detached from DomU
Last modified: 2011-01-05 05:10:58 EST
+++ This bug was initially created as a clone of Bug #524039 +++ Description of problem: On a PV DomU with 2.6.31-12.fc12.x86_64 detaching a block device fails, dumping a backtrace to the console. How reproducible: 100% Steps to Reproduce: On Dom0 dd if=/dev/zero of=/var/lib/xen/images/disk1.dsk bs=1 count=1 seek=10G virsh attach-disk rawhide --driver file /var/lib/xen/images/disk1.dsk xvdb Attach will complete successfully and from DomU the new device can be seen and used without any problem. virsh detach-disk rawhide xvdb Actual results: Detach appears to complete successfully from Dom0, but a stack backtrace is dumped to DomU's console and the device is only partially removed. Expected results: Device is completely removed without failure. Additional info: The backtrace general protection fault: 0000 [#1] SMP last sysfs file: /sys/devices/vbd-51728/block/xvdb/size CPU 0 Modules linked in: nfsd lockd nfs_acl auth_rpcgss exportfs sunrpc ip6t_REJECT nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 dm_multipath uinput joydev xen_netfront xen_blkfront [last unloaded: microcode] Pid: 11, comm: xenwatch Tainted: G W 2.6.31-12.fc12.x86_64 #1 RIP: e030:[<ffffffff812136eb>] [<ffffffff812136eb>] debugfs_remove+0x27/0x90 RSP: e02b:ffff88007d461bf0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8800041fb850 RCX: 00000000001a0006 RDX: 0000000000000000 RSI: ffffea000321bfa8 RDI: 6b6b6b6b6b6b6b6b RBP: ffff88007d461c10 R08: 0000000000000000 R09: 00000000e027cfb5 R10: ffffffff81678e0f R11: 0000000000000000 R12: 6b6b6b6b6b6b6b6b R13: ffff88007d461c80 R14: ffff8800798d5520 R15: ffffffffa0005048 FS: 00007f9f6266e7c0(0000) GS:ffffc90000000000(0000) knlGS:0000000000000000 CS: e033 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f97099ac000 CR3: 000000007b978000 CR4: 0000000000002620 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000000 Process xenwatch (pid: 11, threadinfo ffff88007d460000, task ffff88007d4524a0) Stack: ffff88007d461c30 00000000e027cfb5 ffff8800041fb850 0000000000000000 <0> ffff88007d461c40 ffffffff811126bf ffff88007d461c40 00000000e027cfb5 <0> ffff88007d461c70 ffff88007ad3c480 ffff88007d461c70 ffffffff8126ad2c Call Trace: [<ffffffff811126bf>] bdi_unregister+0x36/0x74 [<ffffffff8126ad2c>] unlink_gendisk+0x43/0x75 [<ffffffff811a537b>] del_gendisk+0x9e/0x10d [<ffffffffa000134a>] blkfront_closing+0xad/0x105 [xen_blkfront] [<ffffffffa00017ef>] backend_changed+0x44d/0x52e [xen_blkfront] [<ffffffff8100ec42>] ? check_events+0x12/0x20 [<ffffffff8130fa30>] otherend_changed+0xf3/0x194 [<ffffffff8100ec2f>] ? xen_restore_fl_direct_end+0x0/0x1 [<ffffffff8130e52d>] xenwatch_thread+0x119/0x160 [<ffffffff81081487>] ? autoremove_wake_function+0x0/0x5f [<ffffffff8130e414>] ? xenwatch_thread+0x0/0x160 [<ffffffff81081034>] kthread+0xac/0xb4 [<ffffffff8101312a>] child_rip+0xa/0x20 [<ffffffff81012a90>] ? restore_args+0x0/0x30 [<ffffffff81013120>] ? child_rip+0x0/0x20 Code: 41 5e c9 c3 55 48 89 e5 41 54 53 48 83 ec 10 0f 1f 44 00 00 65 48 8b 04 25 28 00 00 00 48 89 45 e8 31 c0 48 85 ff 49 89 fc 74 4e <48> 8b 5f 68 48 85 db 74 45 48 8b 7b 50 48 85 ff 74 3c 48 81 c7 RIP [<ffffffff812136eb>] debugfs_remove+0x27/0x90 RSP <ffff88007d461bf0> ---[ end trace a7919e7f17c0a729 ]---
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux major release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Major release. This request is not yet committed for inclusion.
Retesting with latest bits shows that this is working now. We should try to identify what fixed it though, and since what revision.
This has been working quite stabling for a while now. Will close this out as current release. We can reopen as 6.1 work if we need to learn more about it later.