Comment 14 for bug 240071

I too am experiencing this problem with my ubuntu XEN system.
setting vcpus = 1 in my domU xen config file seems to have successfully worked around the problem.

The problem appeared immediately following a kernel upgrade and a dom0 distro upgrade from dapper to hardy.
old kernel 2.6.16.13-xen working correctly (compiled by hand)
new kernel 2.6.24-23-xen ubuntu hardy packaged kernel has the soft lockup problems.

The domU is still dapper, totally unchanged.

Here are some details about my setup:

It is an Intel Pentium D dual-core cpu
3Gigs of RAM
Intel chipsets and dual Intel onboard NICs
headless, racked server, no graphics drivers

lspci:
00:00.0 Host bridge: Intel Corporation E7230/3000/3010 Memory Controller Hub (rev 81)
00:01.0 PCI bridge: Intel Corporation E7230/3000/3010 PCI Express Root Port (rev 81)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01)
00:1c.4 PCI bridge: Intel Corporation 82801GR/GH/GHM (ICH7 Family) PCI Express Port 5 (rev 01)
00:1c.5 PCI bridge: Intel Corporation 82801GR/GH/GHM (ICH7 Family) PCI Express Port 6 (rev 01)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01)
00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01)
02:00.0 PCI bridge: Intel Corporation 6702PXH PCI Express-to-PCI Bridge A (rev 09)
02:00.1 PIC: Intel Corporation 6700/6702PXH I/OxAPIC Interrupt Controller A (rev 09)
03:01.0 SCSI storage controller: Marvell Technology Group Ltd. MV88SX6081 8-port SATA II PCI-X Controller (rev 09)
04:00.0 Ethernet controller: Intel Corporation 82573E Gigabit Ethernet Controller (Copper) (rev 03)
04:00.3 Serial controller: Intel Corporation Active Management Technology - SOL (rev 03)
04:00.4 IPMI SMIC interface: Intel Corporation 82573E KCS (Active Management) (rev 03)
05:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet Controller
0a:00.0 VGA compatible controller: ATI Technologies Inc Rage XL (rev 27)
0a:04.0 RAID bus controller: VIA Technologies, Inc. VT6421 IDE RAID Controller (rev 50)

Jan 26 04:49:48 infocentral kernel: [ 5849.193197] BUG: soft lockup - CPU#1 stuck for 11s! [postmaster:9944]
Jan 26 04:49:48 infocentral kernel: [ 5849.193224]
Jan 26 04:49:48 infocentral kernel: [ 5849.193230] Pid: 9944, comm: postmaster Not tainted (2.6.24-23-xen #1)
Jan 26 04:49:48 infocentral kernel: [ 5849.193236] EIP: 0061:[<c03279d7>] EFLAGS: 00000282 CPU: 1
Jan 26 04:49:48 infocentral kernel: [ 5849.193248] EIP is at _spin_lock+0x7/0x10
Jan 26 04:49:48 infocentral kernel: [ 5849.193253] EAX: c1c31b2c EBX: 00000000 ECX: c1c31b20 EDX: 00000270
Jan 26 04:49:48 infocentral kernel: [ 5849.193257] ESI: 51926067 EDI: 00000000 EBP: c0477158 ESP: e94dfddc
Jan 26 04:49:48 infocentral kernel: [ 5849.193261] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0069
Jan 26 04:49:48 infocentral kernel: [ 5849.193269] CR0: 8005003b CR2: b7c4e410 CR3: 2ac1b000 CR4: 00000660
Jan 26 04:49:48 infocentral kernel: [ 5849.193275] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
Jan 26 04:49:48 infocentral kernel: [ 5849.193281] DR6: ffff0ff0 DR7: 00000400
Jan 26 04:49:48 infocentral kernel: [ 5849.193286] [<c016bcc8>] __do_fault+0x3b8/0x6b0
Jan 26 04:49:48 infocentral kernel: [ 5849.193307] [<c0170c69>] handle_mm_fault+0x249/0x1350
Jan 26 04:49:48 infocentral kernel: [ 5849.193318] [<c0107ec5>] local_clock+0x55/0xa0
Jan 26 04:49:48 infocentral kernel: [ 5849.193328] [<c0329576>] do_page_fault+0x366/0xe90
Jan 26 04:49:48 infocentral kernel: [ 5849.193337] [<c02a9357>] sys_recv+0x37/0x40
Jan 26 04:49:48 infocentral kernel: [ 5849.193347] [<c02a98c6>] sys_socketcall+0x1a6/0x2b0
Jan 26 04:49:48 infocentral kernel: [ 5849.193356] [<c0329210>] do_page_fault+0x0/0xe90
Jan 26 04:49:48 infocentral kernel: [ 5849.193362] [<c0327eb5>] error_code+0x35/0x40
Jan 26 04:49:48 infocentral kernel: [ 5849.193370] [<c0320000>] vcc_remove_socket+0x10/0xa0