As John suggested, booting with clocksource=acpi_pm works around the issue. I couldn't reproduce this at all when I boot with init=/bin/sh. That happens both on 2.6.30-rc2 and -rc3. This actually happens relatively late in boot. I also noticed that it seems to always happen during the ACPI messages in that "power states" area. So, I tried booting to /bin/sh again, waiting a few seconds, and doing 'modprobe processor'. Bingo. I got the trace right when I did the modprobe. It doesn't look like it comes from the prinks themselves though: printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id); for (i = 1; i <= pr->power.count; i++) if (pr->power.states[i].valid) printk(" C%d[C%d]", i, pr->power.states[i].type); printk(")\n"); Any ideas? Apr 23 09:04:47 nimitz kernel: [ 13.208679] sd 6:0:0:0: [sdc] Attached SCSI disk Apr 23 09:04:47 nimitz kernel: [ 13.653314] ACPI: SSDT bf6e1b32 002C4 (v01 PmRef Cpu0Ist 00000100 INTL 20050513) Apr 23 09:04:47 nimitz kernel: [ 13.669448] ACPI: SSDT bf6e1e7b 0085E (v01 PmRef Cpu0Cst 00000100 INTL 20050513) Apr 23 09:04:47 nimitz kernel: [ 299.093892] ACPI: CPU0 (power states:<3>BUG: soft lockup - CPU#1 stuck for 266s! [modprobe:3193] Apr 23 09:04:47 nimitz kernel: [ 299.100292] Modules linked in: button(+) processor(+) ohci1394 ieee1394 uhci_hcd ehci_hcd thermal fan fuse usb_storage usb_libusual usbcore Apr 23 09:04:47 nimitz kernel: [ 299.100302] Apr 23 09:04:47 nimitz kernel: [ 299.100305] Pid: 3193, comm: modprobe Not tainted (2.6.30-rc3-dirty #327) 7659A71 Apr 23 09:04:47 nimitz kernel: [ 299.100308] EIP: 0073:[<08049942>] EFLAGS: 00000246 CPU: 1 Apr 23 09:04:47 nimitz kernel: [ 299.100311] EIP is at 0x8049942 Apr 23 09:04:47 nimitz kernel: [ 299.100313] EAX: 0000006b EBX: 0000002f ECX: 0000006b EDX: 0804e198 Apr 23 09:04:47 nimitz kernel: [ 299.100315] ESI: 0804e268 EDI: 000000a1 EBP: bf8f73b8 ESP: bf8f7390 -- Dave -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html