I have the same problem. 

Kubuntu edgy 6.10 on a Centrino Duo with ipw3945 wireless. Full configuration of the hardware is here: <a href="http://baheyeldin.com/click/782/5">Toshiba Satellite A100-TA6 with Kubuntu</a>.

Occasionally, when an incoming call from Skype  comes in, (and perhaps when I am on battery), the machine will hang for 30 seconds or so, then everything comes back to normal.

Plain vanilla kernel, with only kqemu tainting it (and perhaps the ipw3945)

$ uname -a
Linux somehost 2.6.17-10-generic #2 SMP Tue Dec 5 22:28:26 UTC 2006 i686 GNU/Linux

Here are two occurances.

[17509010.604000] BUG: soft lockup detected on CPU#0!
[17509010.604000]  <c01491cf> softlockup_tick+0x9f/0xf0  <c012bee1> update_process_times+0x31/0x80
[17509010.604000]  <c0139320> hrtimer_get_res+0x0/0x60  <c0114d13> smp_apic_timer_interrupt+0x53/0x60
[17509010.604000]  <c010413c> apic_timer_interrupt+0x1c/0x30  <c0139320> hrtimer_get_res+0x0/0x60
[17509010.604000]  <c01172c8> hpet_readl+0x8/0x10  <c010e98a> get_offset_hpet+0xa/0x30
[17509010.604000]  <c0106959> do_gettimeofday+0x19/0xc0  <c0139320> hrtimer_get_res+0x0/0x60
[17509010.604000]  <c0126f3d> getnstimeofday+0xd/0x30  <c0135697> sys_clock_gettime+0x77/0x90
[17509010.604000]  <c0102fbb> sysenter_past_esp+0x54/0x79
[17509010.860000] BUG: soft lockup detected on CPU#1!
[17509010.860000]  <c01491cf> softlockup_tick+0x9f/0xf0  <c012bee1> update_process_times+0x31/0x80
[17509010.860000]  <c0114d13> smp_apic_timer_interrupt+0x53/0x60  <c010413c> apic_timer_interrupt+0x1c/0x30
[17509042.700000] ipw3945: Microcode SW error detected.  Restarting.
[17509042.768000] ipw3945: Microcode HW error detected.  Restarting.
[17509043.272000] ipw3945: Error sending LEDS_CMD: time out after 500ms.
[17509043.772000] ipw3945: Error sending ADD_STA: time out after 500ms.
[17509043.772000] ipw3945: Can't stop Rx DMA.
[17509045.184000] ipw3945: Detected geography ABG (11 802.11bg channels, 13 802.11a channels)
[17509055.344000] BUG: soft lockup detected on CPU#1!
[17509055.344000]  <c01491cf> softlockup_tick+0x9f/0xf0  <c012bee1> update_process_times+0x31/0x80
[17509055.344000]  <c0114d13> smp_apic_timer_interrupt+0x53/0x60  <c010413c> apic_timer_interrupt+0x1c/0x30
[17509055.344000]  <c01172c8> hpet_readl+0x8/0x10  <c010e98a> get_offset_hpet+0xa/0x30
[17509055.344000]  <c0106959> do_gettimeofday+0x19/0xc0  <c0139320> hrtimer_get_res+0x0/0x60
[17509055.344000]  <c0126f3d> getnstimeofday+0xd/0x30  <c0135697> sys_clock_gettime+0x77/0x90
[17509055.344000]  <c0102fbb> sysenter_past_esp+0x54/0x79
[17510957.904000] ipw3945: Microcode SW error detected.  Restarting.
[17510958.424000] ipw3945: Error sending LEDS_CMD: time out after 500ms.
[17510959.420000] ipw3945: Can't stop Rx DMA.
[17510960.416000] psmouse.c: TouchPad at isa0060/serio4/input0 lost synchronization, throwing 1 bytes away.
[17510960.860000] ipw3945: Detected geography ABG (11 802.11bg channels, 13 802.11a channels)

Second occurance.

[17576818.040000] BUG: soft lockup detected on CPU#1!
[17576818.040000]  <c01491cf> softlockup_tick+0x9f/0xf0  <c012bee1> update_process_times+0x31/0x80
[17576818.040000]  <c0114d13> smp_apic_timer_interrupt+0x53/0x60  <c010413c> apic_timer_interrupt+0x1c/0x30
[17576818.040000]  <c01172c8> hpet_readl+0x8/0x10  <c010e98a> get_offset_hpet+0xa/0x30
[17576818.040000]  <c0106959> do_gettimeofday+0x19/0xc0  <c0139320> hrtimer_get_res+0x0/0x60
[17576818.040000]  <c0126f3d> getnstimeofday+0xd/0x30  <c0135697> sys_clock_gettime+0x77/0x90
[17576818.040000]  <c0102fbb> sysenter_past_esp+0x54/0x79
[17576818.208000] BUG: soft lockup detected on CPU#0!
[17576818.208000]  <c01491cf> softlockup_tick+0x9f/0xf0  <c012bee1> update_process_times+0x31/0x80
[17576818.208000]  <c0114d13> smp_apic_timer_interrupt+0x53/0x60  <c010413c> apic_timer_interrupt+0x1c/0x30
[17576818.208000]  <c013007b> sys_reboot+0x1b/0x1d0  <c0102fae> sysenter_past_esp+0x47/0x79
[17576849.984000] BUG: warning at drivers/scsi/libata-core.c:3266/ata_pio_complete()
[17576849.984000]  <f8885145> ata_pio_task+0x745/0x7c0 [libata]  <c011cdf8> __wake_up+0x38/0x50
[17576849.984000]  <c0132702> run_workqueue+0x72/0xf0  <f8884a00> ata_pio_task+0x0/0x7c0 [libata]
[17576849.984000]  <c01332e7> worker_thread+0x117/0x140  <c011bde0> default_wake_function+0x0/0x10
[17576849.984000]  <c01331d0> worker_thread+0x0/0x140  <c0135f8b> kthread+0xab/0xe0
[17576849.984000]  <c0135ee0> kthread+0x0/0xe0  <c0101005> kernel_thread_helper+0x5/0x10
[17576849.984000] ipw3945: Microcode SW error detected.  Restarting.
[17576849.988000] ata2: command 0x58 timeout, stat 0x50 host_stat 0x0
[17576850.488000] ipw3945: Error sending LEDS_CMD: time out after 500ms.
[17576850.988000] ipw3945: Error sending ADD_STA: time out after 500ms.
[17576850.988000] ipw3945: Can't stop Rx DMA.