RE: 2.6.23.8, ondemand scaling governor: "BUG: soft lockup detected on CPU#0!"

["Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>]

>-----Original Message-----
>From: linux-kernel-owner@vger.kernel.org 
>[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Harald Dunkel
>Sent: Monday, November 19, 2007 4:19 PM
>To: Linux Kernel list
>Subject: 2.6.23.8, ondemand scaling governor: "BUG: soft 
>lockup detected on CPU#0!"
>
>Hi folks,
>
>using the ondemand scaling governour I see some error messages
>in kern.log, e.g.:
>
>Nov 20 01:00:46 bugs kernel: BUG: soft lockup detected on CPU#0!
>Nov 20 01:00:46 bugs kernel:  [<c013cf8d>] softlockup_tick+0x91/0xa6
>Nov 20 01:00:46 bugs kernel:  [<c012269c>] 
>update_process_times+0x3a/0x5d
>Nov 20 01:00:46 bugs kernel:  [<c0131219>] tick_sched_timer+0x115/0x164
>Nov 20 01:00:46 bugs kernel:  [<c012d311>] 
>hrtimer_interrupt+0x102/0x191
>Nov 20 01:00:46 bugs kernel:  [<c0106cd6>] timer_interrupt+0x2e/0x34
>Nov 20 01:00:46 bugs kernel:  [<c013d1f6>] handle_IRQ_event+0x1a/0x3f
>Nov 20 01:00:46 bugs kernel:  [<c013e4e1>] handle_level_irq+0xa8/0xb7
>Nov 20 01:00:46 bugs kernel:  [<c0106367>] do_IRQ+0x53/0x6c
>Nov 20 01:00:46 bugs kernel:  [<c0104853>] common_interrupt+0x23/0x28
>Nov 20 01:00:46 bugs kernel:  [<c011007b>] 
>smp_apic_timer_interrupt+0x1a/0x70
>Nov 20 01:00:46 bugs kernel:  [<c0102a36>] default_idle+0x27/0x39
>Nov 20 01:00:46 bugs kernel:  [<c010234c>] cpu_idle+0x46/0x68
>Nov 20 01:00:46 bugs kernel:  [<c032e9e8>] start_kernel+0x24d/0x252
>Nov 20 01:00:46 bugs kernel:  [<c032e317>] unknown_bootoption+0x0/0x196
>Nov 20 01:00:46 bugs kernel:  =======================
>
>This seems to happen when the load drops below the threshold and
>the ondemand governor changes the CPU from 2GHz to 400MHz. If I use
>the "performance" governor instead, then there is no such message.
>If I set it back to "ondemand", then the message is printed
>immediately.
>
># uname -a
>Linux bugs 2.6.23.8 #1 PREEMPT Sun Nov 18 09:14:13 CET 2007 
>i686 GNU/Linux
># cat /proc/cpuinfo
>processor       : 0
>vendor_id       : GenuineIntel
>cpu family      : 6
>model           : 13
>model name      : Intel(R) Pentium(R) M processor 2.00GHz
>stepping        : 8
>cpu MHz         : 400.000
>cache size      : 2048 KB
>fdiv_bug        : no
>hlt_bug         : no
>f00f_bug        : no
>coma_bug        : no
>fpu             : yes
>fpu_exception   : yes
>cpuid level     : 2
>wp              : yes
>flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr 
>pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe 
>nx bts est tm2
>bogomips        : 798.34
>clflush size    : 64
>
>
>Please mail if I can help to track this down.
>
>

Can you try switching to powersave governor (which should always run CPU
at 400MHz) and see whether you see similar error?

Thanks,
Venki
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