[Xen-devel] Re: system freeze when processor.ko is loaded during boot

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

(Stub reply, to make the mail visible to the list - apparently the original
is still sitting in the to-be-approved queue.)

>>> On 08.10.10 at 22:04, Martin Wilck <mwilck@xxxxxxxx> wrote:
> Hello,
> 
> I see a system freeze with xen-unstable and jeremy/xen/2.6.32-next
> kernel when the processor ACPI mocule is loaded during boot on my
> Samsung X50 notebook. I first saw this problem with Xen under OpenSUSE
> 11.3 (https://bugzilla.novell.com/show_bug.cgi?id=623680) with the
> OpenSUSE hypervisor and kernel.
> 
> So far, I have found out the following:
> 
>  - no problem with OpenSUSE default kernel
>  - no problem with Xen if I don't load processor.ko
>  - no problem with "max_cstate=1" hypervisor parameter (but max_cstate=2
> freezes)
> 
>  - when the freeze happens, I am usually seeing some unreleated messages
> about USB or SATA device initialization. No keys at all are working,
> sometimes the disk LED stays on without the disk making noises. I
> haven't been able to see any hypervisor messages (even with "vga=keep";
> unfortunately the system has no serial port). The Xen "watchdog"
> parameter causes the machine to reboot without any messages.
> 
>  - The weirdest thing is that once the system has booted, I seem to be
> able to load processor.ko without problems (at least the system doesn't
> freeze, even if I let it idle for a long time or if I do normal work
> under X). With the SUSE hypervisor + kernel I was even able to verify
> that cpuidle was working and C3 was being used (with xen-unstable, I
> couldn't get xenpm to work so far).
> 
> - However if processor.ko is loaded during boot, the system always
> freezes (100% reproducable). I tried loading it in the initrd (SUSE
> default) and early after mounting the root FS (autoloaded by udev I
> think), and even compiling it into the kernel proper (tried that only
> with the jeremy kernel). In all cases, the system freezes hard.
> 
> Probably the freeze occurs when the CPU enters a deep C-state while some
> HW initialization is going on at boot time.
> 
> I am a little out of clues how to debug this further, any hints would be
> welcome.
> 
> The info below was taken with the normal OpenSUSE kernel.
> 
> Thanks for any hints
> Martin
> 
> martin@athene:~$ cat /proc/cpuinfo
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 13
> model name      : Intel(R) Pentium(R) M processor 2.13GHz
> stepping        : 8
> cpu MHz         : 800.000
> 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 apic sep mtrr pge
> mca cmov clflush dts acpi mmx fxsr sse sse2 ss tm pbe up bts est tm2
> bogomips        : 1596.03
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 32 bits physical, 32 bits virtual
> power management:
> 
> martin@athene:~$ cat /proc/acpi/processor/CPU0/info
> processor id:            0
> acpi id:                 0
> bus mastering control:   yes
> power management:        yes
> throttling control:      yes
> limit interface:         yes
> 
> martin@athene:~$ cat /proc/acpi/processor/CPU0/power
> active state:            C0
> max_cstate:              C8
> maximum allowed latency: 2000000000 usec
> states:
>     C1:                  type[C1] promotion[--] demotion[--]
> latency[001] usage[00001563] duration[00000000000000000000]
>     C2:                  type[C2] promotion[--] demotion[--]
> latency[001] usage[00308057] duration[00000000002512350868]
>     C3:                  type[C3] promotion[--] demotion[--]
> latency[085] usage[00126109] duration[00000000000772728489]
>     C4:                  type[C3] promotion[--] demotion[--]
> latency[185] usage[00537539] duration[00000000008753288513]
> m
> 
> [    3.345147] processor_driver-0392 [00] processor_get_info    : Bus
> mastering arbitration control present
> [    3.345187] processor_driver-0474 [00] processor_get_info    :
> Processor [0:0]
> [    3.345215] processor_throttling-1141 [00] processor_get_throttli:
> pblk_address[0x00001010] duty_offset[3] duty_width[1]
> [    3.345233] processor_throttling-1187 [00] processor_get_throttli:
> Found 2 throttling states
> [    3.345246] processor_throttling-0657 [00] processor_get_throttli:
> Throttling state is T0 (1000% throttling applied)
> [    3.345585] processor_idle-0526 [00] processor_get_power_in: Found 4
> power states
> [    3.345931] processor_throttling-0218 [00] processor_throttling_i:
> Assume no T-state coordination
> [   82.129875] processor_perflib-0349 [00] processor_get_performa: Found
> 6 performance states
> [   82.129889] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 0
> [   82.129901] processor_perflib-0385 [00] processor_get_performa: State
> [0]: core_frequency[2133] power[27000] transition_latency[10]
> bus_master_latency[10] control[0x1029] status[0x1029]
> [   82.129918] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 1
> [   82.129928] processor_perflib-0385 [00] processor_get_performa: State
> [1]: core_frequency[1867] power[24000] transition_latency[10]
> bus_master_latency[10] control[0xe25] status[0xe25]
> [   82.129945] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 2
> [   82.129955] processor_perflib-0385 [00] processor_get_performa: State
> [2]: core_frequency[1600] power[21000] transition_latency[10]
> bus_master_latency[10] control[0xc20] status[0xc20]
> [   82.129972] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 3
> [   82.129982] processor_perflib-0385 [00] processor_get_performa: State
> [3]: core_frequency[1333] power[19000] transition_latency[10]
> bus_master_latency[10] control[0xa1c] status[0xa1c]
> [   82.129998] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 4
> [   82.130009] processor_perflib-0385 [00] processor_get_performa: State
> [4]: core_frequency[1067] power[16000] transition_latency[10]
> bus_master_latency[10] control[0x817] status[0x817]
> [   82.130025] processor_perflib-0367 [00] processor_get_performa:
> Extracting state 5
> [   82.130035] processor_perflib-0385 [00] processor_get_performa: State
> [5]: core_frequency[800] power[13000] transition_latency[10]
> bus_master_latency[10] control[0x612] status[0x612]
> [   82.130173] processor_perflib-0486 [00] processor_notify_smm  : No
> SMI port or pstate_control



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