smp bug in kvm-69

hi,
we just noticed that while we run a guest with 4vcpu (the host has 4 core):
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3278 ? Sl 2138:49 /usr/bin/qemu-kvm -M pc -m 2048 -smp 4
-monitor pty -boot c -hda /dev/VolGroup00/centos-i386-root -hdb /dev/VolGroup00/centos-i386-swap -hdc /dev/md2 -net nic,macaddr=00:16:3e:58:66:7b,vlan=0 -net tap,fd=11,script=,vlan=0,ifname=vnet0 -usb -usbdevice tablet -vnc 127.0.0.1:0
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the guest only see 3 cpu?:
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# cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 2
model name      : QEMU Virtual CPU version 0.9.1
stepping        : 3
cpu MHz         : 2399.968
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 de pse tsc msr pae mce cx8 apic mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 syscall nx lm pni
bogomips        : 4806.74

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 2
model name : QEMU Virtual CPU version 0.9.1
stepping : 3
cpu MHz : 2399.968
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 de pse tsc msr pae mce cx8 apic mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 syscall nx lm pni
bogomips : 4800.27

processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 2
model name : QEMU Virtual CPU version 0.9.1
stepping : 3
cpu MHz : 2399.968
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 de pse tsc msr pae mce cx8 apic mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 syscall nx lm pni
bogomips : 4797.91
-----------------------------------------

  Levente                               "Si vis pacem para bellum!"

Does this happen every time? Is the host loaded when you start the guest with some other task?

It may be that there is some guest timeout during startup which causes the cpu to go missing.

Do not meddle in the internals of kernels, for they are subtle and quick to panic.

no just sometimes, sometimes nont

you knows:-)

  Levente                               "Si vis pacem para bellum!"