Comment 4 for bug 653626

I think I'm seeing the same bug. Reboot, panic or hang a few secons upon kernel loading start. Both acpi=off or nolapic work (but not noapic).

This is in a computer which runs fine in 10.04. Booting 10.10 with either of these, htop and system monitor only shows only one of the four cores (all are shown in 10.04).

I'm using the final 10.10 image for the netbook edition.

CPU is an i5 650. I'm going to run the apport-collect next. The CPU, from lshw, is:

*-cpu
          description: CPU
          product: Intel(R) Core(TM) i5 CPU 650 @ 3.20GHz
          vendor: Intel Corp.
          physical id: 0
          bus info: cpu@0
          version: 6.5.2
          serial: 0002-0652-0000-0000-0000-0000
          slot: XU1
          size: 1199MHz
          capacity: 4GHz
          width: 64 bits
          clock: 133MHz
          capabilities: boot fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp x86-64 constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt aes lahf_lm ida arat tpr_shadow vnmi flexpriority ept vpid cpufreq
          configuration: id=0