Messages in this thread | | | Date | Sun, 20 Apr 2008 00:52:08 +0300 | From | Pekka Paalanen <> | Subject | [BUG] CPU hotplug reboots machine (Re: [PATCH] Fix SMP alternatives : use mutex instead of spinlock, text_poke is sleepable) |
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On Sun, 20 Apr 2008 00:06:57 +0300 Pekka Paalanen <pq@iki.fi> wrote:
> Mathieu, > > thank you for the quick reply. Your patch did not apply on sched-devel/latest > so I made the changes by hand, resulting patch here. The change was in the > context lines, which made `patch' fail, e.g. __FUNCTION__ -> __func__. > Now my enter_uniprocessor(), that disables all but the first cpu, works fine. > > My next quest is, why attempting to re-enable the cpus makes the whole > machine reboot after a short hang.
Uhh, I don't have the faintest idea why this happens or how to debug it.
A simple echo 0 > /sys/devices/system/cpu/cpu1/online echo 1 > /sys/devices/system/cpu/cpu1/online
produces the following kernel log (netconsole) and then after a couple second hang the machine reboots:
[ 84.678357] console [netcon0] enabled [ 84.679568] netconsole: network logging started [ 232.812335] CPU 1 is now offline [ 232.812678] lockdep: fixing up alternatives. [ 232.813051] SMP alternatives: switching to UP code [ 268.447582] lockdep: fixing up alternatives. [ 268.447903] SMP alternatives: switching to SMP code [ 268.459462] Booting processor 1/1 ip 6000
My kernel is sched-devel/latest git tree with Desnoyers' patch, and my patches that touch only arch/x86/mm/mmio-mod.c. The machine is Thinkpad T61 with:
processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz stepping : 10 cpu MHz : 2001.000 cache size : 4096 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm ida bogomips : 3997.03 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management:
processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz stepping : 10 cpu MHz : 2001.000 cache size : 4096 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 1 initial apicid : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm ida bogomips : 3991.26 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management:
Any help would be appreciated.
Thanks.
-- Pekka Paalanen http://www.iki.fi/pq/
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