Donald, Shane, Thanks for reporting this. > > I also tried suggested /vmlinuz-4.3.0-rc3 parameter in grub: > > "cpu_init_udelay=10000" > > which did not help getting missing CPU back online.
right, if the issue is caused by the patch below, that cmdline will not help. > Did you try reverting the "x86/smpboot: Remove APIC.wait_for_init_deassert > and atomic init_deasserted" patch? Yes, please let me know if reverting that patch helps you too. You have similar hardware: Shane: smpboot: CPU0: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz (fam: 06, model: 0f, stepping: 06) Donald: CPU : Intel Core 2 CPU 6600 @ 2.4GHz I think I can get ahold of a core2 6xxx box tomorrow. Please send me your .config directly, and I'll see if I can reproduce the issue. thanks, -Len N�����r��y����b�X��ǧv�^�){.n�+����{����zX����ܨ}���Ơz�&j:+v�������zZ+��+zf���h���~����i���z��w���?�����&�)ߢf��^jǫy�m��@A�a��� 0��h���i