Hi jayachandranc, sorry to bother you. we are porting linux 2.6.32.41 smp onto xlp416 A2,but got some problems when booting. We found that , if configured the number of cpus with less that 12 , the linux went well, while when we configured cpus with 16, system would be verly likely to hang on somewhere randomly. In order to find what happened, we added some code in timer interrupt handler, to check that if each cpu is still alive by kstat_irqs_cpu(7, cpu), and found that, when system is abnormal, there would be one cpu with interrupt disabled (kstat_irqs_cpu(7, cpu) is not increaing). So we send nmi ipi to the dead cpu, to dump the register and stack on it. And we found out that, the reason for hanging is cpu trap instruction: 1) cpu2 nmi trigger! dump... current running task:khelper on cpu2 epc : ffffffffc10201b4 kernel_execve+0x4/0x30 ra : ffffffffc1064398 ____call_usermodehelper+0x110/0x120 Status: 5448ffe7 KX SX UX KERNEL ERL EXL IE Cause : 40009008 BadVA : 0000000000000000 ErroEPC : ffffffff80000180 Call Trace: [<ffffffffc10201b4>] kernel_execve+0x4/0x30 [<ffffffffc1064398>] ____call_usermodehelper+0x110/0x120 [<ffffffffc101c598>] kernel_thread_helper+0x10/0x18 epc ffffffffc10201b4 : 0000000c syscall error epc is ffffffff80000180,which is the address of except_vec3_generic. extcode in cause is 2 , which indicate a TLB load exception 2) cpu15 nmi trigger! dump... current running task:init on cpu15 epc : ffffffffc1077418 cmpxchg_futex_value_locked+0x88/0xc8 ra : ffffffffc10773b0 cmpxchg_futex_value_locked+0x20/0xc8 Status: 5448ffe7 KX SX UX KERNEL ERL EXL IE Cause : 40009008 BadVA : 000001b800000000 !!!!!!!!!!!!!!!ErroEPC : ffffffff80000184 Call Trace: [<ffffffffc1077418>] cmpxchg_futex_value_locked+0x88/0xc8 [<ffffffffc1718790>] futex_init+0x18/0x90 [<ffffffffc100c908>] do_one_initcall+0x38/0x190 [<ffffffffc1710b64>] kernel_init+0x1ec/0x26c [<ffffffffc101c510>] kernel_thread_helper+0x10/0x18 epc ffffffffc1077418: c2020000 ll v0,0(s0) error epc is ffffffff80000184,which is the second instruction in except_vec3_generic. extcode in cause is 2 , which also indicate a TLB load exception cpu ebase is set with 0xffffffff80000000. I guess this exception is caused by invalid setting of tlb or cache initialization, but can't find exactly where the problem is. Can you give some suggestion on how to figure it out? thanks in advance.
