[Crash-utility] bt command does not show stack traces of some CPUs.

Hi, I found a problem on crash-4.0-2.12. Summary: bt command does not show stack traces of some CPUs. Condition: This problem happens only on ia64 machine. There are two conditions to reproduce this problem. 1) Diskdump is executed via OS_INIT. 2) The machine has more than 8 CPUs. Details: When I executed bt command for vmcore which was created on the 32 CPU machine, bt didn't show stack traces of some CPU. Please see attached file(bt_failed.txt). Stack traces from CPU0 to CPU7 are showed normally, but stack traces from CPU8 to CPU31 are not. (Please don't worry about a message "unwind: bsp (xxxxxxxxx) out of range". This is a problem of our platform.) Cause: I found a bug in ia64.c. 2679 ms->ia64_init_stack_size = get_array_length("ia64_init_stack", 2680 NULL, 0); get_array_length() gets the length of stack of OS_INIT, and the length is stored at ms->ia64_init_stack_size. However, the value which get_array_length gives is different from actual stack length because "ia64_init_stack" is declared like this: u64 ia64_init_stack[NR_CPUS*KERNEL_STACK_SIZE/8]; Therefore, correct length of a stack is this: get_array_length("ia64_init_stack", NULL, 0) * sizeof(u64) I don't know how to fix, but it seems that attached patch (ia64.c.patch) corrects this problem. Another attached patch(test.patch) also seems to fix the problem, but I don't know which is better. Regards, Takao Indoh