Hi All, I have a requirement in printing irq stack usage information for each cpu. I am using the following: Linux Kernel: 4.9.x Board: hikey620 (arm64, armv8 with 8 cores) Platform: Ubuntu 14 debian As a vague idea, I tried to implement like this: ------------------------------------------------------------- static int dump_irq_stack_info(void) { int cpu, actual; unsigned long irq_stack_ptr; //unsigned long sp, sp1; unsigned long stack_start; unsigned long used; actual = IRQ_STACK_SIZE; used = 0; pr_info("CPU UNUSED-STACK ACTUAL-STACK\n"); //seq_printf(m, "CPU UNUSED-STACK ACTUAL-STACK\n"); for_each_present_cpu(cpu) { irq_stack_ptr = IRQ_STACK_PTR(cpu); //sp1 = current_stack_pointer; //sp = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr); stack_start = (unsigned long)per_cpu(irq_stack, cpu); used = irq_stack_ptr - stack_start; pr_info("%2d %10lu %10d\n", cpu, used, actual); //seq_printf(m, "%2d %10lu %10d\n", cpu, used, actual); } return 0; } ------------------------------------------------------------- Currently, when I tested this (as a proc interface), I got the below output: CPU UNUSED-STACK ACTUAL-STACK 0 16368 16384 1 16368 16384 2 16368 16384 3 16368 16384 4 16368 16384 5 16368 16384 6 16368 16384 7 16368 16384 ------------------------------------------------------------- But, I have some doubts: 1) I am not sure if my implementation is in right direction, or the logic is totally wrong. 2) Is there better way to perform the similar objective? 3) How should I test it to get the different usage values for unused stack ? Can I get these values by implementing a sample interrupt handler, and printing information from there? If this works, then I want to use it as part of dump_backtrace() function. If anybody have done a similar thing in past, or have some ideas to share, please help me. Note: This is required only for our internal debugging purpose. Regards, Pintu