Question

In my own kernel module, I am trying to init a kthread within an interrupt handler function.

in the global scope I have:

static struct task_struct *thread1;

the function handler of the irq is:

static irqreturn_t* func_irq_handler (int irq, void *dev_id)
{   
    printk("irq handler ... \n");
    thread1 = kthread_create(thread_function,NULL,"my_thread");
    if ((thread1)) {
        printk(KERN_INFO "%s\n" , __FUNCTION__);
    }
    return IRQ_HANDLED;
}

and the thread function is:

static thread_function(void)
{
    unsigned long j1=jiffies+20000;
    int delay = 60*HZ;
    printk("%s \n",__FUNCTION__);

    while (time_before(jiffies,j1)) {
        schedule();
        printk(KERN_INFO "after schedule\n");
    }
}

the request_irq looks like this:

request_irq(irq,func_irq_handler,IRQF_TRIGGER_HIGH | IRQF_TRIGGER_RISING ,"test_irq",(void*)&my_miscdev);

why do I get this error:

BUG: scheduling while atomic: swapper

Answer 1

I would imagine that creating a thread requires interaction with the thread scheduler, which is not allowed at interrupt/atomic context.

A better approach would be to create your kernel thread elsewhere, and queue interrupt request processing to it.