SIGKILL and a sleeping kernel module

Kevin Wilson wkevils at gmail.com
Tue Feb 19 03:37:28 EST 2013


Hi all,
I am trying to send a SIGKILL to a kernel module which is sleeping.
I added a printk after the sleep command.
Sending a SIGLKILL (by kill -9 SIGLKILL pidOfKernelThread) does **not**
yield the message from printk("calling do_exit\n");
 which is immediately after the msleep() command, as I expected.

Moreover, ps before and after the kill show 'D' in the STAT column
(STATUS), which means that the process is sleeping (If I am not
wrong).

Any ideas why ?
below is the code:

#include<linux/init.h>
#include<linux/module.h>
#include<linux/kernel.h>
#include<linux/kthread.h>
#include<linux/sched.h>
#include <linux/delay.h>

struct task_struct *task;

int thread_function(void *data)
{
    int exit_sig = SIGKILL;

    allow_signal(SIGKILL);

    printk("in %s\n",__func__);
    // sleep for a second
    msleep(60000);
    printk("calling do_exit\n");
    do_exit(exit_sig);

    return 0;
}

static int kernel_init(void)
    {
    task = kthread_create(thread_function,NULL,"MY_KERNEL_THREAD");
    return 0;
}

static void kernel_exit(void)
    {
    printk("in kernel_exit\n");
    kthread_stop(task);
    }


module_init(kernel_init);
module_exit(kernel_exit);

MODULE_AUTHOR("Tester");
MODULE_DESCRIPTION("test");
MODULE_LICENSE("GPL");

rgs,
Kevin



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