Unable to handle kernel paging request at kthread_should_stop Hello, In a kernel module which used to work on previous kernel versions I tried to start a kernel thread (kthread). In the threads mainloop I poll the method kthread_should_stop which seems to fail. [ 65.531778] BUG: unable to handle kernel paging request at fffffffc [ 65.532011] IP: [<c103bf7c>] kthread_should_stop+0x10/0x14 [ 65.532011] *pde = 01551067 *pte = 00000000 [ 65.532011] Oops: 0000 [#1] SMP [ 65.532011] last sysfs file: /sys/devices/virtual/dmi/id/board_asset_tag [ 65.532011] Modules linked in: testmod [last unloaded: scsi_wait_scan] [ 65.532011] [ 65.532011] Pid: 3392, comm: test-module Not tainted 2.6.33.2-rt13 #1 E243/ E243 [ 65.532011] EIP: 0060:[<c103bf7c>] EFLAGS: 00010206 CPU: 0 [ 65.532011] EIP is at kthread_should_stop+0x10/0x14 [ 65.532011] EAX: 00000000 EBX: dd9e8430 ECX: 00006161 EDX: 00000286 [ 65.532011] ESI: 00000000 EDI: e00d8000 EBP: dc8e1fbc ESP: dc8e1fb0 [ 65.532011] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 preempt:00000000 [ 65.532011] Process test-module (pid: 3392, ti=dc8e0000 task=dd9e8430 task.ti=dc8e0000) [ 65.535828] Stack: [ 65.535828] e00d808c 00000000 d3945f50 dc8e1fe4 c103bfe1 00000000 00000001 00000101 [ 65.535828] <0> dc8e1fd0 dc8e1fd0 00000000 c103bf80 d3945f44 00000000 c1002e36 00000000 [ 65.535828] <0> 00000000 00000000 00000000 00000000 [ 65.535828] Call Trace: [ 65.535828] [<e00d808c>] ? runloop+0x8c/0xa4 [testmod] [ 65.535828] [<c103bfe1>] ? kthread+0x61/0x66 [ 65.535828] [<c103bf80>] ? kthread+0x0/0x66 [ 65.535828] [<c1002e36>] ? kernel_thread_helper+0x6/0x10[ 65.535828] Code: 8b 47 18 01 46 10 8b 55 f0 8d 47 08 e8 b1 a9 32 00 8d 65 f4 5b 5e 5f 5d c3 90 90 55 64 a1 7c 34 54 c1 8b 80 8c 01 00 00 89 e5 5d <8b> 40 fc
c3 55 ba a4 f6 59 c1 89 e5 57 56 53 89 c3 83 ec 14 8b [ 65.535828] EIP: [<c103bf7c>] kthread_should_stop+0x10/0x14 SS:ESP 0068:dc8e1fb0 [ 65.535828] CR2: 00000000fffffffc [ 65.535828] ---[ end trace 6b0fc9b05d23e589 ]--- My platform is an Intel Atom CPU N270. # uname -a Linux systemmanager 2.6.33.2-rt13 #1 SMP Sat Apr 10 00:12:20 CEST 2010 i686 GNU/Linux I attached a test module to reproduce this bug. Does I miss something in my code or is there a bug? Thanks for any help -- Stefan Agner ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/hrtimer.h>
#define THREAD_PRIORITY (80)
#define THREAD_SCHEDULER SCHED_FIFO
#define MODULE_NAME "test-module"
#define KLOG_PREFIX MODULE_NAME ": "
struct task_struct *thread;
static ktime_t thread_next;
static ktime_t now;
/*
* Threaded Runloop
*/
static int runloop(void *unused)
{
int ret;
/* Daemonize */
daemonize(MODULE_NAME);
/* Allow SIGTERM signal */
allow_signal(SIGTERM);
/* Calculate first shot */
now = ktime_get();
thread_next = ktime_add_us(now, 500);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
ret = schedule_hrtimeout(&thread_next, HRTIMER_MODE_ABS);
if(ret == -EINTR)
{
printk(KERN_INFO KLOG_PREFIX "Signal received\n");
continue;
}
thread_next = ktime_add_us(thread_next, 500);
} while (!kthread_should_stop());
printk(KERN_INFO KLOG_PREFIX "Thread exited\n");
return 0;
}
int __init init_test_module(void)
{
struct sched_param param = { .sched_priority = THREAD_PRIORITY };
/* Kernel Thread erzeugen */
if(thread == NULL)
thread = kthread_create((void *)&runloop, NULL, "testthread");
// Realtime scheduler
sched_setscheduler(thread, THREAD_SCHEDULER, ¶m);
wake_up_process(thread);
return 0;
}
void __exit cleanup_test_module(void)
{
if(thread != NULL)
kthread_stop(thread);
thread = NULL;
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Stefan Agner <stefan@xxxxxxxx");
MODULE_DESCRIPTION("kthread test module");
module_init(init_test_module);
module_exit(cleanup_test_module);
Attachment:
Makefile
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Attachment:
.config
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