如果我们睡在SMP机器上的中断处理器中会发生什么,
keyboard driver
并在中断处理程序上添加了睡眠
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/sched/signal.h>
MODULE_LICENSE("GPL");
static int irq = 1, dev = 0xaa, counter = 0;
static irqreturn_t keyboard_handler(int irq, void *dev)
{
pr_info("Keyboard Counter:%d\n", counter++);
msleep(1000);
return IRQ_NONE;
}
/* registering irq */
static int test_interrupt_init(void)
{
pr_info("%s: In init\n", __func__);
return request_irq(irq, keyboard_handler, IRQF_SHARED,"my_keyboard_handler", &dev);
}
static void test_interrupt_exit(void)
{
pr_info("%s: In exit\n", __func__);
synchronize_irq(irq); /* synchronize interrupt */
free_irq(irq, &dev);
}
module_init(test_interrupt_init);
module_exit(test_interrupt_exit);
系统运行了几分钟,然后出现了死机。为什么系统不能在禁用一个处理器的情况下工作,因为计时器中断将在另一个CPU上触发,并且可以调度进程。
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1254]
0x0000000000000000 in irq_stack_union ()
(gdb) bt
#0 0x0000000000000000 in irq_stack_union ()
#1 0xffffffff810ad8e4 in ttwu_activate (en_flags=<optimized out>, p=<optimized out>, rq=<optimized out>)
at kernel/sched/core.c:1638
#2 ttwu_do_activate (rq=0xffff888237422c40, p=0xffffffff82213780 <init_task>, wake_flags=9,
rf=0xffffc900022b3f10) at kernel/sched/core.c:1697
#3 0xffffffff810aec00 in sched_ttwu_pending () at kernel/sched/core.c:1740
#4 0xffffffff810aedcd in scheduler_ipi () at kernel/sched/core.c:1771
#5 0xffffffff81a01aef in reschedule_interrupt () at arch/x86/entry/entry_64.S:888
#6 0xffffc900022b3f58 in ?? ()
#7 0xffffffff81a01aea in reschedule_interrupt () at arch/x86/entry/entry_64.S:888
#8 0x0000000000000002 in irq_stack_union ()
#9 0x00007fcec3421b40 in ?? ()
#10 0x0000000000000006 in irq_stack_union ()
#11 0x00007fceb00008c0 in ?? ()
#12 0x0000000000000002 in irq_stack_union ()
#13 0x00000000020bd380 in ?? ()
#14 0x0012c8d2cc413914 in ?? ()
Cannot access memory at address 0x5000
