Using printk in tracepoint causes the system to freeze

I am learning tracepoint related knowledge of Linux, and I wrote a module, as shown below.

#include <linux/module.h>#include <linux/kernel.h>#include <linux/init.h>#include <linux/moduleparam.h>#include <linux/unistd.h>#include <linux/sched.h>#include <linux/tracepoint.h>#define MAXNUM 600MODULE_LICENSE("GPL");static int monitored_pid = 0;module_param(monitored_pid, int, 0);MODULE_PARM_DESC(monitored_pid, "The pid of the monitored process.");void lookup_tps(struct tracepoint *tp, void *priv);void sys_enter_probe(struct pt_regs *regs, long id);static struct tracepoint * sys_enter_tp = NULL;static unsigned monitored_syscalls[MAXNUM];static int count = 0;int __init start(void){    int i = 0;    // find sys_enter tracepoint    for_each_kernel_tracepoint(lookup_tps, NULL);    if(sys_enter_tp == NULL){        printk(KERN_INFO "cannot find sys_enter tracepoint.\n");        // let module loading fail        return -1;    }    if(tracepoint_probe_register(sys_enter_tp, sys_enter_probe, NULL) != 0){        printk(KERN_INFO "regist fail.\n");        return -1;    }    for(i=0; i<MAXNUM; i++){        monitored_syscalls[i] = 0;    }    monitored_syscalls[__NR_open] = 1; // I want to monitor open operation    monitored_syscalls[__NR_openat] = 1;    printk(KERN_INFO "Start to monitor process of pid : %d\n", monitored_pid);    return 0;}void __exit end(void){    tracepoint_probe_unregister(sys_enter_tp, sys_enter_probe, NULL);    printk(KERN_INFO "End to monitor process of pid : %d\n", monitored_pid);    printk(KERN_INFO "open count : %d\n", count);}void lookup_tps(struct tracepoint *tp, void *priv){    if(strcmp(tp->name, "sys_enter") == 0){        sys_enter_tp = tp;    }}void sys_enter_probe(struct pt_regs *regs, long id){    if(id>=MAXNUM){        return;    }    if(monitored_syscalls[id] == 0){        return;    }    if(current->pid != monitored_pid){        return;    }    printk(KERN_INFO "1234\n");    count++;}module_init(start);module_exit(end);

When I entered the insmod command on the command line and pressed Enter, the system did not respond. After many experiments, I found that this problem occurs when writing count or using printk in the probe function(sys_enter_probe). I don't know much about the various mechanisms in the kernel, and I hope someone can tell me what rules my code violates and where I can learn these rules.