添加两个案例

README.md

@@ -96,6 +96,7 @@
     * [内核链表踩踏-前序节点](docs/案例/内核链表踩踏-前序节点.md)
     * [内核链表踩踏-后继节点](docs/案例/内核链表踩踏-后继节点.md)
     * [softlockup-等待状态寄存器](docs/案例/softlockup-等待状态寄存器.md)
+    * [softlockup-CPU无限循环](docs/案例/softlockup-CPU无限循环.md)
 
 
 

SUMMARY.md

@@ -86,4 +86,5 @@
     * [NULLPOINTER-空指针参数](docs/案例/NULLPOINTER-空指针参数.md)
     * [内核链表踩踏-前序节点](docs/案例/内核链表踩踏-前序节点.md)
     * [内核链表踩踏-后继节点](docs/案例/内核链表踩踏-后继节点.md)
-    * [softlockup-等待状态寄存器](docs/案例/softlockup-等待状态寄存器.md)
+    * [softlockup-等待状态寄存器](docs/案例/softlockup-等待状态寄存器.md)
+    * [softlockup-CPU无限循环](docs/案例/softlockup-CPU无限循环.md)

docs/案例/softlockup-CPU无限循环.md

@@ -0,0 +1,133 @@
+<!-- TOC -->
+
+- [内核模块触发softlockCPU无限循环异常](#内核模块触发softlockCPU无限循环异常)
+	- [代码](#代码)
+	- [堆栈](#堆栈)
+
+<!-- /TOC -->
+# 内核模块触发softlockCPU无限循环异常
+
+## 开启内核参数
+
+``` bash
+kernel.hardlockup_all_cpu_backtrace = 0
+kernel.hardlockup_panic = 0
+
+kernel.softlockup_all_cpu_backtrace = 1
+kernel.softlockup_panic = 1
+```
+
+## 代码
+
+``` c
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/cpumask.h>
+
+// 定义一个函数，在每个 CPU 上执行
+static void hello_from_cpu(void *data)
+{
+    int cpu = smp_processor_id();
+    printk(KERN_INFO "Hello from CPU %d\n", cpu);
+    while (1){};
+}
+
+// 模块初始化函数
+static int __init hello_init(void)
+{
+    printk(KERN_INFO "Loading Hello module...\n");
+
+    // 在所有 CPU 上执行 hello_from_cpu 函数
+    smp_call_function_many(cpu_online_mask, hello_from_cpu, NULL, true);
+
+    return 0;
+}
+
+// 模块退出函数
+static void __exit hello_exit(void)
+{
+    printk(KERN_INFO "Unloading Hello module...\n");
+}
+
+module_init(hello_init);
+module_exit(hello_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Your Name");
+MODULE_DESCRIPTION("A simple kernel module to print 'Hello from CPU X' on all CPUs");
+```
+
+## 堆栈
+
+
+``` bash
+GNU gdb (GDB) 7.6
+Copyright (C) 2013 Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
+and "show warranty" for details.
+This GDB was configured as "x86_64-unknown-linux-gnu"...
+
+WARNING: kernel relocated [52MB]: patching 82532 gdb minimal_symbol values
+
+      KERNEL: /lib/debug/lib/modules/3.10.0-862.el7.x86_64/vmlinux
+    DUMPFILE: vmcore  [PARTIAL DUMP]
+        CPUS: 4
+        DATE: Mon Oct 14 16:11:42 2024
+      UPTIME: 00:02:08
+LOAD AVERAGE: 1.98, 0.50, 0.17
+       TASKS: 317
+    NODENAME: centos7
+     RELEASE: 3.10.0-862.el7.x86_64
+     VERSION: #1 SMP Fri Apr 20 16:44:24 UTC 2018
+     MACHINE: x86_64  (2593 Mhz)
+      MEMORY: 16 GB
+       PANIC: "Kernel panic - not syncing: softlockup: hung tasks"
+         PID: 1899
+     COMMAND: "insmod"
+        TASK: ffff95545a28bf40  [THREAD_INFO: ffff9550f5420000]
+         CPU: 0
+       STATE: TASK_RUNNING (PANIC)
+
+crash> bt
+PID: 1899   TASK: ffff95545a28bf40  CPU: 0   COMMAND: "insmod"
+ #0 [ffff95546ce03d38] machine_kexec at ffffffff84460b2a
+ #1 [ffff95546ce03d98] __crash_kexec at ffffffff84513402
+ #2 [ffff95546ce03e68] panic at ffffffff84b07a75
+ #3 [ffff95546ce03ee8] watchdog_timer_fn at ffffffff8453f5f1
+ #4 [ffff95546ce03f20] __hrtimer_run_queues at ffffffff844beff6
+ #5 [ffff95546ce03f78] hrtimer_interrupt at ffffffff844bf58f
+ #6 [ffff95546ce03fc0] local_apic_timer_interrupt at ffffffff8445782b
+ #7 [ffff95546ce03fd8] smp_apic_timer_interrupt at ffffffff84b240a3
+ #8 [ffff95546ce03ff0] apic_timer_interrupt at ffffffff84b207f2
+--- <IRQ stack> ---
+ #9 [ffff9550f5423c88] apic_timer_interrupt at ffffffff84b207f2
+    [exception RIP: init_module+4]
+    RIP: ffffffffc00b8004  RSP: ffff9550f5423d30  RFLAGS: 00000246
+    RAX: ffff9550f616ac01  RBX: ffffffffc03ca018  RCX: 0000000000019bb2
+    RDX: 0000000000019bb1  RSI: 0000000000000000  RDI: ffff9551bfc07b00
+    RBP: ffff9550f5423d30   R8: 000000000001ba40   R9: ffffffff844020f8
+    R10: ffff95546ce1ba40  R11: ffffee3b02d85a80  R12: ffff9550f5423d00
+    R13: ffff9550f5423d40  R14: 0000000000000018  R15: ffffffff8475c7fa
+    ORIG_RAX: ffffffffffffff10  CS: 0010  SS: 0018
+#10 [ffff9550f5423d38] do_one_initcall at ffffffff8440210a
+#11 [ffff9550f5423d68] load_module at ffffffff8450f5ac
+#12 [ffff9550f5423eb8] sys_finit_module at ffffffff8450fbf6
+#13 [ffff9550f5423f50] system_call_fastpath at ffffffff84b1f7d5
+    RIP: 00007f73bfb5ee29  RSP: 00007ffe98c20e68  RFLAGS: 00010207
+    RAX: 0000000000000139  RBX: 0000000001dcc210  RCX: 00007f73bfbd0f90
+    RDX: 0000000000000000  RSI: 000000000041aa0e  RDI: 0000000000000003
+    RBP: 000000000041aa0e   R8: 0000000000000000   R9: 00007ffe98c21078
+    R10: 0000000000000003  R11: 0000000000000206  R12: 0000000000000000
+    R13: 0000000001dcc1d0  R14: 0000000000000000  R15: 0000000000000000
+    ORIG_RAX: 0000000000000139  CS: 0033  SS: 002b
+crash>
+```
+
+
+
+
+
+---

docs/案例/taskhung-内核线程死锁.md

@@ -0,0 +1,125 @@
+<!-- TOC -->
+
+- [内核模块触发空指针异常](#内核模块死锁异常)
+	- [代码](#代码)
+	- [堆栈](#堆栈)
+
+<!-- /TOC -->
+# 内核模块死锁异常
+
+## 开启内核参数
+
+``` bash
+# **`sysctl -w kernel.hung_task_panic=1`**
+kernel.hung_task_panic = 1
+kernel.hung_task_timeout_secs=60
+```
+
+``` bash
+sysctl -p
+```
+## 代码
+
+``` c
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/cpumask.h>
+
+static DEFINE_MUTEX(mutex1);
+static DEFINE_MUTEX(mutex2);
+
+// 定义一个函数，在每个 CPU 上执行
+static void deadlock_on_cpu(void *data)
+{
+    int cpu = smp_processor_id();
+    printk(KERN_INFO "Deadlock on CPU %d\n", cpu);
+
+    if (cpu % 2 == 0) {
+        mutex_lock(&mutex1);
+        msleep(100);  // 等待一段时间，确保另一个 CPU 获取 mutex2
+        mutex_lock(&mutex2);
+    } else {
+        mutex_lock(&mutex2);
+        msleep(100);  // 等待一段时间，确保另一个 CPU 获取 mutex1
+        mutex_lock(&mutex1);
+    }
+
+    // 永远不会到达这里
+    mutex_unlock(&mutex1);
+    mutex_unlock(&mutex2);
+}
+
+// 模块初始化函数
+static int __init deadlock_init(void)
+{
+    printk(KERN_INFO "Loading Deadlock module...\n");
+
+    // 在所有 CPU 上执行 deadlock_on_cpu 函数
+    smp_call_function_many(cpu_online_mask, deadlock_on_cpu, NULL, true);
+
+    return 0;
+}
+
+// 模块退出函数
+static void __exit deadlock_exit(void)
+{
+    printk(KERN_INFO "Unloading Deadlock module...\n");
+}
+
+module_init(deadlock_init);
+module_exit(deadlock_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Your Name");
+MODULE_DESCRIPTION("A simple kernel module to simulate a deadlock");
+```
+
+makefile
+``` c
+obj-m += lkm_hello_world.o
+
+all:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+
+clean:
+	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
+
+test:
+	sudo dmesg -C
+	sudo insmod lkm_hello_world.ko
+	sudo rmmod lkm_hello_world.ko
+	dmesg
+```
+
+``` bash
+[root@centos7 hello-world-linux-module]# ls
+Makefile  README.md  lkm_hello_world.c  lkm_hello_world.c.bak  screenshots
+[root@centos7 hello-world-linux-module]# make
+make -C /lib/modules/3.10.0-862.el7.x86_64/build M=/root/hello-world-linux-module modules
+make[1]: Entering directory `/usr/src/kernels/3.10.0-862.el7.centos.x86_64'
+  CC [M]  /root/hello-world-linux-module/lkm_hello_world.o
+  Building modules, stage 2.
+  MODPOST 1 modules
+  CC      /root/hello-world-linux-module/lkm_hello_world.mod.o
+  LD [M]  /root/hello-world-linux-module/lkm_hello_world.ko
+make[1]: Leaving directory `/usr/src/kernels/3.10.0-862.el7.centos.x86_64'
+```
+
+安装完ko之后，系统会hung死，并出发crash
+``` bash
+insmod lkm_hello_world.ko
+```
+
+## 堆栈
+
+![1](../image/WeChatWorkScreenshot_13889554-7cfa-4536-b945-efc6e3feddb2.png)
+
+
+
+
+
+---