重复insmod 一个ko模块导致的异常问题解决方法

第一次insmod ko驱动，正常运行无异常，rmmod 后再insmod一次，就出现下面的异常，并且导致内核重启之后ko 也没法正常运行起来了，why？

<4>[  371.040525] ------------[ cut here ]------------

<4>[  371.040558] WARNING: at fs/sysfs/dir.c:455 sysfs_add_one+0x8c/0xc0()
<4>[  371.040580] sysfs: cannot create duplicate filename '/board_properties'
<4>[  371.040623] [<c04433a4>] (unwind_backtrace+0x0/0xf8) from [<c047416c>] (warn_slowpath_common+0x4c/0x64)
<4>[  371.040662] [<c047416c>] (warn_slowpath_common+0x4c/0x64) from [<c0474218>] (warn_slowpath_fmt+0x30/0x40)
<4>[  371.040699] [<c0474218>] (warn_slowpath_fmt+0x30/0x40) from [<c05642f4>] (sysfs_add_one+0x8c/0xc0)
<4>[  371.040739] [<c05642f4>] (sysfs_add_one+0x8c/0xc0) from [<c0564388>] (create_dir+0x60/0xbc)
<4>[  371.040773] [<c0564388>] (create_dir+0x60/0xbc) from [<c0564494>] (sysfs_create_dir+0x84/0xf0)
<4>[  371.040809] [<c0564494>] (sysfs_create_dir+0x84/0xf0) from [<c0611e00>] (kobject_add_internal+0x9c/0x1f4)
<4>[  371.040847] [<c0611e00>] (kobject_add_internal+0x9c/0x1f4) from [<c0612224>] (kobject_add+0x4c/0x94)
<4>[  371.040886] [<c0612224>] (kobject_add+0x4c/0x94) from [<c061240c>] (kobject_create_and_add+0x28/0x64)
<4>[  371.040931] [<c061240c>] (kobject_create_and_add+0x28/0x64) from [<bf052404>] (goodix_ts_init+0x14/0xe0 [gt9xx])
<4>[  371.040982] [<bf052404>] (goodix_ts_init+0x14/0xe0 [gt9xx]) from [<c04386f8>] (do_one_initcall+0xfc/0x164)
<4>[  371.041028] [<c04386f8>] (do_one_initcall+0xfc/0x164) from [<c04a9fc8>] (sys_init_module+0xcd0/0x1a68)
<4>[  371.041068] [<c04a9fc8>] (sys_init_module+0xcd0/0x1a68) from [<c043dfc0>] (ret_fast_syscall+0x0/0x30)
<4>[  371.041100] ---[ end trace 6dc940aed50f2806 ]---
<3>[  371.041126] kobject_add_internal failed for board_properties with -EEXIST, don't try to register things with the same name in the same directory.
<4>[  371.041175] [<c04433a4>] (unwind_backtrace+0x0/0xf8) from [<c0611f40>] (kobject_add_internal+0x1dc/0x1f4)
<4>[  371.041212] [<c0611f40>] (kobject_add_internal+0x1dc/0x1f4) from [<c0612224>] (kobject_add+0x4c/0x94)
<4>[  371.041294] [<c0612224>] (kobject_add+0x4c/0x94) from [<c061240c>] (kobject_create_and_add+0x28/0x64)
<4>[  371.041337] [<c061240c>] (kobject_create_and_add+0x28/0x64) from [<bf052404>] (goodix_ts_init+0x14/0xe0 [gt9xx])
<4>[  371.041388] [<bf052404>] (goodix_ts_init+0x14/0xe0 [gt9xx]) from [<c04386f8>] (do_one_initcall+0xfc/0x164)
<4>[  371.041428] [<c04386f8>] (do_one_initcall+0xfc/0x164) from [<c04a9fc8>] (sys_init_module+0xcd0/0x1a68)
<4>[  371.041466] [<c04a9fc8>] (sys_init_module+0xcd0/0x1a68) from [<c043dfc0>] (ret_fast_syscall+0x0/0x30)
<4>[  371.041500] kobject_create_and_add: kobject_add error: -17

<3>[  371.041521] failed to create board_properties

问题找到了！这个应该是卸载时候没有删除一些东西造成的，board_properties重复了，并且sysfs: cannot create duplicate filename '/board_properties'这提示太明显了，原来是我在exit 函数没有卸载掉kobject_create_and_add 产生的kobject，在exit 函数加入kobject_put完美解决这个问题，不过触摸虚拟按键还是不能用，咋回事呢？是不是权限问题呢，然后把ko文件由0777 改成0644 ，重启后，居然虚拟按键也好了！哦哦哦，太爽了，最大的障碍解决了！

参考下面的代码解决了。

static struct kobject *example_kobj;

static int __init example_init(void)
{
 int retval;

 /*
  * Create a simple kobject with the name of "kobject_example",
  * located under /sys/kernel/
  *
  * As this is a simple directory, no uevent will be sent to
  * userspace.  That is why this function should not be used for
  * any type of dynamic kobjects, where the name and number are
  * not known ahead of time.
  */
 example_kobj = kobject_create_and_add("kobject_example", kernel_kobj);
 if (!example_kobj)
  return -ENOMEM;

 /* Create the files associated with this kobject */
 retval = sysfs_create_group(example_kobj, &attr_group);
 if (retval)
  kobject_put(example_kobj);

 return retval;
}

static void __exit example_exit(void)
{
 kobject_put(example_kobj);
}