字符设备cdev_del冒出的调用流程

在我写linux驱动时候，是关于字符设备的，在卸载函数里，有这么一个调用：
printk(KERN_ALERT "the adl_dev is to del");
cdev_del(&adl_dev.pcdev); //remove the character device
printk(KERN_ALERT "the adl_dev is del");
卸载的时候，会调用此函数：然后在dmesg命令后，找到如下相关的东西！
这个是怎么回事呢？是我那有错？还是只是一个具体流程！为什么我的其他函数，就没有这个呢？
1934.879632] the adl_dev is to del
[ 1934.879663] ------------[ cut here ]------------
[ 1934.879673] WARNING: at lib/kobject.c:595 kobject_put+0x48/0x4d()
[ 1934.879676] Hardware name:
[ 1934.879679] kobject: '(null)' (e0046bdc): is not initialized, yet kobject_put() is being called.
[ 1934.879682] Modules linked in: adlink(-) intel_agp agpgart sg [last unloaded: adlink]
[ 1934.879691] Pid: 2769, comm: rmmod Not tainted 2.6.34.1 #1
[ 1934.879694] Call Trace:
[ 1934.879701] [] warn_slowpath_common+0x67/0x90
[ 1934.879706] [] ? kobject_put+0x48/0x4d
[ 1934.879710] [] ? kobject_put+0x48/0x4d
[ 1934.879715] [] warn_slowpath_fmt+0x26/0x28
[ 1934.879719] [] kobject_put+0x48/0x4d
[ 1934.879725] [] cdev_del+0x1d/0x20
[ 1934.879731] [] adl_remove+0x10/0x36 [adlink]
[ 1934.879738] [] pci_device_remove+0x19/0x3a
[ 1934.879745] [] __device_release_driver+0x3e/0x7d
[ 1934.879750] [] driver_detach+0x94/0xaf
[ 1934.879755] [] bus_remove_driver+0x5a/0x91
[ 1934.879760] [] driver_unregister+0x3d/0x67
[ 1934.879765] [] ? sysfs_remove_file+0xd/0xf
[ 1934.879770] [] pci_unregister_driver+0x2a/0x8a
[ 1934.879775] [] adl_exit_module+0x1c/0x1e [adlink]
[ 1934.879781] [] sys_delete_module+0x180/0x1d0
[ 1934.879787] [] ? do_munmap+0x1ed/0x2b3
[ 1934.879792] [] sysenter_do_call+0x12/0x22
[ 1934.879796] ---[ end trace d58467bd0e50a9cd ]---
[ 1934.879798] the adl_dev is to del