作者:
2013-01-16 12:29:35
有一个模块叫GCI.ko，它export出来三个GCIReg、GCIStatNew、GCICtlNew函数
原型分别是
GCIHandle *GCIReg(char *moduleName)
GCICtlHandle *GCICtlNew(GCIHandle *moduleHandle, char *ctlFileName, GCICtlCmd *cmdTable, void *privData)
GCIStatHandle *GCIStatNew(GCIHandle *moduleHandle, char *statFileName, GCIStatDesc *descTable)
现在在Ipdb模块里调用它们
首先声明模块参数
26 static char *mod_name = "IPDB";
27 static char *ctl_file_name = "Control";
28 static char *stat_file_name = "Stat";
29 static void * cm_get_net_entity = CMGetNetEntity;
1598 module_param(mod_name, charp, S_IRUGO);
1599 module_param(ctl_file_name, charp, S_IRUGO);
1600 module_param(stat_file_name, charp, S_IRUGO);
1601 module_param(cm_get_net_entity, charp, S_IRUGO);
module_init(IPDB_init_module) 里的代码片段
106 GuardNotify(mod_name, GUARD_LOG_ERROR, NOPKT,
107 "before GCIReg (0x%x:%s)\n",
108 mod_name, mod_name);
109 GCI_h = GCIReg(mod_name);
：
116
117 GuardNotify(mod_name, GUARD_LOG_ERROR, NOPKT,
118 "before GCICtlNew (0x%x: %s) %s \n",
119 ctl_file_name, ctl_file_name, mod_name);
120 GCI_Ctl_h = GCICtlNew(GCI_h, ctl_file_name, cmds, NULL);
：
122 GuardNotify(mod_name, GUARD_LOG_ERROR, NOPKT,
123 "before GCIStatNew (0x%x: %s) %s\n",
124 stat_file_name, stat_file_name, mod_name);
125 GCI_Stat_h = GCIStatNew(GCI_h, stat_file_name, statDesc) ;
insmod时，模块被kill，dmesg打印出来的信息如下：
[ 350.756636] <1>GUARD ERR IPDB PKT ffffffff: before GCIReg (0xf7ffb924:IPDB)
[ 350.756641] <1>GUARD ERR GCI PKT ffffffff: registering GCIReg (0xf7ffb924:IPDB)
[ 350.756651] <1>GUARD ERR IPDB PKT ffffffff: before GCICtlNew (0xf7ffb929: Control) IPDB
[ 350.756654] <1>GUARD DBG GCI PKT ffffffff: creating ctl file (0xf7ffb929: Control) for module IPDB
[ 350.756657] <1>GUARD ERR IPDB PKT ffffffff: before GCIStatNew (0xf7ffb973: Stat) IPDB
[ 350.756660] <1>GUARD DBG GCI PKT ffffffff: creating stat file (0x46: (null)) for module IPDB
[ 350.756670] BUG: unable to handle kernel NULL pointer dereference at 00000046
如果把GCIStatNew挪到GCICtlNew前边调用，insmod时，模块被kill，dmesg打印出来的信息如下：
[ 170.913746] <1>GUARD ERR IPDB PKT ffffffff: before GCIReg (0xf807b924:IPDB)
[ 170.913751] <1>GUARD ERR GCI PKT ffffffff: registering GCIReg (0xf807b924:IPDB)
[ 170.913757] <1>GUARD ERR IPDB PKT ffffffff: before GCIStatNew (0xf807b929: Stat) IPDB
[ 170.913760] <1>GUARD DBG GCI PKT ffffffff: creating stat file (0xf807b929: Stat) for module IPDB
[ 170.913764] <1>GUARD ERR IPDB PKT ffffffff: before GCICtlNew (0xf807b947: Control) IPDB
[ 170.913767] <1>GUARD DBG GCI PKT ffffffff: creating ctl file (0x46: (null)) for module IPDB
[ 170.913776] BUG: unable to handle kernel NULL pointer dereference at 00000046
就是说传入前两个参数都是对的，传入第三个参数时，传入为空，传进去后它地址就变成0x46:
上网查，说是一个模块能传入30个参数，有的人说能传入70个参数，我这个问题是只能传两个参数
同样的我在insmod 时自己填参数也是这个问题
代码中直接传字符串也是这个问题。
请大侠帮忙看看啊，很诡异的问题啊。谢谢谢谢！