NULL noise: drivers/misc
[linux-2.6.git] / drivers / misc / lkdtm.c
1 /*
2  * Kprobe module for testing crash dumps
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17  *
18  * Copyright (C) IBM Corporation, 2006
19  *
20  * Author: Ankita Garg <ankita@in.ibm.com>
21  *
22  * This module induces system failures at predefined crashpoints to
23  * evaluate the reliability of crash dumps obtained using different dumping
24  * solutions.
25  *
26  * It is adapted from the Linux Kernel Dump Test Tool by
27  * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
28  *
29  * Usage :  insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<>
30  *                                                      [cpoint_count={>0}]
31  *
32  * recur_count : Recursion level for the stack overflow test. Default is 10.
33  *
34  * cpoint_name : Crash point where the kernel is to be crashed. It can be
35  *               one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY,
36  *               FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD,
37  *               IDE_CORE_CP
38  *
39  * cpoint_type : Indicates the action to be taken on hitting the crash point.
40  *               It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW
41  *
42  * cpoint_count : Indicates the number of times the crash point is to be hit
43  *                to trigger an action. The default is 10.
44  */
45
46 #include <linux/kernel.h>
47 #include <linux/fs.h>
48 #include <linux/module.h>
49 #include <linux/buffer_head.h>
50 #include <linux/kprobes.h>
51 #include <linux/list.h>
52 #include <linux/init.h>
53 #include <linux/interrupt.h>
54 #include <linux/hrtimer.h>
55 #include <scsi/scsi_cmnd.h>
56
57 #ifdef CONFIG_IDE
58 #include <linux/ide.h>
59 #endif
60
61 #define NUM_CPOINTS 8
62 #define NUM_CPOINT_TYPES 5
63 #define DEFAULT_COUNT 10
64 #define REC_NUM_DEFAULT 10
65
66 enum cname {
67         INVALID,
68         INT_HARDWARE_ENTRY,
69         INT_HW_IRQ_EN,
70         INT_TASKLET_ENTRY,
71         FS_DEVRW,
72         MEM_SWAPOUT,
73         TIMERADD,
74         SCSI_DISPATCH_CMD,
75         IDE_CORE_CP
76 };
77
78 enum ctype {
79         NONE,
80         PANIC,
81         BUG,
82         EXCEPTION,
83         LOOP,
84         OVERFLOW
85 };
86
87 static char* cp_name[] = {
88         "INT_HARDWARE_ENTRY",
89         "INT_HW_IRQ_EN",
90         "INT_TASKLET_ENTRY",
91         "FS_DEVRW",
92         "MEM_SWAPOUT",
93         "TIMERADD",
94         "SCSI_DISPATCH_CMD",
95         "IDE_CORE_CP"
96 };
97
98 static char* cp_type[] = {
99         "PANIC",
100         "BUG",
101         "EXCEPTION",
102         "LOOP",
103         "OVERFLOW"
104 };
105
106 static struct jprobe lkdtm;
107
108 static int lkdtm_parse_commandline(void);
109 static void lkdtm_handler(void);
110
111 static char* cpoint_name;
112 static char* cpoint_type;
113 static int cpoint_count = DEFAULT_COUNT;
114 static int recur_count = REC_NUM_DEFAULT;
115
116 static enum cname cpoint = INVALID;
117 static enum ctype cptype = NONE;
118 static int count = DEFAULT_COUNT;
119
120 module_param(recur_count, int, 0644);
121 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test, "\
122                                  "default is 10");
123 module_param(cpoint_name, charp, 0644);
124 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
125 module_param(cpoint_type, charp, 0644);
126 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
127                                 "hitting the crash point");
128 module_param(cpoint_count, int, 0644);
129 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
130                                 "crash point is to be hit to trigger action");
131
132 static unsigned int jp_do_irq(unsigned int irq)
133 {
134         lkdtm_handler();
135         jprobe_return();
136         return 0;
137 }
138
139 static irqreturn_t jp_handle_irq_event(unsigned int irq,
140                                        struct irqaction *action)
141 {
142         lkdtm_handler();
143         jprobe_return();
144         return 0;
145 }
146
147 static void jp_tasklet_action(struct softirq_action *a)
148 {
149         lkdtm_handler();
150         jprobe_return();
151 }
152
153 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
154 {
155         lkdtm_handler();
156         jprobe_return();
157 }
158
159 struct scan_control;
160
161 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
162                                              struct zone *zone,
163                                              struct scan_control *sc)
164 {
165         lkdtm_handler();
166         jprobe_return();
167         return 0;
168 }
169
170 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
171                             const enum hrtimer_mode mode)
172 {
173         lkdtm_handler();
174         jprobe_return();
175         return 0;
176 }
177
178 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
179 {
180         lkdtm_handler();
181         jprobe_return();
182         return 0;
183 }
184
185 #ifdef CONFIG_IDE
186 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
187                         struct block_device *bdev, unsigned int cmd,
188                         unsigned long arg)
189 {
190         lkdtm_handler();
191         jprobe_return();
192         return 0;
193 }
194 #endif
195
196 static int lkdtm_parse_commandline(void)
197 {
198         int i;
199
200         if (cpoint_name == NULL || cpoint_type == NULL ||
201                                         cpoint_count < 1 || recur_count < 1)
202                 return -EINVAL;
203
204         for (i = 0; i < NUM_CPOINTS; ++i) {
205                 if (!strcmp(cpoint_name, cp_name[i])) {
206                         cpoint = i + 1;
207                         break;
208                 }
209         }
210
211         for (i = 0; i < NUM_CPOINT_TYPES; ++i) {
212                 if (!strcmp(cpoint_type, cp_type[i])) {
213                         cptype = i + 1;
214                         break;
215                 }
216         }
217
218         if (cpoint == INVALID || cptype == NONE)
219                 return -EINVAL;
220
221         count = cpoint_count;
222
223         return 0;
224 }
225
226 static int recursive_loop(int a)
227 {
228         char buf[1024];
229
230         memset(buf,0xFF,1024);
231         recur_count--;
232         if (!recur_count)
233                 return 0;
234         else
235                 return recursive_loop(a);
236 }
237
238 void lkdtm_handler(void)
239 {
240         printk(KERN_INFO "lkdtm : Crash point %s of type %s hit\n",
241                                          cpoint_name, cpoint_type);
242         --count;
243
244         if (count == 0) {
245                 switch (cptype) {
246                 case NONE:
247                         break;
248                 case PANIC:
249                         printk(KERN_INFO "lkdtm : PANIC\n");
250                         panic("dumptest");
251                         break;
252                 case BUG:
253                         printk(KERN_INFO "lkdtm : BUG\n");
254                         BUG();
255                         break;
256                 case EXCEPTION:
257                         printk(KERN_INFO "lkdtm : EXCEPTION\n");
258                         *((int *) 0) = 0;
259                         break;
260                 case LOOP:
261                         printk(KERN_INFO "lkdtm : LOOP\n");
262                         for (;;);
263                         break;
264                 case OVERFLOW:
265                         printk(KERN_INFO "lkdtm : OVERFLOW\n");
266                         (void) recursive_loop(0);
267                         break;
268                 default:
269                         break;
270                 }
271                 count = cpoint_count;
272         }
273 }
274
275 static int __init lkdtm_module_init(void)
276 {
277         int ret;
278
279         if (lkdtm_parse_commandline() == -EINVAL) {
280                 printk(KERN_INFO "lkdtm : Invalid command\n");
281                 return -EINVAL;
282         }
283
284         switch (cpoint) {
285         case INT_HARDWARE_ENTRY:
286                 lkdtm.kp.symbol_name = "__do_IRQ";
287                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
288                 break;
289         case INT_HW_IRQ_EN:
290                 lkdtm.kp.symbol_name = "handle_IRQ_event";
291                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
292                 break;
293         case INT_TASKLET_ENTRY:
294                 lkdtm.kp.symbol_name = "tasklet_action";
295                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
296                 break;
297         case FS_DEVRW:
298                 lkdtm.kp.symbol_name = "ll_rw_block";
299                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
300                 break;
301         case MEM_SWAPOUT:
302                 lkdtm.kp.symbol_name = "shrink_inactive_list";
303                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
304                 break;
305         case TIMERADD:
306                 lkdtm.kp.symbol_name = "hrtimer_start";
307                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
308                 break;
309         case SCSI_DISPATCH_CMD:
310                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
311                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
312                 break;
313         case IDE_CORE_CP:
314 #ifdef CONFIG_IDE
315                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
316                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
317 #else
318                 printk(KERN_INFO "lkdtm : Crash point not available\n");
319 #endif
320                 break;
321         default:
322                 printk(KERN_INFO "lkdtm : Invalid Crash Point\n");
323                 break;
324         }
325
326         if ((ret = register_jprobe(&lkdtm)) < 0) {
327                 printk(KERN_INFO "lkdtm : Couldn't register jprobe\n");
328                 return ret;
329         }
330
331         printk(KERN_INFO "lkdtm : Crash point %s of type %s registered\n",
332                                                 cpoint_name, cpoint_type);
333         return 0;
334 }
335
336 static void __exit lkdtm_module_exit(void)
337 {
338         unregister_jprobe(&lkdtm);
339         printk(KERN_INFO "lkdtm : Crash point unregistered\n");
340 }
341
342 module_init(lkdtm_module_init);
343 module_exit(lkdtm_module_exit);
344
345 MODULE_LICENSE("GPL");