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");
346
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