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");