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 unsigned int jp_do_irq(unsigned int irq)
 133 {
 134         lkdtm_handler();
 135         jprobe_return();
 136         return 0;
 137 }
 138
 139 irqreturn_t jp_handle_irq_event(unsigned int irq, struct irqaction *action)
 140 {
 141         lkdtm_handler();
 142         jprobe_return();
 143         return 0;
 144 }
 145
 146 void jp_tasklet_action(struct softirq_action *a)
 147 {
 148         lkdtm_handler();
 149         jprobe_return();
 150 }
 151
 152 void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 153 {
 154         lkdtm_handler();
 155         jprobe_return();
 156 }
 157
 158 struct scan_control;
 159
 160 unsigned long jp_shrink_inactive_list(unsigned long max_scan,
 161                                 struct zone *zone, struct scan_control *sc)
 162 {
 163         lkdtm_handler();
 164         jprobe_return();
 165         return 0;
 166 }
 167
 168 int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 169                                 const enum hrtimer_mode mode)
 170 {
 171         lkdtm_handler();
 172         jprobe_return();
 173         return 0;
 174 }
 175
 176 int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 177 {
 178         lkdtm_handler();
 179         jprobe_return();
 180         return 0;
 181 }
 182
 183 #ifdef CONFIG_IDE
 184 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 185                         struct block_device *bdev, unsigned int cmd,
 186                         unsigned long arg)
 187 {
 188         lkdtm_handler();
 189         jprobe_return();
 190         return 0;
 191 }
 192 #endif
 193
 194 static int lkdtm_parse_commandline(void)
 195 {
 196         int i;
 197
 198         if (cpoint_name == INVALID || cpoint_type == NONE ||
 199                                         cpoint_count < 1 || recur_count < 1)
 200                 return -EINVAL;
 201
 202         for (i = 0; i < NUM_CPOINTS; ++i) {
 203                 if (!strcmp(cpoint_name, cp_name[i])) {
 204                         cpoint = i + 1;
 205                         break;
 206                 }
 207         }
 208
 209         for (i = 0; i < NUM_CPOINT_TYPES; ++i) {
 210                 if (!strcmp(cpoint_type, cp_type[i])) {
 211                         cptype = i + 1;
 212                         break;
 213                 }
 214         }
 215
 216         if (cpoint == INVALID || cptype == NONE)
 217                 return -EINVAL;
 218
 219         count = cpoint_count;
 220
 221         return 0;
 222 }
 223
 224 static int recursive_loop(int a)
 225 {
 226         char buf[1024];
 227
 228         memset(buf,0xFF,1024);
 229         recur_count--;
 230         if (!recur_count)
 231                 return 0;
 232         else
 233                 return recursive_loop(a);
 234 }
 235
 236 void lkdtm_handler(void)
 237 {
 238         printk(KERN_INFO "lkdtm : Crash point %s of type %s hit\n",
 239                                          cpoint_name, cpoint_type);
 240         --count;
 241
 242         if (count == 0) {
 243                 switch (cptype) {
 244                 case NONE:
 245                         break;
 246                 case PANIC:
 247                         printk(KERN_INFO "lkdtm : PANIC\n");
 248                         panic("dumptest");
 249                         break;
 250                 case BUG:
 251                         printk(KERN_INFO "lkdtm : BUG\n");
 252                         BUG();
 253                         break;
 254                 case EXCEPTION:
 255                         printk(KERN_INFO "lkdtm : EXCEPTION\n");
 256                         *((int *) 0) = 0;
 257                         break;
 258                 case LOOP:
 259                         printk(KERN_INFO "lkdtm : LOOP\n");
 260                         for (;;);
 261                         break;
 262                 case OVERFLOW:
 263                         printk(KERN_INFO "lkdtm : OVERFLOW\n");
 264                         (void) recursive_loop(0);
 265                         break;
 266                 default:
 267                         break;
 268                 }
 269                 count = cpoint_count;
 270         }
 271 }
 272
 273 int lkdtm_module_init(void)
 274 {
 275         int ret;
 276
 277         if (lkdtm_parse_commandline() == -EINVAL) {
 278                 printk(KERN_INFO "lkdtm : Invalid command\n");
 279                 return -EINVAL;
 280         }
 281
 282         switch (cpoint) {
 283         case INT_HARDWARE_ENTRY:
 284                 lkdtm.kp.symbol_name = "__do_IRQ";
 285                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 286                 break;
 287         case INT_HW_IRQ_EN:
 288                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 289                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 290                 break;
 291         case INT_TASKLET_ENTRY:
 292                 lkdtm.kp.symbol_name = "tasklet_action";
 293                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 294                 break;
 295         case FS_DEVRW:
 296                 lkdtm.kp.symbol_name = "ll_rw_block";
 297                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 298                 break;
 299         case MEM_SWAPOUT:
 300                 lkdtm.kp.symbol_name = "shrink_inactive_list";
 301                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
 302                 break;
 303         case TIMERADD:
 304                 lkdtm.kp.symbol_name = "hrtimer_start";
 305                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 306                 break;
 307         case SCSI_DISPATCH_CMD:
 308                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 309                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 310                 break;
 311         case IDE_CORE_CP:
 312 #ifdef CONFIG_IDE
 313                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 314                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 315 #else
 316                 printk(KERN_INFO "lkdtm : Crash point not available\n");
 317 #endif
 318                 break;
 319         default:
 320                 printk(KERN_INFO "lkdtm : Invalid Crash Point\n");
 321                 break;
 322         }
 323
 324         if ((ret = register_jprobe(&lkdtm)) < 0) {
 325                 printk(KERN_INFO "lkdtm : Couldn't register jprobe\n");
 326                 return ret;
 327         }
 328
 329         printk(KERN_INFO "lkdtm : Crash point %s of type %s registered\n",
 330                                                 cpoint_name, cpoint_type);
 331         return 0;
 332 }
 333
 334 void lkdtm_module_exit(void)
 335 {
 336         unregister_jprobe(&lkdtm);
 337         printk(KERN_INFO "lkdtm : Crash point unregistered\n");
 338 }
 339
 340 module_init(lkdtm_module_init);
 341 module_exit(lkdtm_module_exit);
 342
 343 MODULE_LICENSE("GPL");