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/module.h>
  48 #include <linux/kprobes.h>
  49 #include <linux/kallsyms.h>
  50 #include <linux/init.h>
  51 #include <linux/irq.h>
  52 #include <linux/interrupt.h>
  53 #include <scsi/scsi_cmnd.h>
  54
  55 #ifdef CONFIG_IDE
  56 #include <linux/ide.h>
  57 #endif
  58
  59 #define NUM_CPOINTS 8
  60 #define NUM_CPOINT_TYPES 5
  61 #define DEFAULT_COUNT 10
  62 #define REC_NUM_DEFAULT 10
  63
  64 enum cname {
  65         INVALID,
  66         INT_HARDWARE_ENTRY,
  67         INT_HW_IRQ_EN,
  68         INT_TASKLET_ENTRY,
  69         FS_DEVRW,
  70         MEM_SWAPOUT,
  71         TIMERADD,
  72         SCSI_DISPATCH_CMD,
  73         IDE_CORE_CP
  74 };
  75
  76 enum ctype {
  77         NONE,
  78         PANIC,
  79         BUG,
  80         EXCEPTION,
  81         LOOP,
  82         OVERFLOW
  83 };
  84
  85 static char* cp_name[] = {
  86         "INT_HARDWARE_ENTRY",
  87         "INT_HW_IRQ_EN",
  88         "INT_TASKLET_ENTRY",
  89         "FS_DEVRW",
  90         "MEM_SWAPOUT",
  91         "TIMERADD",
  92         "SCSI_DISPATCH_CMD",
  93         "IDE_CORE_CP"
  94 };
  95
  96 static char* cp_type[] = {
  97         "PANIC",
  98         "BUG",
  99         "EXCEPTION",
 100         "LOOP",
 101         "OVERFLOW"
 102 };
 103
 104 static struct jprobe lkdtm;
 105
 106 static int lkdtm_parse_commandline(void);
 107 static void lkdtm_handler(void);
 108
 109 static char* cpoint_name = INVALID;
 110 static char* cpoint_type = NONE;
 111 static int cpoint_count = DEFAULT_COUNT;
 112 static int recur_count = REC_NUM_DEFAULT;
 113
 114 static enum cname cpoint = INVALID;
 115 static enum ctype cptype = NONE;
 116 static int count = DEFAULT_COUNT;
 117
 118 module_param(recur_count, int, 0644);
 119 MODULE_PARM_DESC(recur_count, "Recurcion level for the stack overflow test,\
 120                                  default is 10");
 121 module_param(cpoint_name, charp, 0644);
 122 MODULE_PARM_DESC(cpoint_name, "Crash Point, where kernel is to be crashed");
 123 module_param(cpoint_type, charp, 06444);
 124 MODULE_PARM_DESC(cpoint_type, "Crash Point Type, action to be taken on\
 125                                 hitting the crash point");
 126 module_param(cpoint_count, int, 06444);
 127 MODULE_PARM_DESC(cpoint_count, "Crash Point Count, number of times the \
 128                                 crash point is to be hit to trigger action");
 129
 130 unsigned int jp_do_irq(unsigned int irq)
 131 {
 132         lkdtm_handler();
 133         jprobe_return();
 134         return 0;
 135 }
 136
 137 irqreturn_t jp_handle_irq_event(unsigned int irq, struct irqaction *action)
 138 {
 139         lkdtm_handler();
 140         jprobe_return();
 141         return 0;
 142 }
 143
 144 void jp_tasklet_action(struct softirq_action *a)
 145 {
 146         lkdtm_handler();
 147         jprobe_return();
 148 }
 149
 150 void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 151 {
 152         lkdtm_handler();
 153         jprobe_return();
 154 }
 155
 156 struct scan_control;
 157
 158 unsigned long jp_shrink_page_list(struct list_head *page_list,
 159                                         struct scan_control *sc)
 160 {
 161         lkdtm_handler();
 162         jprobe_return();
 163         return 0;
 164 }
 165
 166 int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 167                                 const enum hrtimer_mode mode)
 168 {
 169         lkdtm_handler();
 170         jprobe_return();
 171         return 0;
 172 }
 173
 174 int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 175 {
 176         lkdtm_handler();
 177         jprobe_return();
 178         return 0;
 179 }
 180
 181 #ifdef CONFIG_IDE
 182 int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 183                         struct block_device *bdev, unsigned int cmd,
 184                         unsigned long arg)
 185 {
 186         lkdtm_handler();
 187         jprobe_return();
 188         return 0;
 189 }
 190 #endif
 191
 192 static int lkdtm_parse_commandline(void)
 193 {
 194         int i;
 195
 196         if (cpoint_name == INVALID || cpoint_type == NONE ||
 197                                         cpoint_count < 1 || recur_count < 1)
 198                 return -EINVAL;
 199
 200         for (i = 0; i < NUM_CPOINTS; ++i) {
 201                 if (!strcmp(cpoint_name, cp_name[i])) {
 202                         cpoint = i + 1;
 203                         break;
 204                 }
 205         }
 206
 207         for (i = 0; i < NUM_CPOINT_TYPES; ++i) {
 208                 if (!strcmp(cpoint_type, cp_type[i])) {
 209                         cptype = i + 1;
 210                         break;
 211                 }
 212         }
 213
 214         if (cpoint == INVALID || cptype == NONE)
 215                 return -EINVAL;
 216
 217         count = cpoint_count;
 218
 219         return 0;
 220 }
 221
 222 static int recursive_loop(int a)
 223 {
 224         char buf[1024];
 225
 226         memset(buf,0xFF,1024);
 227         recur_count--;
 228         if (!recur_count)
 229                 return 0;
 230         else
 231                 return recursive_loop(a);
 232 }
 233
 234 void lkdtm_handler(void)
 235 {
 236         printk(KERN_INFO "lkdtm : Crash point %s of type %s hit\n",
 237                                          cpoint_name, cpoint_type);
 238         --count;
 239
 240         if (count == 0) {
 241                 switch (cptype) {
 242                 case NONE:
 243                         break;
 244                 case PANIC:
 245                         printk(KERN_INFO "lkdtm : PANIC\n");
 246                         panic("dumptest");
 247                         break;
 248                 case BUG:
 249                         printk(KERN_INFO "lkdtm : BUG\n");
 250                         BUG();
 251                         break;
 252                 case EXCEPTION:
 253                         printk(KERN_INFO "lkdtm : EXCEPTION\n");
 254                         *((int *) 0) = 0;
 255                         break;
 256                 case LOOP:
 257                         printk(KERN_INFO "lkdtm : LOOP\n");
 258                         for (;;);
 259                         break;
 260                 case OVERFLOW:
 261                         printk(KERN_INFO "lkdtm : OVERFLOW\n");
 262                         (void) recursive_loop(0);
 263                         break;
 264                 default:
 265                         break;
 266                 }
 267                 count = cpoint_count;
 268         }
 269 }
 270
 271 int lkdtm_module_init(void)
 272 {
 273         int ret;
 274
 275         if (lkdtm_parse_commandline() == -EINVAL) {
 276                 printk(KERN_INFO "lkdtm : Invalid command\n");
 277                 return -EINVAL;
 278         }
 279
 280         switch (cpoint) {
 281         case INT_HARDWARE_ENTRY:
 282                 lkdtm.kp.symbol_name = "__do_IRQ";
 283                 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
 284                 break;
 285         case INT_HW_IRQ_EN:
 286                 lkdtm.kp.symbol_name = "handle_IRQ_event";
 287                 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
 288                 break;
 289         case INT_TASKLET_ENTRY:
 290                 lkdtm.kp.symbol_name = "tasklet_action";
 291                 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
 292                 break;
 293         case FS_DEVRW:
 294                 lkdtm.kp.symbol_name = "ll_rw_block";
 295                 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
 296                 break;
 297         case MEM_SWAPOUT:
 298                 lkdtm.kp.symbol_name = "shrink_page_list";
 299                 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_page_list;
 300                 break;
 301         case TIMERADD:
 302                 lkdtm.kp.symbol_name = "hrtimer_start";
 303                 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
 304                 break;
 305         case SCSI_DISPATCH_CMD:
 306                 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
 307                 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
 308                 break;
 309         case IDE_CORE_CP:
 310 #ifdef CONFIG_IDE
 311                 lkdtm.kp.symbol_name = "generic_ide_ioctl";
 312                 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
 313 #else
 314                 printk(KERN_INFO "lkdtm : Crash point not available\n");
 315 #endif
 316                 break;
 317         default:
 318                 printk(KERN_INFO "lkdtm : Invalid Crash Point\n");
 319                 break;
 320         }
 321
 322         if ((ret = register_jprobe(&lkdtm)) < 0) {
 323                 printk(KERN_INFO "lkdtm : Couldn't register jprobe\n");
 324                 return ret;
 325         }
 326
 327         printk(KERN_INFO "lkdtm : Crash point %s of type %s registered\n",
 328                                                 cpoint_name, cpoint_type);
 329         return 0;
 330 }
 331
 332 void lkdtm_module_exit(void)
 333 {
 334         unregister_jprobe(&lkdtm);
 335         printk(KERN_INFO "lkdtm : Crash point unregistered\n");
 336 }
 337
 338 module_init(lkdtm_module_init);
 339 module_exit(lkdtm_module_exit);
 340
 341 MODULE_LICENSE("GPL");