drivers/misc/lkdtm_core.c

   1 /*
   2  * Linux Kernel Dump Test Module for testing kernel crashes conditions:
   3  * induces system failures at predefined crashpoints and under predefined
   4  * operational conditions in order to evaluate the reliability of kernel
   5  * sanity checking and crash dumps obtained using different dumping
   6  * solutions.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  *
  22  * Copyright (C) IBM Corporation, 2006
  23  *
  24  * Author: Ankita Garg <ankita@in.ibm.com>
  25  *
  26  * It is adapted from the Linux Kernel Dump Test Tool by
  27  * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
  28  *
  29  * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
  30  *
  31  * See Documentation/fault-injection/provoke-crashes.txt for instructions
  32  */
  33 #include "lkdtm.h"
  34 #include <linux/fs.h>
  35 #include <linux/module.h>
  36 #include <linux/buffer_head.h>
  37 #include <linux/kprobes.h>
  38 #include <linux/list.h>
  39 #include <linux/init.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/hrtimer.h>
  42 #include <linux/slab.h>
  43 #include <scsi/scsi_cmnd.h>
  44 #include <linux/debugfs.h>
  45
  46 #ifdef CONFIG_IDE
  47 #include <linux/ide.h>
  48 #endif
  49
  50 #define DEFAULT_COUNT 10
  51
  52 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
  53 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
  54                 size_t count, loff_t *off);
  55 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
  56                             size_t count, loff_t *off);
  57
  58 #ifdef CONFIG_KPROBES
  59 static void lkdtm_handler(void);
  60 static ssize_t lkdtm_debugfs_entry(struct file *f,
  61                                    const char __user *user_buf,
  62                                    size_t count, loff_t *off);
  63
  64
  65 /* jprobe entry point handlers. */
  66 static unsigned int jp_do_irq(unsigned int irq)
  67 {
  68         lkdtm_handler();
  69         jprobe_return();
  70         return 0;
  71 }
  72
  73 static irqreturn_t jp_handle_irq_event(unsigned int irq,
  74                                        struct irqaction *action)
  75 {
  76         lkdtm_handler();
  77         jprobe_return();
  78         return 0;
  79 }
  80
  81 static void jp_tasklet_action(struct softirq_action *a)
  82 {
  83         lkdtm_handler();
  84         jprobe_return();
  85 }
  86
  87 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
  88 {
  89         lkdtm_handler();
  90         jprobe_return();
  91 }
  92
  93 struct scan_control;
  94
  95 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
  96                                              struct zone *zone,
  97                                              struct scan_control *sc)
  98 {
  99         lkdtm_handler();
 100         jprobe_return();
 101         return 0;
 102 }
 103
 104 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
 105                             const enum hrtimer_mode mode)
 106 {
 107         lkdtm_handler();
 108         jprobe_return();
 109         return 0;
 110 }
 111
 112 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 113 {
 114         lkdtm_handler();
 115         jprobe_return();
 116         return 0;
 117 }
 118
 119 # ifdef CONFIG_IDE
 120 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
 121                         struct block_device *bdev, unsigned int cmd,
 122                         unsigned long arg)
 123 {
 124         lkdtm_handler();
 125         jprobe_return();
 126         return 0;
 127 }
 128 # endif
 129 #endif
 130
 131 /* Crash points */
 132 struct crashpoint {
 133         const char *name;
 134         const struct file_operations fops;
 135         struct jprobe jprobe;
 136 };
 137
 138 #define CRASHPOINT(_name, _write, _symbol, _entry)              \
 139         {                                                       \
 140                 .name = _name,                                  \
 141                 .fops = {                                       \
 142                         .read   = lkdtm_debugfs_read,           \
 143                         .llseek = generic_file_llseek,          \
 144                         .open   = lkdtm_debugfs_open,           \
 145                         .write  = _write,                       \
 146                 },                                              \
 147                 .jprobe = {                                     \
 148                         .kp.symbol_name = _symbol,              \
 149                         .entry = (kprobe_opcode_t *)_entry,     \
 150                 },                                              \
 151         }
 152
 153 /* Define the possible places where we can trigger a crash point. */
 154 struct crashpoint crashpoints[] = {
 155         CRASHPOINT("DIRECT",                    direct_entry,
 156                    NULL,                        NULL),
 157 #ifdef CONFIG_KPROBES
 158         CRASHPOINT("INT_HARDWARE_ENTRY",        lkdtm_debugfs_entry,
 159                    "do_IRQ",                    jp_do_irq),
 160         CRASHPOINT("INT_HW_IRQ_EN",             lkdtm_debugfs_entry,
 161                    "handle_IRQ_event",          jp_handle_irq_event),
 162         CRASHPOINT("INT_TASKLET_ENTRY",         lkdtm_debugfs_entry,
 163                    "tasklet_action",            jp_tasklet_action),
 164         CRASHPOINT("FS_DEVRW",                  lkdtm_debugfs_entry,
 165                    "ll_rw_block",               jp_ll_rw_block),
 166         CRASHPOINT("MEM_SWAPOUT",               lkdtm_debugfs_entry,
 167                    "shrink_inactive_list",      jp_shrink_inactive_list),
 168         CRASHPOINT("TIMERADD",                  lkdtm_debugfs_entry,
 169                    "hrtimer_start",             jp_hrtimer_start),
 170         CRASHPOINT("SCSI_DISPATCH_CMD",         lkdtm_debugfs_entry,
 171                    "scsi_dispatch_cmd",         jp_scsi_dispatch_cmd),
 172 # ifdef CONFIG_IDE
 173         CRASHPOINT("IDE_CORE_CP",               lkdtm_debugfs_entry,
 174                    "generic_ide_ioctl",         jp_generic_ide_ioctl),
 175 # endif
 176 #endif
 177 };
 178
 179
 180 /* Crash types. */
 181 struct crashtype {
 182         const char *name;
 183         void (*func)(void);
 184 };
 185
 186 #define CRASHTYPE(_name)                        \
 187         {                                       \
 188                 .name = __stringify(_name),     \
 189                 .func = lkdtm_ ## _name,        \
 190         }
 191
 192 /* Define the possible types of crashes that can be triggered. */
 193 struct crashtype crashtypes[] = {
 194         CRASHTYPE(PANIC),
 195         CRASHTYPE(BUG),
 196         CRASHTYPE(WARNING),
 197         CRASHTYPE(EXCEPTION),
 198         CRASHTYPE(LOOP),
 199         CRASHTYPE(OVERFLOW),
 200         CRASHTYPE(CORRUPT_STACK),
 201         CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
 202         CRASHTYPE(OVERWRITE_ALLOCATION),
 203         CRASHTYPE(WRITE_AFTER_FREE),
 204         CRASHTYPE(READ_AFTER_FREE),
 205         CRASHTYPE(WRITE_BUDDY_AFTER_FREE),
 206         CRASHTYPE(READ_BUDDY_AFTER_FREE),
 207         CRASHTYPE(SOFTLOCKUP),
 208         CRASHTYPE(HARDLOCKUP),
 209         CRASHTYPE(SPINLOCKUP),
 210         CRASHTYPE(HUNG_TASK),
 211         CRASHTYPE(EXEC_DATA),
 212         CRASHTYPE(EXEC_STACK),
 213         CRASHTYPE(EXEC_KMALLOC),
 214         CRASHTYPE(EXEC_VMALLOC),
 215         CRASHTYPE(EXEC_RODATA),
 216         CRASHTYPE(EXEC_USERSPACE),
 217         CRASHTYPE(ACCESS_USERSPACE),
 218         CRASHTYPE(WRITE_RO),
 219         CRASHTYPE(WRITE_RO_AFTER_INIT),
 220         CRASHTYPE(WRITE_KERN),
 221         CRASHTYPE(ATOMIC_UNDERFLOW),
 222         CRASHTYPE(ATOMIC_OVERFLOW),
 223         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
 224         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
 225         CRASHTYPE(USERCOPY_HEAP_FLAG_TO),
 226         CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
 227         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 228         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 229         CRASHTYPE(USERCOPY_STACK_BEYOND),
 230         CRASHTYPE(USERCOPY_KERNEL),
 231 };
 232
 233
 234 /* Global jprobe entry and crashtype. */
 235 static struct jprobe *lkdtm_jprobe;
 236 struct crashpoint *lkdtm_crashpoint;
 237 struct crashtype *lkdtm_crashtype;
 238
 239 /* Module parameters */
 240 static int recur_count = -1;
 241 module_param(recur_count, int, 0644);
 242 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 243
 244 static char* cpoint_name;
 245 module_param(cpoint_name, charp, 0444);
 246 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 247
 248 static char* cpoint_type;
 249 module_param(cpoint_type, charp, 0444);
 250 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 251                                 "hitting the crash point");
 252
 253 static int cpoint_count = DEFAULT_COUNT;
 254 module_param(cpoint_count, int, 0644);
 255 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 256                                 "crash point is to be hit to trigger action");
 257
 258
 259 /* Return the crashtype number or NULL if the name is invalid */
 260 static struct crashtype *find_crashtype(const char *name)
 261 {
 262         int i;
 263
 264         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 265                 if (!strcmp(name, crashtypes[i].name))
 266                         return &crashtypes[i];
 267         }
 268
 269         return NULL;
 270 }
 271
 272 /*
 273  * This is forced noinline just so it distinctly shows up in the stackdump
 274  * which makes validation of expected lkdtm crashes easier.
 275  */
 276 static noinline void lkdtm_do_action(struct crashtype *crashtype)
 277 {
 278         BUG_ON(!crashtype || !crashtype->func);
 279         crashtype->func();
 280 }
 281
 282 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 283                                  struct crashtype *crashtype)
 284 {
 285         int ret;
 286
 287         /* If this doesn't have a symbol, just call immediately. */
 288         if (!crashpoint->jprobe.kp.symbol_name) {
 289                 lkdtm_do_action(crashtype);
 290                 return 0;
 291         }
 292
 293         if (lkdtm_jprobe != NULL)
 294                 unregister_jprobe(lkdtm_jprobe);
 295
 296         lkdtm_crashpoint = crashpoint;
 297         lkdtm_crashtype = crashtype;
 298         lkdtm_jprobe = &crashpoint->jprobe;
 299         ret = register_jprobe(lkdtm_jprobe);
 300         if (ret < 0) {
 301                 pr_info("Couldn't register jprobe %s\n",
 302                         crashpoint->jprobe.kp.symbol_name);
 303                 lkdtm_jprobe = NULL;
 304                 lkdtm_crashpoint = NULL;
 305                 lkdtm_crashtype = NULL;
 306         }
 307
 308         return ret;
 309 }
 310
 311 #ifdef CONFIG_KPROBES
 312 /* Global crash counter and spinlock. */
 313 static int crash_count = DEFAULT_COUNT;
 314 static DEFINE_SPINLOCK(crash_count_lock);
 315
 316 /* Called by jprobe entry points. */
 317 static void lkdtm_handler(void)
 318 {
 319         unsigned long flags;
 320         bool do_it = false;
 321
 322         BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
 323
 324         spin_lock_irqsave(&crash_count_lock, flags);
 325         crash_count--;
 326         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 327                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
 328
 329         if (crash_count == 0) {
 330                 do_it = true;
 331                 crash_count = cpoint_count;
 332         }
 333         spin_unlock_irqrestore(&crash_count_lock, flags);
 334
 335         if (do_it)
 336                 lkdtm_do_action(lkdtm_crashtype);
 337 }
 338
 339 static ssize_t lkdtm_debugfs_entry(struct file *f,
 340                                    const char __user *user_buf,
 341                                    size_t count, loff_t *off)
 342 {
 343         struct crashpoint *crashpoint = file_inode(f)->i_private;
 344         struct crashtype *crashtype = NULL;
 345         char *buf;
 346         int err;
 347
 348         if (count >= PAGE_SIZE)
 349                 return -EINVAL;
 350
 351         buf = (char *)__get_free_page(GFP_KERNEL);
 352         if (!buf)
 353                 return -ENOMEM;
 354         if (copy_from_user(buf, user_buf, count)) {
 355                 free_page((unsigned long) buf);
 356                 return -EFAULT;
 357         }
 358         /* NULL-terminate and remove enter */
 359         buf[count] = '\0';
 360         strim(buf);
 361
 362         crashtype = find_crashtype(buf);
 363         free_page((unsigned long)buf);
 364
 365         if (!crashtype)
 366                 return -EINVAL;
 367
 368         err = lkdtm_register_cpoint(crashpoint, crashtype);
 369         if (err < 0)
 370                 return err;
 371
 372         *off += count;
 373
 374         return count;
 375 }
 376 #endif
 377
 378 /* Generic read callback that just prints out the available crash types */
 379 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 380                 size_t count, loff_t *off)
 381 {
 382         char *buf;
 383         int i, n, out;
 384
 385         buf = (char *)__get_free_page(GFP_KERNEL);
 386         if (buf == NULL)
 387                 return -ENOMEM;
 388
 389         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 390         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 391                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
 392                               crashtypes[i].name);
 393         }
 394         buf[n] = '\0';
 395
 396         out = simple_read_from_buffer(user_buf, count, off,
 397                                       buf, n);
 398         free_page((unsigned long) buf);
 399
 400         return out;
 401 }
 402
 403 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 404 {
 405         return 0;
 406 }
 407
 408 /* Special entry to just crash directly. Available without KPROBEs */
 409 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 410                 size_t count, loff_t *off)
 411 {
 412         struct crashtype *crashtype;
 413         char *buf;
 414
 415         if (count >= PAGE_SIZE)
 416                 return -EINVAL;
 417         if (count < 1)
 418                 return -EINVAL;
 419
 420         buf = (char *)__get_free_page(GFP_KERNEL);
 421         if (!buf)
 422                 return -ENOMEM;
 423         if (copy_from_user(buf, user_buf, count)) {
 424                 free_page((unsigned long) buf);
 425                 return -EFAULT;
 426         }
 427         /* NULL-terminate and remove enter */
 428         buf[count] = '\0';
 429         strim(buf);
 430
 431         crashtype = find_crashtype(buf);
 432         free_page((unsigned long) buf);
 433         if (!crashtype)
 434                 return -EINVAL;
 435
 436         pr_info("Performing direct entry %s\n", crashtype->name);
 437         lkdtm_do_action(crashtype);
 438         *off += count;
 439
 440         return count;
 441 }
 442
 443 static struct dentry *lkdtm_debugfs_root;
 444
 445 static int __init lkdtm_module_init(void)
 446 {
 447         struct crashpoint *crashpoint = NULL;
 448         struct crashtype *crashtype = NULL;
 449         int ret = -EINVAL;
 450         int i;
 451
 452         /* Neither or both of these need to be set */
 453         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
 454                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
 455                 return -EINVAL;
 456         }
 457
 458         if (cpoint_type) {
 459                 crashtype = find_crashtype(cpoint_type);
 460                 if (!crashtype) {
 461                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
 462                         return -EINVAL;
 463                 }
 464         }
 465
 466         if (cpoint_name) {
 467                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 468                         if (!strcmp(cpoint_name, crashpoints[i].name))
 469                                 crashpoint = &crashpoints[i];
 470                 }
 471
 472                 /* Refuse unknown crashpoints. */
 473                 if (!crashpoint) {
 474                         pr_err("Invalid crashpoint %s\n", cpoint_name);
 475                         return -EINVAL;
 476                 }
 477         }
 478
 479 #ifdef CONFIG_KPROBES
 480         /* Set crash count. */
 481         crash_count = cpoint_count;
 482 #endif
 483
 484         /* Handle test-specific initialization. */
 485         lkdtm_bugs_init(&recur_count);
 486         lkdtm_perms_init();
 487         lkdtm_usercopy_init();
 488
 489         /* Register debugfs interface */
 490         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 491         if (!lkdtm_debugfs_root) {
 492                 pr_err("creating root dir failed\n");
 493                 return -ENODEV;
 494         }
 495
 496         /* Install debugfs trigger files. */
 497         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 498                 struct crashpoint *cur = &crashpoints[i];
 499                 struct dentry *de;
 500
 501                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 502                                          cur, &cur->fops);
 503                 if (de == NULL) {
 504                         pr_err("could not create crashpoint %s\n", cur->name);
 505                         goto out_err;
 506                 }
 507         }
 508
 509         /* Install crashpoint if one was selected. */
 510         if (crashpoint) {
 511                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
 512                 if (ret < 0) {
 513                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
 514                         goto out_err;
 515                 }
 516                 pr_info("Crash point %s of type %s registered\n",
 517                         crashpoint->name, cpoint_type);
 518         } else {
 519                 pr_info("No crash points registered, enable through debugfs\n");
 520         }
 521
 522         return 0;
 523
 524 out_err:
 525         debugfs_remove_recursive(lkdtm_debugfs_root);
 526         return ret;
 527 }
 528
 529 static void __exit lkdtm_module_exit(void)
 530 {
 531         debugfs_remove_recursive(lkdtm_debugfs_root);
 532
 533         /* Handle test-specific clean-up. */
 534         lkdtm_usercopy_exit();
 535
 536         unregister_jprobe(lkdtm_jprobe);
 537         pr_info("Crash point unregistered\n");
 538 }
 539
 540 module_init(lkdtm_module_init);
 541 module_exit(lkdtm_module_exit);
 542
 543 MODULE_LICENSE("GPL");
 544 MODULE_DESCRIPTION("Kernel crash testing module");