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(EXEC_NULL),
 218         CRASHTYPE(ACCESS_USERSPACE),
 219         CRASHTYPE(ACCESS_NULL),
 220         CRASHTYPE(WRITE_RO),
 221         CRASHTYPE(WRITE_RO_AFTER_INIT),
 222         CRASHTYPE(WRITE_KERN),
 223         CRASHTYPE(ATOMIC_UNDERFLOW),
 224         CRASHTYPE(ATOMIC_OVERFLOW),
 225         CRASHTYPE(USERCOPY_HEAP_SIZE_TO),
 226         CRASHTYPE(USERCOPY_HEAP_SIZE_FROM),
 227         CRASHTYPE(USERCOPY_HEAP_FLAG_TO),
 228         CRASHTYPE(USERCOPY_HEAP_FLAG_FROM),
 229         CRASHTYPE(USERCOPY_STACK_FRAME_TO),
 230         CRASHTYPE(USERCOPY_STACK_FRAME_FROM),
 231         CRASHTYPE(USERCOPY_STACK_BEYOND),
 232         CRASHTYPE(USERCOPY_KERNEL),
 233 };
 234
 235
 236 /* Global jprobe entry and crashtype. */
 237 static struct jprobe *lkdtm_jprobe;
 238 struct crashpoint *lkdtm_crashpoint;
 239 struct crashtype *lkdtm_crashtype;
 240
 241 /* Module parameters */
 242 static int recur_count = -1;
 243 module_param(recur_count, int, 0644);
 244 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
 245
 246 static char* cpoint_name;
 247 module_param(cpoint_name, charp, 0444);
 248 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
 249
 250 static char* cpoint_type;
 251 module_param(cpoint_type, charp, 0444);
 252 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
 253                                 "hitting the crash point");
 254
 255 static int cpoint_count = DEFAULT_COUNT;
 256 module_param(cpoint_count, int, 0644);
 257 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 258                                 "crash point is to be hit to trigger action");
 259
 260
 261 /* Return the crashtype number or NULL if the name is invalid */
 262 static struct crashtype *find_crashtype(const char *name)
 263 {
 264         int i;
 265
 266         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 267                 if (!strcmp(name, crashtypes[i].name))
 268                         return &crashtypes[i];
 269         }
 270
 271         return NULL;
 272 }
 273
 274 /*
 275  * This is forced noinline just so it distinctly shows up in the stackdump
 276  * which makes validation of expected lkdtm crashes easier.
 277  */
 278 static noinline void lkdtm_do_action(struct crashtype *crashtype)
 279 {
 280         BUG_ON(!crashtype || !crashtype->func);
 281         crashtype->func();
 282 }
 283
 284 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 285                                  struct crashtype *crashtype)
 286 {
 287         int ret;
 288
 289         /* If this doesn't have a symbol, just call immediately. */
 290         if (!crashpoint->jprobe.kp.symbol_name) {
 291                 lkdtm_do_action(crashtype);
 292                 return 0;
 293         }
 294
 295         if (lkdtm_jprobe != NULL)
 296                 unregister_jprobe(lkdtm_jprobe);
 297
 298         lkdtm_crashpoint = crashpoint;
 299         lkdtm_crashtype = crashtype;
 300         lkdtm_jprobe = &crashpoint->jprobe;
 301         ret = register_jprobe(lkdtm_jprobe);
 302         if (ret < 0) {
 303                 pr_info("Couldn't register jprobe %s\n",
 304                         crashpoint->jprobe.kp.symbol_name);
 305                 lkdtm_jprobe = NULL;
 306                 lkdtm_crashpoint = NULL;
 307                 lkdtm_crashtype = NULL;
 308         }
 309
 310         return ret;
 311 }
 312
 313 #ifdef CONFIG_KPROBES
 314 /* Global crash counter and spinlock. */
 315 static int crash_count = DEFAULT_COUNT;
 316 static DEFINE_SPINLOCK(crash_count_lock);
 317
 318 /* Called by jprobe entry points. */
 319 static void lkdtm_handler(void)
 320 {
 321         unsigned long flags;
 322         bool do_it = false;
 323
 324         BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
 325
 326         spin_lock_irqsave(&crash_count_lock, flags);
 327         crash_count--;
 328         pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
 329                 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
 330
 331         if (crash_count == 0) {
 332                 do_it = true;
 333                 crash_count = cpoint_count;
 334         }
 335         spin_unlock_irqrestore(&crash_count_lock, flags);
 336
 337         if (do_it)
 338                 lkdtm_do_action(lkdtm_crashtype);
 339 }
 340
 341 static ssize_t lkdtm_debugfs_entry(struct file *f,
 342                                    const char __user *user_buf,
 343                                    size_t count, loff_t *off)
 344 {
 345         struct crashpoint *crashpoint = file_inode(f)->i_private;
 346         struct crashtype *crashtype = NULL;
 347         char *buf;
 348         int err;
 349
 350         if (count >= PAGE_SIZE)
 351                 return -EINVAL;
 352
 353         buf = (char *)__get_free_page(GFP_KERNEL);
 354         if (!buf)
 355                 return -ENOMEM;
 356         if (copy_from_user(buf, user_buf, count)) {
 357                 free_page((unsigned long) buf);
 358                 return -EFAULT;
 359         }
 360         /* NULL-terminate and remove enter */
 361         buf[count] = '\0';
 362         strim(buf);
 363
 364         crashtype = find_crashtype(buf);
 365         free_page((unsigned long)buf);
 366
 367         if (!crashtype)
 368                 return -EINVAL;
 369
 370         err = lkdtm_register_cpoint(crashpoint, crashtype);
 371         if (err < 0)
 372                 return err;
 373
 374         *off += count;
 375
 376         return count;
 377 }
 378 #endif
 379
 380 /* Generic read callback that just prints out the available crash types */
 381 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
 382                 size_t count, loff_t *off)
 383 {
 384         char *buf;
 385         int i, n, out;
 386
 387         buf = (char *)__get_free_page(GFP_KERNEL);
 388         if (buf == NULL)
 389                 return -ENOMEM;
 390
 391         n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
 392         for (i = 0; i < ARRAY_SIZE(crashtypes); i++) {
 393                 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n",
 394                               crashtypes[i].name);
 395         }
 396         buf[n] = '\0';
 397
 398         out = simple_read_from_buffer(user_buf, count, off,
 399                                       buf, n);
 400         free_page((unsigned long) buf);
 401
 402         return out;
 403 }
 404
 405 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
 406 {
 407         return 0;
 408 }
 409
 410 /* Special entry to just crash directly. Available without KPROBEs */
 411 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
 412                 size_t count, loff_t *off)
 413 {
 414         struct crashtype *crashtype;
 415         char *buf;
 416
 417         if (count >= PAGE_SIZE)
 418                 return -EINVAL;
 419         if (count < 1)
 420                 return -EINVAL;
 421
 422         buf = (char *)__get_free_page(GFP_KERNEL);
 423         if (!buf)
 424                 return -ENOMEM;
 425         if (copy_from_user(buf, user_buf, count)) {
 426                 free_page((unsigned long) buf);
 427                 return -EFAULT;
 428         }
 429         /* NULL-terminate and remove enter */
 430         buf[count] = '\0';
 431         strim(buf);
 432
 433         crashtype = find_crashtype(buf);
 434         free_page((unsigned long) buf);
 435         if (!crashtype)
 436                 return -EINVAL;
 437
 438         pr_info("Performing direct entry %s\n", crashtype->name);
 439         lkdtm_do_action(crashtype);
 440         *off += count;
 441
 442         return count;
 443 }
 444
 445 static struct dentry *lkdtm_debugfs_root;
 446
 447 static int __init lkdtm_module_init(void)
 448 {
 449         struct crashpoint *crashpoint = NULL;
 450         struct crashtype *crashtype = NULL;
 451         int ret = -EINVAL;
 452         int i;
 453
 454         /* Neither or both of these need to be set */
 455         if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
 456                 pr_err("Need both cpoint_type and cpoint_name or neither\n");
 457                 return -EINVAL;
 458         }
 459
 460         if (cpoint_type) {
 461                 crashtype = find_crashtype(cpoint_type);
 462                 if (!crashtype) {
 463                         pr_err("Unknown crashtype '%s'\n", cpoint_type);
 464                         return -EINVAL;
 465                 }
 466         }
 467
 468         if (cpoint_name) {
 469                 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 470                         if (!strcmp(cpoint_name, crashpoints[i].name))
 471                                 crashpoint = &crashpoints[i];
 472                 }
 473
 474                 /* Refuse unknown crashpoints. */
 475                 if (!crashpoint) {
 476                         pr_err("Invalid crashpoint %s\n", cpoint_name);
 477                         return -EINVAL;
 478                 }
 479         }
 480
 481 #ifdef CONFIG_KPROBES
 482         /* Set crash count. */
 483         crash_count = cpoint_count;
 484 #endif
 485
 486         /* Handle test-specific initialization. */
 487         lkdtm_bugs_init(&recur_count);
 488         lkdtm_perms_init();
 489         lkdtm_usercopy_init();
 490
 491         /* Register debugfs interface */
 492         lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
 493         if (!lkdtm_debugfs_root) {
 494                 pr_err("creating root dir failed\n");
 495                 return -ENODEV;
 496         }
 497
 498         /* Install debugfs trigger files. */
 499         for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
 500                 struct crashpoint *cur = &crashpoints[i];
 501                 struct dentry *de;
 502
 503                 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
 504                                          cur, &cur->fops);
 505                 if (de == NULL) {
 506                         pr_err("could not create crashpoint %s\n", cur->name);
 507                         goto out_err;
 508                 }
 509         }
 510
 511         /* Install crashpoint if one was selected. */
 512         if (crashpoint) {
 513                 ret = lkdtm_register_cpoint(crashpoint, crashtype);
 514                 if (ret < 0) {
 515                         pr_info("Invalid crashpoint %s\n", crashpoint->name);
 516                         goto out_err;
 517                 }
 518                 pr_info("Crash point %s of type %s registered\n",
 519                         crashpoint->name, cpoint_type);
 520         } else {
 521                 pr_info("No crash points registered, enable through debugfs\n");
 522         }
 523
 524         return 0;
 525
 526 out_err:
 527         debugfs_remove_recursive(lkdtm_debugfs_root);
 528         return ret;
 529 }
 530
 531 static void __exit lkdtm_module_exit(void)
 532 {
 533         debugfs_remove_recursive(lkdtm_debugfs_root);
 534
 535         /* Handle test-specific clean-up. */
 536         lkdtm_usercopy_exit();
 537
 538         if (lkdtm_jprobe != NULL)
 539                 unregister_jprobe(lkdtm_jprobe);
 540
 541         pr_info("Crash point unregistered\n");
 542 }
 543
 544 module_init(lkdtm_module_init);
 545 module_exit(lkdtm_module_exit);
 546
 547 MODULE_LICENSE("GPL");
 548 MODULE_DESCRIPTION("Kernel crash testing module");