2 * Kprobe module for testing crash dumps
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.
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.
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.
18 * Copyright (C) IBM Corporation, 2006
20 * Author: Ankita Garg <ankita@in.ibm.com>
22 * This module induces system failures at predefined crashpoints to
23 * evaluate the reliability of crash dumps obtained using different dumping
26 * It is adapted from the Linux Kernel Dump Test Tool by
27 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
29 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
31 * See Documentation/fault-injection/provoke-crashes.txt for instructions
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/buffer_head.h>
39 #include <linux/kprobes.h>
40 #include <linux/list.h>
41 #include <linux/init.h>
42 #include <linux/interrupt.h>
43 #include <linux/hrtimer.h>
44 #include <linux/slab.h>
45 #include <scsi/scsi_cmnd.h>
46 #include <linux/debugfs.h>
47 #include <linux/vmalloc.h>
48 #include <linux/mman.h>
51 #include <linux/ide.h>
55 * Make sure our attempts to over run the kernel stack doesn't trigger
56 * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
57 * recurse past the end of THREAD_SIZE by default.
59 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
60 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
62 #define REC_STACK_SIZE (THREAD_SIZE / 8)
64 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
66 #define DEFAULT_COUNT 10
71 CN_INT_HARDWARE_ENTRY,
91 CT_UNALIGNED_LOAD_STORE_WRITE,
92 CT_OVERWRITE_ALLOCATION,
107 static char* cp_name[] = {
108 "INT_HARDWARE_ENTRY",
119 static char* cp_type[] = {
127 "UNALIGNED_LOAD_STORE_WRITE",
128 "OVERWRITE_ALLOCATION",
143 static struct jprobe lkdtm;
145 static int lkdtm_parse_commandline(void);
146 static void lkdtm_handler(void);
148 static char* cpoint_name;
149 static char* cpoint_type;
150 static int cpoint_count = DEFAULT_COUNT;
151 static int recur_count = REC_NUM_DEFAULT;
153 static enum cname cpoint = CN_INVALID;
154 static enum ctype cptype = CT_NONE;
155 static int count = DEFAULT_COUNT;
156 static DEFINE_SPINLOCK(count_lock);
157 static DEFINE_SPINLOCK(lock_me_up);
159 static u8 data_area[EXEC_SIZE];
161 static const unsigned long rodata = 0xAA55AA55;
163 module_param(recur_count, int, 0644);
164 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
165 module_param(cpoint_name, charp, 0444);
166 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
167 module_param(cpoint_type, charp, 0444);
168 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
169 "hitting the crash point");
170 module_param(cpoint_count, int, 0644);
171 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
172 "crash point is to be hit to trigger action");
174 static unsigned int jp_do_irq(unsigned int irq)
181 static irqreturn_t jp_handle_irq_event(unsigned int irq,
182 struct irqaction *action)
189 static void jp_tasklet_action(struct softirq_action *a)
195 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
203 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
205 struct scan_control *sc)
212 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
213 const enum hrtimer_mode mode)
220 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
228 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
229 struct block_device *bdev, unsigned int cmd,
238 /* Return the crashpoint number or NONE if the name is invalid */
239 static enum ctype parse_cp_type(const char *what, size_t count)
243 for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
244 if (!strcmp(what, cp_type[i]))
251 static const char *cp_type_to_str(enum ctype type)
253 if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
256 return cp_type[type - 1];
259 static const char *cp_name_to_str(enum cname name)
261 if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
264 return cp_name[name - 1];
268 static int lkdtm_parse_commandline(void)
273 if (cpoint_count < 1 || recur_count < 1)
276 spin_lock_irqsave(&count_lock, flags);
277 count = cpoint_count;
278 spin_unlock_irqrestore(&count_lock, flags);
280 /* No special parameters */
281 if (!cpoint_type && !cpoint_name)
284 /* Neither or both of these need to be set */
285 if (!cpoint_type || !cpoint_name)
288 cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
289 if (cptype == CT_NONE)
292 for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
293 if (!strcmp(cpoint_name, cp_name[i])) {
299 /* Could not find a valid crash point */
303 static int recursive_loop(int remaining)
305 char buf[REC_STACK_SIZE];
307 /* Make sure compiler does not optimize this away. */
308 memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
312 return recursive_loop(remaining - 1);
315 static void do_nothing(void)
320 static noinline void corrupt_stack(void)
322 /* Use default char array length that triggers stack protection. */
325 memset((void *)data, 0, 64);
328 static void execute_location(void *dst)
330 void (*func)(void) = dst;
332 pr_info("attempting ok execution at %p\n", do_nothing);
335 memcpy(dst, do_nothing, EXEC_SIZE);
336 flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
337 pr_info("attempting bad execution at %p\n", func);
341 static void execute_user_location(void *dst)
343 /* Intentionally crossing kernel/user memory boundary. */
344 void (*func)(void) = dst;
346 pr_info("attempting ok execution at %p\n", do_nothing);
349 if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
351 flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
352 pr_info("attempting bad execution at %p\n", func);
356 static void lkdtm_do_action(enum ctype which)
376 (void) recursive_loop(recur_count);
378 case CT_CORRUPT_STACK:
381 case CT_UNALIGNED_LOAD_STORE_WRITE: {
382 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
385 u32 val = 0x12345678;
387 p = (u32 *)(data + 1);
393 case CT_OVERWRITE_ALLOCATION: {
395 u32 *data = kmalloc(len, GFP_KERNEL);
397 data[1024 / sizeof(u32)] = 0x12345678;
401 case CT_WRITE_AFTER_FREE: {
403 u32 *data = kmalloc(len, GFP_KERNEL);
407 memset(data, 0x78, len);
421 /* Must be called twice to trigger. */
422 spin_lock(&lock_me_up);
423 /* Let sparse know we intended to exit holding the lock. */
424 __release(&lock_me_up);
427 set_current_state(TASK_UNINTERRUPTIBLE);
431 execute_location(data_area);
433 case CT_EXEC_STACK: {
434 u8 stack_area[EXEC_SIZE];
435 execute_location(stack_area);
438 case CT_EXEC_KMALLOC: {
439 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
440 execute_location(kmalloc_area);
444 case CT_EXEC_VMALLOC: {
445 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
446 execute_location(vmalloc_area);
450 case CT_EXEC_USERSPACE: {
451 unsigned long user_addr;
453 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
454 PROT_READ | PROT_WRITE | PROT_EXEC,
455 MAP_ANONYMOUS | MAP_PRIVATE, 0);
456 if (user_addr >= TASK_SIZE) {
457 pr_warn("Failed to allocate user memory\n");
460 execute_user_location((void *)user_addr);
461 vm_munmap(user_addr, PAGE_SIZE);
464 case CT_ACCESS_USERSPACE: {
465 unsigned long user_addr, tmp;
468 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
469 PROT_READ | PROT_WRITE | PROT_EXEC,
470 MAP_ANONYMOUS | MAP_PRIVATE, 0);
471 if (user_addr >= TASK_SIZE) {
472 pr_warn("Failed to allocate user memory\n");
476 ptr = (unsigned long *)user_addr;
478 pr_info("attempting bad read at %p\n", ptr);
482 pr_info("attempting bad write at %p\n", ptr);
485 vm_munmap(user_addr, PAGE_SIZE);
492 ptr = (unsigned long *)&rodata;
494 pr_info("attempting bad write at %p\n", ptr);
506 static void lkdtm_handler(void)
511 spin_lock_irqsave(&count_lock, flags);
513 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
514 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
518 count = cpoint_count;
520 spin_unlock_irqrestore(&count_lock, flags);
523 lkdtm_do_action(cptype);
526 static int lkdtm_register_cpoint(enum cname which)
531 if (lkdtm.entry != NULL)
532 unregister_jprobe(&lkdtm);
536 lkdtm_do_action(cptype);
538 case CN_INT_HARDWARE_ENTRY:
539 lkdtm.kp.symbol_name = "do_IRQ";
540 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
542 case CN_INT_HW_IRQ_EN:
543 lkdtm.kp.symbol_name = "handle_IRQ_event";
544 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
546 case CN_INT_TASKLET_ENTRY:
547 lkdtm.kp.symbol_name = "tasklet_action";
548 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
551 lkdtm.kp.symbol_name = "ll_rw_block";
552 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
555 lkdtm.kp.symbol_name = "shrink_inactive_list";
556 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
559 lkdtm.kp.symbol_name = "hrtimer_start";
560 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
562 case CN_SCSI_DISPATCH_CMD:
563 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
564 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
568 lkdtm.kp.symbol_name = "generic_ide_ioctl";
569 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
571 pr_info("Crash point not available\n");
576 pr_info("Invalid Crash Point\n");
581 if ((ret = register_jprobe(&lkdtm)) < 0) {
582 pr_info("Couldn't register jprobe\n");
589 static ssize_t do_register_entry(enum cname which, struct file *f,
590 const char __user *user_buf, size_t count, loff_t *off)
595 if (count >= PAGE_SIZE)
598 buf = (char *)__get_free_page(GFP_KERNEL);
601 if (copy_from_user(buf, user_buf, count)) {
602 free_page((unsigned long) buf);
605 /* NULL-terminate and remove enter */
609 cptype = parse_cp_type(buf, count);
610 free_page((unsigned long) buf);
612 if (cptype == CT_NONE)
615 err = lkdtm_register_cpoint(which);
624 /* Generic read callback that just prints out the available crash types */
625 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
626 size_t count, loff_t *off)
631 buf = (char *)__get_free_page(GFP_KERNEL);
635 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
636 for (i = 0; i < ARRAY_SIZE(cp_type); i++)
637 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
640 out = simple_read_from_buffer(user_buf, count, off,
642 free_page((unsigned long) buf);
647 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
653 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
654 size_t count, loff_t *off)
656 return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
659 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
660 size_t count, loff_t *off)
662 return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
665 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
666 size_t count, loff_t *off)
668 return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
671 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
672 size_t count, loff_t *off)
674 return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
677 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
678 size_t count, loff_t *off)
680 return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
683 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
684 size_t count, loff_t *off)
686 return do_register_entry(CN_TIMERADD, f, buf, count, off);
689 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
690 const char __user *buf, size_t count, loff_t *off)
692 return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
695 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
696 size_t count, loff_t *off)
698 return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
701 /* Special entry to just crash directly. Available without KPROBEs */
702 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
703 size_t count, loff_t *off)
708 if (count >= PAGE_SIZE)
713 buf = (char *)__get_free_page(GFP_KERNEL);
716 if (copy_from_user(buf, user_buf, count)) {
717 free_page((unsigned long) buf);
720 /* NULL-terminate and remove enter */
724 type = parse_cp_type(buf, count);
725 free_page((unsigned long) buf);
729 pr_info("Performing direct entry %s\n", cp_type_to_str(type));
730 lkdtm_do_action(type);
738 const struct file_operations fops;
741 static const struct crash_entry crash_entries[] = {
742 {"DIRECT", {.read = lkdtm_debugfs_read,
743 .llseek = generic_file_llseek,
744 .open = lkdtm_debugfs_open,
745 .write = direct_entry} },
746 {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
747 .llseek = generic_file_llseek,
748 .open = lkdtm_debugfs_open,
749 .write = int_hardware_entry} },
750 {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
751 .llseek = generic_file_llseek,
752 .open = lkdtm_debugfs_open,
753 .write = int_hw_irq_en} },
754 {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
755 .llseek = generic_file_llseek,
756 .open = lkdtm_debugfs_open,
757 .write = int_tasklet_entry} },
758 {"FS_DEVRW", {.read = lkdtm_debugfs_read,
759 .llseek = generic_file_llseek,
760 .open = lkdtm_debugfs_open,
761 .write = fs_devrw_entry} },
762 {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
763 .llseek = generic_file_llseek,
764 .open = lkdtm_debugfs_open,
765 .write = mem_swapout_entry} },
766 {"TIMERADD", {.read = lkdtm_debugfs_read,
767 .llseek = generic_file_llseek,
768 .open = lkdtm_debugfs_open,
769 .write = timeradd_entry} },
770 {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
771 .llseek = generic_file_llseek,
772 .open = lkdtm_debugfs_open,
773 .write = scsi_dispatch_cmd_entry} },
774 {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
775 .llseek = generic_file_llseek,
776 .open = lkdtm_debugfs_open,
777 .write = ide_core_cp_entry} },
780 static struct dentry *lkdtm_debugfs_root;
782 static int __init lkdtm_module_init(void)
785 int n_debugfs_entries = 1; /* Assume only the direct entry */
788 /* Register debugfs interface */
789 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
790 if (!lkdtm_debugfs_root) {
791 pr_err("creating root dir failed\n");
795 #ifdef CONFIG_KPROBES
796 n_debugfs_entries = ARRAY_SIZE(crash_entries);
799 for (i = 0; i < n_debugfs_entries; i++) {
800 const struct crash_entry *cur = &crash_entries[i];
803 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
806 pr_err("could not create %s\n", cur->name);
811 if (lkdtm_parse_commandline() == -EINVAL) {
812 pr_info("Invalid command\n");
816 if (cpoint != CN_INVALID && cptype != CT_NONE) {
817 ret = lkdtm_register_cpoint(cpoint);
819 pr_info("Invalid crash point %d\n", cpoint);
822 pr_info("Crash point %s of type %s registered\n",
823 cpoint_name, cpoint_type);
825 pr_info("No crash points registered, enable through debugfs\n");
831 debugfs_remove_recursive(lkdtm_debugfs_root);
835 static void __exit lkdtm_module_exit(void)
837 debugfs_remove_recursive(lkdtm_debugfs_root);
839 unregister_jprobe(&lkdtm);
840 pr_info("Crash point unregistered\n");
843 module_init(lkdtm_module_init);
844 module_exit(lkdtm_module_exit);
846 MODULE_LICENSE("GPL");