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 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
30 *
31 * See Documentation/fault-injection/provoke-crashes.txt for instructions
32 */
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35 #include <linux/kernel.h>
36 #include <linux/fs.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>
49 #include <asm/cacheflush.h>
50
51 #ifdef CONFIG_IDE
52 #include <linux/ide.h>
53 #endif
54
55 /*
56 * Make sure our attempts to over run the kernel stack doesn't trigger
57 * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
58 * recurse past the end of THREAD_SIZE by default.
59 */
60 #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
61 #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
62 #else
63 #define REC_STACK_SIZE (THREAD_SIZE / 8)
64 #endif
65 #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
66
67 #define DEFAULT_COUNT 10
68 #define EXEC_SIZE 64
69
70 enum cname {
71 CN_INVALID,
72 CN_INT_HARDWARE_ENTRY,
73 CN_INT_HW_IRQ_EN,
74 CN_INT_TASKLET_ENTRY,
75 CN_FS_DEVRW,
76 CN_MEM_SWAPOUT,
77 CN_TIMERADD,
78 CN_SCSI_DISPATCH_CMD,
79 CN_IDE_CORE_CP,
80 CN_DIRECT,
81 };
82
83 enum ctype {
84 CT_NONE,
85 CT_PANIC,
86 CT_BUG,
87 CT_WARNING,
88 CT_EXCEPTION,
89 CT_LOOP,
90 CT_OVERFLOW,
91 CT_CORRUPT_STACK,
92 CT_UNALIGNED_LOAD_STORE_WRITE,
93 CT_OVERWRITE_ALLOCATION,
94 CT_WRITE_AFTER_FREE,
95 CT_SOFTLOCKUP,
96 CT_HARDLOCKUP,
97 CT_SPINLOCKUP,
98 CT_HUNG_TASK,
99 CT_EXEC_DATA,
100 CT_EXEC_STACK,
101 CT_EXEC_KMALLOC,
102 CT_EXEC_VMALLOC,
103 CT_EXEC_USERSPACE,
104 CT_ACCESS_USERSPACE,
105 CT_WRITE_RO,
106 CT_WRITE_RO_AFTER_INIT,
107 CT_WRITE_KERN,
108 };
109
110 static char* cp_name[] = {
111 "INT_HARDWARE_ENTRY",
112 "INT_HW_IRQ_EN",
113 "INT_TASKLET_ENTRY",
114 "FS_DEVRW",
115 "MEM_SWAPOUT",
116 "TIMERADD",
117 "SCSI_DISPATCH_CMD",
118 "IDE_CORE_CP",
119 "DIRECT",
120 };
121
122 static char* cp_type[] = {
123 "PANIC",
124 "BUG",
125 "WARNING",
126 "EXCEPTION",
127 "LOOP",
128 "OVERFLOW",
129 "CORRUPT_STACK",
130 "UNALIGNED_LOAD_STORE_WRITE",
131 "OVERWRITE_ALLOCATION",
132 "WRITE_AFTER_FREE",
133 "SOFTLOCKUP",
134 "HARDLOCKUP",
135 "SPINLOCKUP",
136 "HUNG_TASK",
137 "EXEC_DATA",
138 "EXEC_STACK",
139 "EXEC_KMALLOC",
140 "EXEC_VMALLOC",
141 "EXEC_USERSPACE",
142 "ACCESS_USERSPACE",
143 "WRITE_RO",
144 "WRITE_RO_AFTER_INIT",
145 "WRITE_KERN",
146 };
147
148 static struct jprobe lkdtm;
149
150 static int lkdtm_parse_commandline(void);
151 static void lkdtm_handler(void);
152
153 static char* cpoint_name;
154 static char* cpoint_type;
155 static int cpoint_count = DEFAULT_COUNT;
156 static int recur_count = REC_NUM_DEFAULT;
157
158 static enum cname cpoint = CN_INVALID;
159 static enum ctype cptype = CT_NONE;
160 static int count = DEFAULT_COUNT;
161 static DEFINE_SPINLOCK(count_lock);
162 static DEFINE_SPINLOCK(lock_me_up);
163
164 static u8 data_area[EXEC_SIZE];
165
166 static const unsigned long rodata = 0xAA55AA55;
167 static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
168
169 module_param(recur_count, int, 0644);
170 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
171 module_param(cpoint_name, charp, 0444);
172 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
173 module_param(cpoint_type, charp, 0444);
174 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
175 "hitting the crash point");
176 module_param(cpoint_count, int, 0644);
177 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
178 "crash point is to be hit to trigger action");
179
jp_do_irq(unsigned int irq)180 static unsigned int jp_do_irq(unsigned int irq)
181 {
182 lkdtm_handler();
183 jprobe_return();
184 return 0;
185 }
186
jp_handle_irq_event(unsigned int irq,struct irqaction * action)187 static irqreturn_t jp_handle_irq_event(unsigned int irq,
188 struct irqaction *action)
189 {
190 lkdtm_handler();
191 jprobe_return();
192 return 0;
193 }
194
jp_tasklet_action(struct softirq_action * a)195 static void jp_tasklet_action(struct softirq_action *a)
196 {
197 lkdtm_handler();
198 jprobe_return();
199 }
200
jp_ll_rw_block(int rw,int nr,struct buffer_head * bhs[])201 static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
202 {
203 lkdtm_handler();
204 jprobe_return();
205 }
206
207 struct scan_control;
208
jp_shrink_inactive_list(unsigned long max_scan,struct zone * zone,struct scan_control * sc)209 static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
210 struct zone *zone,
211 struct scan_control *sc)
212 {
213 lkdtm_handler();
214 jprobe_return();
215 return 0;
216 }
217
jp_hrtimer_start(struct hrtimer * timer,ktime_t tim,const enum hrtimer_mode mode)218 static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
219 const enum hrtimer_mode mode)
220 {
221 lkdtm_handler();
222 jprobe_return();
223 return 0;
224 }
225
jp_scsi_dispatch_cmd(struct scsi_cmnd * cmd)226 static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
227 {
228 lkdtm_handler();
229 jprobe_return();
230 return 0;
231 }
232
233 #ifdef CONFIG_IDE
jp_generic_ide_ioctl(ide_drive_t * drive,struct file * file,struct block_device * bdev,unsigned int cmd,unsigned long arg)234 static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
235 struct block_device *bdev, unsigned int cmd,
236 unsigned long arg)
237 {
238 lkdtm_handler();
239 jprobe_return();
240 return 0;
241 }
242 #endif
243
244 /* Return the crashpoint number or NONE if the name is invalid */
parse_cp_type(const char * what,size_t count)245 static enum ctype parse_cp_type(const char *what, size_t count)
246 {
247 int i;
248
249 for (i = 0; i < ARRAY_SIZE(cp_type); i++) {
250 if (!strcmp(what, cp_type[i]))
251 return i + 1;
252 }
253
254 return CT_NONE;
255 }
256
cp_type_to_str(enum ctype type)257 static const char *cp_type_to_str(enum ctype type)
258 {
259 if (type == CT_NONE || type < 0 || type > ARRAY_SIZE(cp_type))
260 return "None";
261
262 return cp_type[type - 1];
263 }
264
cp_name_to_str(enum cname name)265 static const char *cp_name_to_str(enum cname name)
266 {
267 if (name == CN_INVALID || name < 0 || name > ARRAY_SIZE(cp_name))
268 return "INVALID";
269
270 return cp_name[name - 1];
271 }
272
273
lkdtm_parse_commandline(void)274 static int lkdtm_parse_commandline(void)
275 {
276 int i;
277 unsigned long flags;
278
279 if (cpoint_count < 1 || recur_count < 1)
280 return -EINVAL;
281
282 spin_lock_irqsave(&count_lock, flags);
283 count = cpoint_count;
284 spin_unlock_irqrestore(&count_lock, flags);
285
286 /* No special parameters */
287 if (!cpoint_type && !cpoint_name)
288 return 0;
289
290 /* Neither or both of these need to be set */
291 if (!cpoint_type || !cpoint_name)
292 return -EINVAL;
293
294 cptype = parse_cp_type(cpoint_type, strlen(cpoint_type));
295 if (cptype == CT_NONE)
296 return -EINVAL;
297
298 for (i = 0; i < ARRAY_SIZE(cp_name); i++) {
299 if (!strcmp(cpoint_name, cp_name[i])) {
300 cpoint = i + 1;
301 return 0;
302 }
303 }
304
305 /* Could not find a valid crash point */
306 return -EINVAL;
307 }
308
recursive_loop(int remaining)309 static int recursive_loop(int remaining)
310 {
311 char buf[REC_STACK_SIZE];
312
313 /* Make sure compiler does not optimize this away. */
314 memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
315 if (!remaining)
316 return 0;
317 else
318 return recursive_loop(remaining - 1);
319 }
320
do_nothing(void)321 static void do_nothing(void)
322 {
323 return;
324 }
325
326 /* Must immediately follow do_nothing for size calculuations to work out. */
do_overwritten(void)327 static void do_overwritten(void)
328 {
329 pr_info("do_overwritten wasn't overwritten!\n");
330 return;
331 }
332
corrupt_stack(void)333 static noinline void corrupt_stack(void)
334 {
335 /* Use default char array length that triggers stack protection. */
336 char data[8];
337
338 memset((void *)data, 0, 64);
339 }
340
execute_location(void * dst)341 static void execute_location(void *dst)
342 {
343 void (*func)(void) = dst;
344
345 pr_info("attempting ok execution at %p\n", do_nothing);
346 do_nothing();
347
348 memcpy(dst, do_nothing, EXEC_SIZE);
349 flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
350 pr_info("attempting bad execution at %p\n", func);
351 func();
352 }
353
execute_user_location(void * dst)354 static void execute_user_location(void *dst)
355 {
356 /* Intentionally crossing kernel/user memory boundary. */
357 void (*func)(void) = dst;
358
359 pr_info("attempting ok execution at %p\n", do_nothing);
360 do_nothing();
361
362 if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))
363 return;
364 flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);
365 pr_info("attempting bad execution at %p\n", func);
366 func();
367 }
368
lkdtm_do_action(enum ctype which)369 static void lkdtm_do_action(enum ctype which)
370 {
371 switch (which) {
372 case CT_PANIC:
373 panic("dumptest");
374 break;
375 case CT_BUG:
376 BUG();
377 break;
378 case CT_WARNING:
379 WARN_ON(1);
380 break;
381 case CT_EXCEPTION:
382 *((int *) 0) = 0;
383 break;
384 case CT_LOOP:
385 for (;;)
386 ;
387 break;
388 case CT_OVERFLOW:
389 (void) recursive_loop(recur_count);
390 break;
391 case CT_CORRUPT_STACK:
392 corrupt_stack();
393 break;
394 case CT_UNALIGNED_LOAD_STORE_WRITE: {
395 static u8 data[5] __attribute__((aligned(4))) = {1, 2,
396 3, 4, 5};
397 u32 *p;
398 u32 val = 0x12345678;
399
400 p = (u32 *)(data + 1);
401 if (*p == 0)
402 val = 0x87654321;
403 *p = val;
404 break;
405 }
406 case CT_OVERWRITE_ALLOCATION: {
407 size_t len = 1020;
408 u32 *data = kmalloc(len, GFP_KERNEL);
409
410 data[1024 / sizeof(u32)] = 0x12345678;
411 kfree(data);
412 break;
413 }
414 case CT_WRITE_AFTER_FREE: {
415 size_t len = 1024;
416 u32 *data = kmalloc(len, GFP_KERNEL);
417
418 kfree(data);
419 schedule();
420 memset(data, 0x78, len);
421 break;
422 }
423 case CT_SOFTLOCKUP:
424 preempt_disable();
425 for (;;)
426 cpu_relax();
427 break;
428 case CT_HARDLOCKUP:
429 local_irq_disable();
430 for (;;)
431 cpu_relax();
432 break;
433 case CT_SPINLOCKUP:
434 /* Must be called twice to trigger. */
435 spin_lock(&lock_me_up);
436 /* Let sparse know we intended to exit holding the lock. */
437 __release(&lock_me_up);
438 break;
439 case CT_HUNG_TASK:
440 set_current_state(TASK_UNINTERRUPTIBLE);
441 schedule();
442 break;
443 case CT_EXEC_DATA:
444 execute_location(data_area);
445 break;
446 case CT_EXEC_STACK: {
447 u8 stack_area[EXEC_SIZE];
448 execute_location(stack_area);
449 break;
450 }
451 case CT_EXEC_KMALLOC: {
452 u32 *kmalloc_area = kmalloc(EXEC_SIZE, GFP_KERNEL);
453 execute_location(kmalloc_area);
454 kfree(kmalloc_area);
455 break;
456 }
457 case CT_EXEC_VMALLOC: {
458 u32 *vmalloc_area = vmalloc(EXEC_SIZE);
459 execute_location(vmalloc_area);
460 vfree(vmalloc_area);
461 break;
462 }
463 case CT_EXEC_USERSPACE: {
464 unsigned long user_addr;
465
466 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
467 PROT_READ | PROT_WRITE | PROT_EXEC,
468 MAP_ANONYMOUS | MAP_PRIVATE, 0);
469 if (user_addr >= TASK_SIZE) {
470 pr_warn("Failed to allocate user memory\n");
471 return;
472 }
473 execute_user_location((void *)user_addr);
474 vm_munmap(user_addr, PAGE_SIZE);
475 break;
476 }
477 case CT_ACCESS_USERSPACE: {
478 unsigned long user_addr, tmp = 0;
479 unsigned long *ptr;
480
481 user_addr = vm_mmap(NULL, 0, PAGE_SIZE,
482 PROT_READ | PROT_WRITE | PROT_EXEC,
483 MAP_ANONYMOUS | MAP_PRIVATE, 0);
484 if (user_addr >= TASK_SIZE) {
485 pr_warn("Failed to allocate user memory\n");
486 return;
487 }
488
489 if (copy_to_user((void __user *)user_addr, &tmp, sizeof(tmp))) {
490 pr_warn("copy_to_user failed\n");
491 vm_munmap(user_addr, PAGE_SIZE);
492 return;
493 }
494
495 ptr = (unsigned long *)user_addr;
496
497 pr_info("attempting bad read at %p\n", ptr);
498 tmp = *ptr;
499 tmp += 0xc0dec0de;
500
501 pr_info("attempting bad write at %p\n", ptr);
502 *ptr = tmp;
503
504 vm_munmap(user_addr, PAGE_SIZE);
505
506 break;
507 }
508 case CT_WRITE_RO: {
509 /* Explicitly cast away "const" for the test. */
510 unsigned long *ptr = (unsigned long *)&rodata;
511
512 pr_info("attempting bad rodata write at %p\n", ptr);
513 *ptr ^= 0xabcd1234;
514
515 break;
516 }
517 case CT_WRITE_RO_AFTER_INIT: {
518 unsigned long *ptr = &ro_after_init;
519
520 /*
521 * Verify we were written to during init. Since an Oops
522 * is considered a "success", a failure is to just skip the
523 * real test.
524 */
525 if ((*ptr & 0xAA) != 0xAA) {
526 pr_info("%p was NOT written during init!?\n", ptr);
527 break;
528 }
529
530 pr_info("attempting bad ro_after_init write at %p\n", ptr);
531 *ptr ^= 0xabcd1234;
532
533 break;
534 }
535 case CT_WRITE_KERN: {
536 size_t size;
537 unsigned char *ptr;
538
539 size = (unsigned long)do_overwritten -
540 (unsigned long)do_nothing;
541 ptr = (unsigned char *)do_overwritten;
542
543 pr_info("attempting bad %zu byte write at %p\n", size, ptr);
544 memcpy(ptr, (unsigned char *)do_nothing, size);
545 flush_icache_range((unsigned long)ptr,
546 (unsigned long)(ptr + size));
547
548 do_overwritten();
549 break;
550 }
551 case CT_NONE:
552 default:
553 break;
554 }
555
556 }
557
lkdtm_handler(void)558 static void lkdtm_handler(void)
559 {
560 unsigned long flags;
561 bool do_it = false;
562
563 spin_lock_irqsave(&count_lock, flags);
564 count--;
565 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
566 cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
567
568 if (count == 0) {
569 do_it = true;
570 count = cpoint_count;
571 }
572 spin_unlock_irqrestore(&count_lock, flags);
573
574 if (do_it)
575 lkdtm_do_action(cptype);
576 }
577
lkdtm_register_cpoint(enum cname which)578 static int lkdtm_register_cpoint(enum cname which)
579 {
580 int ret;
581
582 cpoint = CN_INVALID;
583 if (lkdtm.entry != NULL)
584 unregister_jprobe(&lkdtm);
585
586 switch (which) {
587 case CN_DIRECT:
588 lkdtm_do_action(cptype);
589 return 0;
590 case CN_INT_HARDWARE_ENTRY:
591 lkdtm.kp.symbol_name = "do_IRQ";
592 lkdtm.entry = (kprobe_opcode_t*) jp_do_irq;
593 break;
594 case CN_INT_HW_IRQ_EN:
595 lkdtm.kp.symbol_name = "handle_IRQ_event";
596 lkdtm.entry = (kprobe_opcode_t*) jp_handle_irq_event;
597 break;
598 case CN_INT_TASKLET_ENTRY:
599 lkdtm.kp.symbol_name = "tasklet_action";
600 lkdtm.entry = (kprobe_opcode_t*) jp_tasklet_action;
601 break;
602 case CN_FS_DEVRW:
603 lkdtm.kp.symbol_name = "ll_rw_block";
604 lkdtm.entry = (kprobe_opcode_t*) jp_ll_rw_block;
605 break;
606 case CN_MEM_SWAPOUT:
607 lkdtm.kp.symbol_name = "shrink_inactive_list";
608 lkdtm.entry = (kprobe_opcode_t*) jp_shrink_inactive_list;
609 break;
610 case CN_TIMERADD:
611 lkdtm.kp.symbol_name = "hrtimer_start";
612 lkdtm.entry = (kprobe_opcode_t*) jp_hrtimer_start;
613 break;
614 case CN_SCSI_DISPATCH_CMD:
615 lkdtm.kp.symbol_name = "scsi_dispatch_cmd";
616 lkdtm.entry = (kprobe_opcode_t*) jp_scsi_dispatch_cmd;
617 break;
618 case CN_IDE_CORE_CP:
619 #ifdef CONFIG_IDE
620 lkdtm.kp.symbol_name = "generic_ide_ioctl";
621 lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl;
622 #else
623 pr_info("Crash point not available\n");
624 return -EINVAL;
625 #endif
626 break;
627 default:
628 pr_info("Invalid Crash Point\n");
629 return -EINVAL;
630 }
631
632 cpoint = which;
633 if ((ret = register_jprobe(&lkdtm)) < 0) {
634 pr_info("Couldn't register jprobe\n");
635 cpoint = CN_INVALID;
636 }
637
638 return ret;
639 }
640
do_register_entry(enum cname which,struct file * f,const char __user * user_buf,size_t count,loff_t * off)641 static ssize_t do_register_entry(enum cname which, struct file *f,
642 const char __user *user_buf, size_t count, loff_t *off)
643 {
644 char *buf;
645 int err;
646
647 if (count >= PAGE_SIZE)
648 return -EINVAL;
649
650 buf = (char *)__get_free_page(GFP_KERNEL);
651 if (!buf)
652 return -ENOMEM;
653 if (copy_from_user(buf, user_buf, count)) {
654 free_page((unsigned long) buf);
655 return -EFAULT;
656 }
657 /* NULL-terminate and remove enter */
658 buf[count] = '\0';
659 strim(buf);
660
661 cptype = parse_cp_type(buf, count);
662 free_page((unsigned long) buf);
663
664 if (cptype == CT_NONE)
665 return -EINVAL;
666
667 err = lkdtm_register_cpoint(which);
668 if (err < 0)
669 return err;
670
671 *off += count;
672
673 return count;
674 }
675
676 /* Generic read callback that just prints out the available crash types */
lkdtm_debugfs_read(struct file * f,char __user * user_buf,size_t count,loff_t * off)677 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
678 size_t count, loff_t *off)
679 {
680 char *buf;
681 int i, n, out;
682
683 buf = (char *)__get_free_page(GFP_KERNEL);
684 if (buf == NULL)
685 return -ENOMEM;
686
687 n = snprintf(buf, PAGE_SIZE, "Available crash types:\n");
688 for (i = 0; i < ARRAY_SIZE(cp_type); i++)
689 n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]);
690 buf[n] = '\0';
691
692 out = simple_read_from_buffer(user_buf, count, off,
693 buf, n);
694 free_page((unsigned long) buf);
695
696 return out;
697 }
698
lkdtm_debugfs_open(struct inode * inode,struct file * file)699 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
700 {
701 return 0;
702 }
703
704
int_hardware_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)705 static ssize_t int_hardware_entry(struct file *f, const char __user *buf,
706 size_t count, loff_t *off)
707 {
708 return do_register_entry(CN_INT_HARDWARE_ENTRY, f, buf, count, off);
709 }
710
int_hw_irq_en(struct file * f,const char __user * buf,size_t count,loff_t * off)711 static ssize_t int_hw_irq_en(struct file *f, const char __user *buf,
712 size_t count, loff_t *off)
713 {
714 return do_register_entry(CN_INT_HW_IRQ_EN, f, buf, count, off);
715 }
716
int_tasklet_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)717 static ssize_t int_tasklet_entry(struct file *f, const char __user *buf,
718 size_t count, loff_t *off)
719 {
720 return do_register_entry(CN_INT_TASKLET_ENTRY, f, buf, count, off);
721 }
722
fs_devrw_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)723 static ssize_t fs_devrw_entry(struct file *f, const char __user *buf,
724 size_t count, loff_t *off)
725 {
726 return do_register_entry(CN_FS_DEVRW, f, buf, count, off);
727 }
728
mem_swapout_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)729 static ssize_t mem_swapout_entry(struct file *f, const char __user *buf,
730 size_t count, loff_t *off)
731 {
732 return do_register_entry(CN_MEM_SWAPOUT, f, buf, count, off);
733 }
734
timeradd_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)735 static ssize_t timeradd_entry(struct file *f, const char __user *buf,
736 size_t count, loff_t *off)
737 {
738 return do_register_entry(CN_TIMERADD, f, buf, count, off);
739 }
740
scsi_dispatch_cmd_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)741 static ssize_t scsi_dispatch_cmd_entry(struct file *f,
742 const char __user *buf, size_t count, loff_t *off)
743 {
744 return do_register_entry(CN_SCSI_DISPATCH_CMD, f, buf, count, off);
745 }
746
ide_core_cp_entry(struct file * f,const char __user * buf,size_t count,loff_t * off)747 static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf,
748 size_t count, loff_t *off)
749 {
750 return do_register_entry(CN_IDE_CORE_CP, f, buf, count, off);
751 }
752
753 /* Special entry to just crash directly. Available without KPROBEs */
direct_entry(struct file * f,const char __user * user_buf,size_t count,loff_t * off)754 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
755 size_t count, loff_t *off)
756 {
757 enum ctype type;
758 char *buf;
759
760 if (count >= PAGE_SIZE)
761 return -EINVAL;
762 if (count < 1)
763 return -EINVAL;
764
765 buf = (char *)__get_free_page(GFP_KERNEL);
766 if (!buf)
767 return -ENOMEM;
768 if (copy_from_user(buf, user_buf, count)) {
769 free_page((unsigned long) buf);
770 return -EFAULT;
771 }
772 /* NULL-terminate and remove enter */
773 buf[count] = '\0';
774 strim(buf);
775
776 type = parse_cp_type(buf, count);
777 free_page((unsigned long) buf);
778 if (type == CT_NONE)
779 return -EINVAL;
780
781 pr_info("Performing direct entry %s\n", cp_type_to_str(type));
782 lkdtm_do_action(type);
783 *off += count;
784
785 return count;
786 }
787
788 struct crash_entry {
789 const char *name;
790 const struct file_operations fops;
791 };
792
793 static const struct crash_entry crash_entries[] = {
794 {"DIRECT", {.read = lkdtm_debugfs_read,
795 .llseek = generic_file_llseek,
796 .open = lkdtm_debugfs_open,
797 .write = direct_entry} },
798 {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read,
799 .llseek = generic_file_llseek,
800 .open = lkdtm_debugfs_open,
801 .write = int_hardware_entry} },
802 {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read,
803 .llseek = generic_file_llseek,
804 .open = lkdtm_debugfs_open,
805 .write = int_hw_irq_en} },
806 {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read,
807 .llseek = generic_file_llseek,
808 .open = lkdtm_debugfs_open,
809 .write = int_tasklet_entry} },
810 {"FS_DEVRW", {.read = lkdtm_debugfs_read,
811 .llseek = generic_file_llseek,
812 .open = lkdtm_debugfs_open,
813 .write = fs_devrw_entry} },
814 {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read,
815 .llseek = generic_file_llseek,
816 .open = lkdtm_debugfs_open,
817 .write = mem_swapout_entry} },
818 {"TIMERADD", {.read = lkdtm_debugfs_read,
819 .llseek = generic_file_llseek,
820 .open = lkdtm_debugfs_open,
821 .write = timeradd_entry} },
822 {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read,
823 .llseek = generic_file_llseek,
824 .open = lkdtm_debugfs_open,
825 .write = scsi_dispatch_cmd_entry} },
826 {"IDE_CORE_CP", {.read = lkdtm_debugfs_read,
827 .llseek = generic_file_llseek,
828 .open = lkdtm_debugfs_open,
829 .write = ide_core_cp_entry} },
830 };
831
832 static struct dentry *lkdtm_debugfs_root;
833
lkdtm_module_init(void)834 static int __init lkdtm_module_init(void)
835 {
836 int ret = -EINVAL;
837 int n_debugfs_entries = 1; /* Assume only the direct entry */
838 int i;
839
840 /* Make sure we can write to __ro_after_init values during __init */
841 ro_after_init |= 0xAA;
842
843 /* Register debugfs interface */
844 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
845 if (!lkdtm_debugfs_root) {
846 pr_err("creating root dir failed\n");
847 return -ENODEV;
848 }
849
850 #ifdef CONFIG_KPROBES
851 n_debugfs_entries = ARRAY_SIZE(crash_entries);
852 #endif
853
854 for (i = 0; i < n_debugfs_entries; i++) {
855 const struct crash_entry *cur = &crash_entries[i];
856 struct dentry *de;
857
858 de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root,
859 NULL, &cur->fops);
860 if (de == NULL) {
861 pr_err("could not create %s\n", cur->name);
862 goto out_err;
863 }
864 }
865
866 if (lkdtm_parse_commandline() == -EINVAL) {
867 pr_info("Invalid command\n");
868 goto out_err;
869 }
870
871 if (cpoint != CN_INVALID && cptype != CT_NONE) {
872 ret = lkdtm_register_cpoint(cpoint);
873 if (ret < 0) {
874 pr_info("Invalid crash point %d\n", cpoint);
875 goto out_err;
876 }
877 pr_info("Crash point %s of type %s registered\n",
878 cpoint_name, cpoint_type);
879 } else {
880 pr_info("No crash points registered, enable through debugfs\n");
881 }
882
883 return 0;
884
885 out_err:
886 debugfs_remove_recursive(lkdtm_debugfs_root);
887 return ret;
888 }
889
lkdtm_module_exit(void)890 static void __exit lkdtm_module_exit(void)
891 {
892 debugfs_remove_recursive(lkdtm_debugfs_root);
893
894 unregister_jprobe(&lkdtm);
895 pr_info("Crash point unregistered\n");
896 }
897
898 module_init(lkdtm_module_init);
899 module_exit(lkdtm_module_exit);
900
901 MODULE_LICENSE("GPL");
902 MODULE_DESCRIPTION("Kprobe module for testing crash dumps");
903