1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Linux Kernel Dump Test Module for testing kernel crashes conditions:
4 * induces system failures at predefined crashpoints and under predefined
5 * operational conditions in order to evaluate the reliability of kernel
6 * sanity checking and crash dumps obtained using different dumping
9 * Copyright (C) IBM Corporation, 2006
11 * Author: Ankita Garg <ankita@in.ibm.com>
13 * It is adapted from the Linux Kernel Dump Test Tool by
14 * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net>
16 * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
18 * See Documentation/fault-injection/provoke-crashes.rst for instructions
22 #include <linux/module.h>
23 #include <linux/buffer_head.h>
24 #include <linux/kprobes.h>
25 #include <linux/list.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/debugfs.h>
29 #include <linux/utsname.h>
31 #define DEFAULT_COUNT 10
33 static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
34 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
35 size_t count, loff_t *off);
36 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
37 size_t count, loff_t *off);
40 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
41 static ssize_t lkdtm_debugfs_entry(struct file *f,
42 const char __user *user_buf,
43 size_t count, loff_t *off);
44 # define CRASHPOINT_KPROBE(_symbol) \
46 .symbol_name = (_symbol), \
47 .pre_handler = lkdtm_kprobe_handler, \
49 # define CRASHPOINT_WRITE(_symbol) \
50 (_symbol) ? lkdtm_debugfs_entry : direct_entry
52 # define CRASHPOINT_KPROBE(_symbol)
53 # define CRASHPOINT_WRITE(_symbol) direct_entry
59 const struct file_operations fops;
63 #define CRASHPOINT(_name, _symbol) \
67 .read = lkdtm_debugfs_read, \
68 .llseek = generic_file_llseek, \
69 .open = lkdtm_debugfs_open, \
70 .write = CRASHPOINT_WRITE(_symbol) \
72 CRASHPOINT_KPROBE(_symbol) \
75 /* Define the possible places where we can trigger a crash point. */
76 static struct crashpoint crashpoints[] = {
77 CRASHPOINT("DIRECT", NULL),
79 CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
80 CRASHPOINT("INT_HW_IRQ_EN", "handle_irq_event"),
81 CRASHPOINT("INT_TASKLET_ENTRY", "tasklet_action"),
82 CRASHPOINT("FS_SUBMIT_BH", "submit_bh"),
83 CRASHPOINT("MEM_SWAPOUT", "shrink_inactive_list"),
84 CRASHPOINT("TIMERADD", "hrtimer_start"),
85 CRASHPOINT("SCSI_QUEUE_RQ", "scsi_queue_rq"),
89 /* List of possible types for crashes that can be triggered. */
90 static const struct crashtype_category *crashtype_categories[] = {
96 &stackleak_crashtypes,
99 #ifdef CONFIG_PPC_64S_HASH_MMU
104 /* Global kprobe entry and crashtype. */
105 static struct kprobe *lkdtm_kprobe;
106 static struct crashpoint *lkdtm_crashpoint;
107 static const struct crashtype *lkdtm_crashtype;
109 /* Module parameters */
110 static int recur_count = -1;
111 module_param(recur_count, int, 0644);
112 MODULE_PARM_DESC(recur_count, " Recursion level for the stack overflow test");
114 static char* cpoint_name;
115 module_param(cpoint_name, charp, 0444);
116 MODULE_PARM_DESC(cpoint_name, " Crash Point, where kernel is to be crashed");
118 static char* cpoint_type;
119 module_param(cpoint_type, charp, 0444);
120 MODULE_PARM_DESC(cpoint_type, " Crash Point Type, action to be taken on "\
121 "hitting the crash point");
123 static int cpoint_count = DEFAULT_COUNT;
124 module_param(cpoint_count, int, 0644);
125 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
126 "crash point is to be hit to trigger action");
129 * For test debug reporting when CI systems provide terse summaries.
130 * TODO: Remove this once reasonable reporting exists in most CI systems:
131 * https://lore.kernel.org/lkml/CAHk-=wiFvfkoFixTapvvyPMN9pq5G-+Dys2eSyBa1vzDGAO5+A@mail.gmail.com
133 char *lkdtm_kernel_info;
135 /* Return the crashtype number or NULL if the name is invalid */
136 static const struct crashtype *find_crashtype(const char *name)
140 for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
141 for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
142 struct crashtype *crashtype;
144 crashtype = &crashtype_categories[cat]->crashtypes[idx];
145 if (!strcmp(name, crashtype->name))
154 * This is forced noinline just so it distinctly shows up in the stackdump
155 * which makes validation of expected lkdtm crashes easier.
157 static noinline void lkdtm_do_action(const struct crashtype *crashtype)
159 if (WARN_ON(!crashtype || !crashtype->func))
164 static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
165 const struct crashtype *crashtype)
169 /* If this doesn't have a symbol, just call immediately. */
170 if (!crashpoint->kprobe.symbol_name) {
171 lkdtm_do_action(crashtype);
175 if (lkdtm_kprobe != NULL)
176 unregister_kprobe(lkdtm_kprobe);
178 lkdtm_crashpoint = crashpoint;
179 lkdtm_crashtype = crashtype;
180 lkdtm_kprobe = &crashpoint->kprobe;
181 ret = register_kprobe(lkdtm_kprobe);
183 pr_info("Couldn't register kprobe %s\n",
184 crashpoint->kprobe.symbol_name);
186 lkdtm_crashpoint = NULL;
187 lkdtm_crashtype = NULL;
193 #ifdef CONFIG_KPROBES
194 /* Global crash counter and spinlock. */
195 static int crash_count = DEFAULT_COUNT;
196 static DEFINE_SPINLOCK(crash_count_lock);
198 /* Called by kprobe entry points. */
199 static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
204 if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
207 spin_lock_irqsave(&crash_count_lock, flags);
209 pr_info("Crash point %s of type %s hit, trigger in %d rounds\n",
210 lkdtm_crashpoint->name, lkdtm_crashtype->name, crash_count);
212 if (crash_count == 0) {
214 crash_count = cpoint_count;
216 spin_unlock_irqrestore(&crash_count_lock, flags);
219 lkdtm_do_action(lkdtm_crashtype);
224 static ssize_t lkdtm_debugfs_entry(struct file *f,
225 const char __user *user_buf,
226 size_t count, loff_t *off)
228 struct crashpoint *crashpoint = file_inode(f)->i_private;
229 const struct crashtype *crashtype = NULL;
233 if (count >= PAGE_SIZE)
236 buf = (char *)__get_free_page(GFP_KERNEL);
239 if (copy_from_user(buf, user_buf, count)) {
240 free_page((unsigned long) buf);
243 /* NULL-terminate and remove enter */
247 crashtype = find_crashtype(buf);
248 free_page((unsigned long)buf);
253 err = lkdtm_register_cpoint(crashpoint, crashtype);
263 /* Generic read callback that just prints out the available crash types */
264 static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
265 size_t count, loff_t *off)
271 buf = (char *)__get_free_page(GFP_KERNEL);
275 n = scnprintf(buf, PAGE_SIZE, "Available crash types:\n");
277 for (cat = 0; cat < ARRAY_SIZE(crashtype_categories); cat++) {
278 for (idx = 0; idx < crashtype_categories[cat]->len; idx++) {
279 struct crashtype *crashtype;
281 crashtype = &crashtype_categories[cat]->crashtypes[idx];
282 n += scnprintf(buf + n, PAGE_SIZE - n, "%s\n",
288 out = simple_read_from_buffer(user_buf, count, off,
290 free_page((unsigned long) buf);
295 static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
300 /* Special entry to just crash directly. Available without KPROBEs */
301 static ssize_t direct_entry(struct file *f, const char __user *user_buf,
302 size_t count, loff_t *off)
304 const struct crashtype *crashtype;
307 if (count >= PAGE_SIZE)
312 buf = (char *)__get_free_page(GFP_KERNEL);
315 if (copy_from_user(buf, user_buf, count)) {
316 free_page((unsigned long) buf);
319 /* NULL-terminate and remove enter */
323 crashtype = find_crashtype(buf);
324 free_page((unsigned long) buf);
328 pr_info("Performing direct entry %s\n", crashtype->name);
329 lkdtm_do_action(crashtype);
337 * To avoid needing to export parse_args(), just don't use this code
338 * when LKDTM is built as a module.
340 struct check_cmdline_args {
345 static int lkdtm_parse_one(char *param, char *val,
346 const char *unused, void *arg)
348 struct check_cmdline_args *args = arg;
350 /* short circuit if we already found a value. */
351 if (args->value != -ESRCH)
353 if (strncmp(param, args->param, strlen(args->param)) == 0) {
357 ret = kstrtobool(val, &bool_result);
359 args->value = bool_result;
364 int lkdtm_check_bool_cmdline(const char *param)
367 struct check_cmdline_args args = {
372 command_line = kstrdup(saved_command_line, GFP_KERNEL);
376 parse_args("Setting sysctl args", command_line,
377 NULL, 0, -1, -1, &args, lkdtm_parse_one);
385 static struct dentry *lkdtm_debugfs_root;
387 static int __init lkdtm_module_init(void)
389 struct crashpoint *crashpoint = NULL;
390 const struct crashtype *crashtype = NULL;
394 /* Neither or both of these need to be set */
395 if ((cpoint_type || cpoint_name) && !(cpoint_type && cpoint_name)) {
396 pr_err("Need both cpoint_type and cpoint_name or neither\n");
401 crashtype = find_crashtype(cpoint_type);
403 pr_err("Unknown crashtype '%s'\n", cpoint_type);
409 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
410 if (!strcmp(cpoint_name, crashpoints[i].name))
411 crashpoint = &crashpoints[i];
414 /* Refuse unknown crashpoints. */
416 pr_err("Invalid crashpoint %s\n", cpoint_name);
421 #ifdef CONFIG_KPROBES
422 /* Set crash count. */
423 crash_count = cpoint_count;
426 /* Common initialization. */
427 lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
428 init_uts_ns.name.release,
429 init_uts_ns.name.machine);
431 /* Handle test-specific initialization. */
432 lkdtm_bugs_init(&recur_count);
434 lkdtm_usercopy_init();
437 /* Register debugfs interface */
438 lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL);
440 /* Install debugfs trigger files. */
441 for (i = 0; i < ARRAY_SIZE(crashpoints); i++) {
442 struct crashpoint *cur = &crashpoints[i];
444 debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, cur,
448 /* Install crashpoint if one was selected. */
450 ret = lkdtm_register_cpoint(crashpoint, crashtype);
452 pr_info("Invalid crashpoint %s\n", crashpoint->name);
455 pr_info("Crash point %s of type %s registered\n",
456 crashpoint->name, cpoint_type);
458 pr_info("No crash points registered, enable through debugfs\n");
464 debugfs_remove_recursive(lkdtm_debugfs_root);
468 static void __exit lkdtm_module_exit(void)
470 debugfs_remove_recursive(lkdtm_debugfs_root);
472 /* Handle test-specific clean-up. */
474 lkdtm_usercopy_exit();
476 if (lkdtm_kprobe != NULL)
477 unregister_kprobe(lkdtm_kprobe);
479 kfree(lkdtm_kernel_info);
481 pr_info("Crash point unregistered\n");
484 module_init(lkdtm_module_init);
485 module_exit(lkdtm_module_exit);
487 MODULE_LICENSE("GPL");
488 MODULE_DESCRIPTION("Kernel crash testing module");