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gfs2: properly initial file_lock used for unlock.
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blobfec67188c4d28542f0b88f9ca9aca5fee5668e8d
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Kprobes-based tracing events
4 *
5 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 *
7 */
8 #define pr_fmt(fmt) "trace_kprobe: " fmt
9
10 #include <linux/module.h>
11 #include <linux/uaccess.h>
12 #include <linux/rculist.h>
13 #include <linux/error-injection.h>
14
15 #include "trace_kprobe_selftest.h"
16 #include "trace_probe.h"
17 #include "trace_probe_tmpl.h"
18
19 #define KPROBE_EVENT_SYSTEM "kprobes"
20 #define KRETPROBE_MAXACTIVE_MAX 4096
21
22 /**
23 * Kprobe event core functions
24 */
25 struct trace_kprobe {
26 struct list_head list;
27 struct kretprobe rp; /* Use rp.kp for kprobe use */
28 unsigned long __percpu *nhit;
29 const char *symbol; /* symbol name */
30 struct trace_probe tp;
31 };
32
33 #define SIZEOF_TRACE_KPROBE(n) \
34 (offsetof(struct trace_kprobe, tp.args) + \
35 (sizeof(struct probe_arg) * (n)))
36
37 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
38 {
39 return tk->rp.handler != NULL;
40 }
41
42 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
43 {
44 return tk->symbol ? tk->symbol : "unknown";
45 }
46
47 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
48 {
49 return tk->rp.kp.offset;
50 }
51
52 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
53 {
54 return !!(kprobe_gone(&tk->rp.kp));
55 }
56
57 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
58 struct module *mod)
59 {
60 int len = strlen(mod->name);
61 const char *name = trace_kprobe_symbol(tk);
62 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
63 }
64
65 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
66 {
67 char *p;
68 bool ret;
69
70 if (!tk->symbol)
71 return false;
72 p = strchr(tk->symbol, ':');
73 if (!p)
74 return true;
75 *p = '\0';
76 mutex_lock(&module_mutex);
77 ret = !!find_module(tk->symbol);
78 mutex_unlock(&module_mutex);
79 *p = ':';
80
81 return ret;
82 }
83
84 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
85 {
86 unsigned long nhit = 0;
87 int cpu;
88
89 for_each_possible_cpu(cpu)
90 nhit += *per_cpu_ptr(tk->nhit, cpu);
91
92 return nhit;
93 }
94
95 /* Return 0 if it fails to find the symbol address */
96 static nokprobe_inline
97 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
98 {
99 unsigned long addr;
100
101 if (tk->symbol) {
102 addr = (unsigned long)
103 kallsyms_lookup_name(trace_kprobe_symbol(tk));
104 if (addr)
105 addr += tk->rp.kp.offset;
106 } else {
107 addr = (unsigned long)tk->rp.kp.addr;
108 }
109 return addr;
110 }
111
112 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
113 {
114 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
115
116 return kprobe_on_func_entry(tk->rp.kp.addr,
117 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
118 tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
119 }
120
121 bool trace_kprobe_error_injectable(struct trace_event_call *call)
122 {
123 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
124
125 return within_error_injection_list(trace_kprobe_address(tk));
126 }
127
128 static int register_kprobe_event(struct trace_kprobe *tk);
129 static int unregister_kprobe_event(struct trace_kprobe *tk);
130
131 static DEFINE_MUTEX(probe_lock);
132 static LIST_HEAD(probe_list);
133
134 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
135 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
136 struct pt_regs *regs);
137
138 /*
139 * Allocate new trace_probe and initialize it (including kprobes).
140 */
141 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
142 const char *event,
143 void *addr,
144 const char *symbol,
145 unsigned long offs,
146 int maxactive,
147 int nargs, bool is_return)
148 {
149 struct trace_kprobe *tk;
150 int ret = -ENOMEM;
151
152 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
153 if (!tk)
154 return ERR_PTR(ret);
155
156 tk->nhit = alloc_percpu(unsigned long);
157 if (!tk->nhit)
158 goto error;
159
160 if (symbol) {
161 tk->symbol = kstrdup(symbol, GFP_KERNEL);
162 if (!tk->symbol)
163 goto error;
164 tk->rp.kp.symbol_name = tk->symbol;
165 tk->rp.kp.offset = offs;
166 } else
167 tk->rp.kp.addr = addr;
168
169 if (is_return)
170 tk->rp.handler = kretprobe_dispatcher;
171 else
172 tk->rp.kp.pre_handler = kprobe_dispatcher;
173
174 tk->rp.maxactive = maxactive;
175
176 if (!event || !is_good_name(event)) {
177 ret = -EINVAL;
178 goto error;
179 }
180
181 tk->tp.call.class = &tk->tp.class;
182 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
183 if (!tk->tp.call.name)
184 goto error;
185
186 if (!group || !is_good_name(group)) {
187 ret = -EINVAL;
188 goto error;
189 }
190
191 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
192 if (!tk->tp.class.system)
193 goto error;
194
195 INIT_LIST_HEAD(&tk->list);
196 INIT_LIST_HEAD(&tk->tp.files);
197 return tk;
198 error:
199 kfree(tk->tp.call.name);
200 kfree(tk->symbol);
201 free_percpu(tk->nhit);
202 kfree(tk);
203 return ERR_PTR(ret);
204 }
205
206 static void free_trace_kprobe(struct trace_kprobe *tk)
207 {
208 int i;
209
210 for (i = 0; i < tk->tp.nr_args; i++)
211 traceprobe_free_probe_arg(&tk->tp.args[i]);
212
213 kfree(tk->tp.call.class->system);
214 kfree(tk->tp.call.name);
215 kfree(tk->symbol);
216 free_percpu(tk->nhit);
217 kfree(tk);
218 }
219
220 static struct trace_kprobe *find_trace_kprobe(const char *event,
221 const char *group)
222 {
223 struct trace_kprobe *tk;
224
225 list_for_each_entry(tk, &probe_list, list)
226 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
227 strcmp(tk->tp.call.class->system, group) == 0)
228 return tk;
229 return NULL;
230 }
231
232 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
233 {
234 int ret = 0;
235
236 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
237 if (trace_kprobe_is_return(tk))
238 ret = enable_kretprobe(&tk->rp);
239 else
240 ret = enable_kprobe(&tk->rp.kp);
241 }
242
243 return ret;
244 }
245
246 /*
247 * Enable trace_probe
248 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
249 */
250 static int
251 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
252 {
253 struct event_file_link *link;
254 int ret = 0;
255
256 if (file) {
257 link = kmalloc(sizeof(*link), GFP_KERNEL);
258 if (!link) {
259 ret = -ENOMEM;
260 goto out;
261 }
262
263 link->file = file;
264 list_add_tail_rcu(&link->list, &tk->tp.files);
265
266 tk->tp.flags |= TP_FLAG_TRACE;
267 ret = __enable_trace_kprobe(tk);
268 if (ret) {
269 list_del_rcu(&link->list);
270 kfree(link);
271 tk->tp.flags &= ~TP_FLAG_TRACE;
272 }
273
274 } else {
275 tk->tp.flags |= TP_FLAG_PROFILE;
276 ret = __enable_trace_kprobe(tk);
277 if (ret)
278 tk->tp.flags &= ~TP_FLAG_PROFILE;
279 }
280 out:
281 return ret;
282 }
283
284 /*
285 * Disable trace_probe
286 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
287 */
288 static int
289 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
290 {
291 struct event_file_link *link = NULL;
292 int wait = 0;
293 int ret = 0;
294
295 if (file) {
296 link = find_event_file_link(&tk->tp, file);
297 if (!link) {
298 ret = -EINVAL;
299 goto out;
300 }
301
302 list_del_rcu(&link->list);
303 wait = 1;
304 if (!list_empty(&tk->tp.files))
305 goto out;
306
307 tk->tp.flags &= ~TP_FLAG_TRACE;
308 } else
309 tk->tp.flags &= ~TP_FLAG_PROFILE;
310
311 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
312 if (trace_kprobe_is_return(tk))
313 disable_kretprobe(&tk->rp);
314 else
315 disable_kprobe(&tk->rp.kp);
316 wait = 1;
317 }
318
319 /*
320 * if tk is not added to any list, it must be a local trace_kprobe
321 * created with perf_event_open. We don't need to wait for these
322 * trace_kprobes
323 */
324 if (list_empty(&tk->list))
325 wait = 0;
326 out:
327 if (wait) {
328 /*
329 * Synchronize with kprobe_trace_func/kretprobe_trace_func
330 * to ensure disabled (all running handlers are finished).
331 * This is not only for kfree(), but also the caller,
332 * trace_remove_event_call() supposes it for releasing
333 * event_call related objects, which will be accessed in
334 * the kprobe_trace_func/kretprobe_trace_func.
335 */
336 synchronize_sched();
337 kfree(link); /* Ignored if link == NULL */
338 }
339
340 return ret;
341 }
342
343 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
344 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
345 static bool within_notrace_func(struct trace_kprobe *tk)
346 {
347 unsigned long offset, size, addr;
348
349 addr = trace_kprobe_address(tk);
350 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
351 return false;
352
353 /* Get the entry address of the target function */
354 addr -= offset;
355
356 /*
357 * Since ftrace_location_range() does inclusive range check, we need
358 * to subtract 1 byte from the end address.
359 */
360 return !ftrace_location_range(addr, addr + size - 1);
361 }
362 #else
363 #define within_notrace_func(tk) (false)
364 #endif
365
366 /* Internal register function - just handle k*probes and flags */
367 static int __register_trace_kprobe(struct trace_kprobe *tk)
368 {
369 int i, ret;
370
371 if (trace_probe_is_registered(&tk->tp))
372 return -EINVAL;
373
374 if (within_notrace_func(tk)) {
375 pr_warn("Could not probe notrace function %s\n",
376 trace_kprobe_symbol(tk));
377 return -EINVAL;
378 }
379
380 for (i = 0; i < tk->tp.nr_args; i++) {
381 ret = traceprobe_update_arg(&tk->tp.args[i]);
382 if (ret)
383 return ret;
384 }
385
386 /* Set/clear disabled flag according to tp->flag */
387 if (trace_probe_is_enabled(&tk->tp))
388 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
389 else
390 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
391
392 if (trace_kprobe_is_return(tk))
393 ret = register_kretprobe(&tk->rp);
394 else
395 ret = register_kprobe(&tk->rp.kp);
396
397 if (ret == 0) {
398 tk->tp.flags |= TP_FLAG_REGISTERED;
399 } else if (ret == -EILSEQ) {
400 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
401 tk->rp.kp.addr);
402 ret = -EINVAL;
403 }
404 return ret;
405 }
406
407 /* Internal unregister function - just handle k*probes and flags */
408 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
409 {
410 if (trace_probe_is_registered(&tk->tp)) {
411 if (trace_kprobe_is_return(tk))
412 unregister_kretprobe(&tk->rp);
413 else
414 unregister_kprobe(&tk->rp.kp);
415 tk->tp.flags &= ~TP_FLAG_REGISTERED;
416 /* Cleanup kprobe for reuse */
417 if (tk->rp.kp.symbol_name)
418 tk->rp.kp.addr = NULL;
419 }
420 }
421
422 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
423 static int unregister_trace_kprobe(struct trace_kprobe *tk)
424 {
425 /* Enabled event can not be unregistered */
426 if (trace_probe_is_enabled(&tk->tp))
427 return -EBUSY;
428
429 /* Will fail if probe is being used by ftrace or perf */
430 if (unregister_kprobe_event(tk))
431 return -EBUSY;
432
433 __unregister_trace_kprobe(tk);
434 list_del(&tk->list);
435
436 return 0;
437 }
438
439 /* Register a trace_probe and probe_event */
440 static int register_trace_kprobe(struct trace_kprobe *tk)
441 {
442 struct trace_kprobe *old_tk;
443 int ret;
444
445 mutex_lock(&probe_lock);
446
447 /* Delete old (same name) event if exist */
448 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
449 tk->tp.call.class->system);
450 if (old_tk) {
451 ret = unregister_trace_kprobe(old_tk);
452 if (ret < 0)
453 goto end;
454 free_trace_kprobe(old_tk);
455 }
456
457 /* Register new event */
458 ret = register_kprobe_event(tk);
459 if (ret) {
460 pr_warn("Failed to register probe event(%d)\n", ret);
461 goto end;
462 }
463
464 /* Register k*probe */
465 ret = __register_trace_kprobe(tk);
466 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
467 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
468 ret = 0;
469 }
470
471 if (ret < 0)
472 unregister_kprobe_event(tk);
473 else
474 list_add_tail(&tk->list, &probe_list);
475
476 end:
477 mutex_unlock(&probe_lock);
478 return ret;
479 }
480
481 /* Module notifier call back, checking event on the module */
482 static int trace_kprobe_module_callback(struct notifier_block *nb,
483 unsigned long val, void *data)
484 {
485 struct module *mod = data;
486 struct trace_kprobe *tk;
487 int ret;
488
489 if (val != MODULE_STATE_COMING)
490 return NOTIFY_DONE;
491
492 /* Update probes on coming module */
493 mutex_lock(&probe_lock);
494 list_for_each_entry(tk, &probe_list, list) {
495 if (trace_kprobe_within_module(tk, mod)) {
496 /* Don't need to check busy - this should have gone. */
497 __unregister_trace_kprobe(tk);
498 ret = __register_trace_kprobe(tk);
499 if (ret)
500 pr_warn("Failed to re-register probe %s on %s: %d\n",
501 trace_event_name(&tk->tp.call),
502 mod->name, ret);
503 }
504 }
505 mutex_unlock(&probe_lock);
506
507 return NOTIFY_DONE;
508 }
509
510 static struct notifier_block trace_kprobe_module_nb = {
511 .notifier_call = trace_kprobe_module_callback,
512 .priority = 1 /* Invoked after kprobe module callback */
513 };
514
515 /* Convert certain expected symbols into '_' when generating event names */
516 static inline void sanitize_event_name(char *name)
517 {
518 while (*name++ != '\0')
519 if (*name == ':' || *name == '.')
520 *name = '_';
521 }
522
523 static int create_trace_kprobe(int argc, char **argv)
524 {
525 /*
526 * Argument syntax:
527 * - Add kprobe:
528 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
529 * - Add kretprobe:
530 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
531 * Fetch args:
532 * $retval : fetch return value
533 * $stack : fetch stack address
534 * $stackN : fetch Nth of stack (N:0-)
535 * $comm : fetch current task comm
536 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
537 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
538 * %REG : fetch register REG
539 * Dereferencing memory fetch:
540 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
541 * Alias name of args:
542 * NAME=FETCHARG : set NAME as alias of FETCHARG.
543 * Type of args:
544 * FETCHARG:TYPE : use TYPE instead of unsigned long.
545 */
546 struct trace_kprobe *tk;
547 int i, ret = 0;
548 bool is_return = false, is_delete = false;
549 char *symbol = NULL, *event = NULL, *group = NULL;
550 int maxactive = 0;
551 char *arg;
552 long offset = 0;
553 void *addr = NULL;
554 char buf[MAX_EVENT_NAME_LEN];
555 unsigned int flags = TPARG_FL_KERNEL;
556
557 /* argc must be >= 1 */
558 if (argv[0][0] == 'p')
559 is_return = false;
560 else if (argv[0][0] == 'r') {
561 is_return = true;
562 flags |= TPARG_FL_RETURN;
563 } else if (argv[0][0] == '-')
564 is_delete = true;
565 else {
566 pr_info("Probe definition must be started with 'p', 'r' or"
567 " '-'.\n");
568 return -EINVAL;
569 }
570
571 event = strchr(&argv[0][1], ':');
572 if (event) {
573 event[0] = '\0';
574 event++;
575 }
576 if (is_return && isdigit(argv[0][1])) {
577 ret = kstrtouint(&argv[0][1], 0, &maxactive);
578 if (ret) {
579 pr_info("Failed to parse maxactive.\n");
580 return ret;
581 }
582 /* kretprobes instances are iterated over via a list. The
583 * maximum should stay reasonable.
584 */
585 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
586 pr_info("Maxactive is too big (%d > %d).\n",
587 maxactive, KRETPROBE_MAXACTIVE_MAX);
588 return -E2BIG;
589 }
590 }
591
592 if (event) {
593 char *slash;
594
595 slash = strchr(event, '/');
596 if (slash) {
597 group = event;
598 event = slash + 1;
599 slash[0] = '\0';
600 if (strlen(group) == 0) {
601 pr_info("Group name is not specified\n");
602 return -EINVAL;
603 }
604 }
605 if (strlen(event) == 0) {
606 pr_info("Event name is not specified\n");
607 return -EINVAL;
608 }
609 }
610 if (!group)
611 group = KPROBE_EVENT_SYSTEM;
612
613 if (is_delete) {
614 if (!event) {
615 pr_info("Delete command needs an event name.\n");
616 return -EINVAL;
617 }
618 mutex_lock(&probe_lock);
619 tk = find_trace_kprobe(event, group);
620 if (!tk) {
621 mutex_unlock(&probe_lock);
622 pr_info("Event %s/%s doesn't exist.\n", group, event);
623 return -ENOENT;
624 }
625 /* delete an event */
626 ret = unregister_trace_kprobe(tk);
627 if (ret == 0)
628 free_trace_kprobe(tk);
629 mutex_unlock(&probe_lock);
630 return ret;
631 }
632
633 if (argc < 2) {
634 pr_info("Probe point is not specified.\n");
635 return -EINVAL;
636 }
637
638 /* try to parse an address. if that fails, try to read the
639 * input as a symbol. */
640 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
641 /* a symbol specified */
642 symbol = argv[1];
643 /* TODO: support .init module functions */
644 ret = traceprobe_split_symbol_offset(symbol, &offset);
645 if (ret || offset < 0 || offset > UINT_MAX) {
646 pr_info("Failed to parse either an address or a symbol.\n");
647 return ret;
648 }
649 if (kprobe_on_func_entry(NULL, symbol, offset))
650 flags |= TPARG_FL_FENTRY;
651 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
652 pr_info("Given offset is not valid for return probe.\n");
653 return -EINVAL;
654 }
655 }
656 argc -= 2; argv += 2;
657
658 /* setup a probe */
659 if (!event) {
660 /* Make a new event name */
661 if (symbol)
662 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
663 is_return ? 'r' : 'p', symbol, offset);
664 else
665 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
666 is_return ? 'r' : 'p', addr);
667 sanitize_event_name(buf);
668 event = buf;
669 }
670 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
671 argc, is_return);
672 if (IS_ERR(tk)) {
673 pr_info("Failed to allocate trace_probe.(%d)\n",
674 (int)PTR_ERR(tk));
675 return PTR_ERR(tk);
676 }
677
678 /* parse arguments */
679 ret = 0;
680 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
681 struct probe_arg *parg = &tk->tp.args[i];
682
683 /* Increment count for freeing args in error case */
684 tk->tp.nr_args++;
685
686 /* Parse argument name */
687 arg = strchr(argv[i], '=');
688 if (arg) {
689 *arg++ = '\0';
690 parg->name = kstrdup(argv[i], GFP_KERNEL);
691 } else {
692 arg = argv[i];
693 /* If argument name is omitted, set "argN" */
694 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
695 parg->name = kstrdup(buf, GFP_KERNEL);
696 }
697
698 if (!parg->name) {
699 pr_info("Failed to allocate argument[%d] name.\n", i);
700 ret = -ENOMEM;
701 goto error;
702 }
703
704 if (!is_good_name(parg->name)) {
705 pr_info("Invalid argument[%d] name: %s\n",
706 i, parg->name);
707 ret = -EINVAL;
708 goto error;
709 }
710
711 if (traceprobe_conflict_field_name(parg->name,
712 tk->tp.args, i)) {
713 pr_info("Argument[%d] name '%s' conflicts with "
714 "another field.\n", i, argv[i]);
715 ret = -EINVAL;
716 goto error;
717 }
718
719 /* Parse fetch argument */
720 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
721 flags);
722 if (ret) {
723 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
724 goto error;
725 }
726 }
727
728 ret = register_trace_kprobe(tk);
729 if (ret)
730 goto error;
731 return 0;
732
733 error:
734 free_trace_kprobe(tk);
735 return ret;
736 }
737
738 static int release_all_trace_kprobes(void)
739 {
740 struct trace_kprobe *tk;
741 int ret = 0;
742
743 mutex_lock(&probe_lock);
744 /* Ensure no probe is in use. */
745 list_for_each_entry(tk, &probe_list, list)
746 if (trace_probe_is_enabled(&tk->tp)) {
747 ret = -EBUSY;
748 goto end;
749 }
750 /* TODO: Use batch unregistration */
751 while (!list_empty(&probe_list)) {
752 tk = list_entry(probe_list.next, struct trace_kprobe, list);
753 ret = unregister_trace_kprobe(tk);
754 if (ret)
755 goto end;
756 free_trace_kprobe(tk);
757 }
758
759 end:
760 mutex_unlock(&probe_lock);
761
762 return ret;
763 }
764
765 /* Probes listing interfaces */
766 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
767 {
768 mutex_lock(&probe_lock);
769 return seq_list_start(&probe_list, *pos);
770 }
771
772 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
773 {
774 return seq_list_next(v, &probe_list, pos);
775 }
776
777 static void probes_seq_stop(struct seq_file *m, void *v)
778 {
779 mutex_unlock(&probe_lock);
780 }
781
782 static int probes_seq_show(struct seq_file *m, void *v)
783 {
784 struct trace_kprobe *tk = v;
785 int i;
786
787 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
788 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
789 trace_event_name(&tk->tp.call));
790
791 if (!tk->symbol)
792 seq_printf(m, " 0x%p", tk->rp.kp.addr);
793 else if (tk->rp.kp.offset)
794 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
795 tk->rp.kp.offset);
796 else
797 seq_printf(m, " %s", trace_kprobe_symbol(tk));
798
799 for (i = 0; i < tk->tp.nr_args; i++)
800 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
801 seq_putc(m, '\n');
802
803 return 0;
804 }
805
806 static const struct seq_operations probes_seq_op = {
807 .start = probes_seq_start,
808 .next = probes_seq_next,
809 .stop = probes_seq_stop,
810 .show = probes_seq_show
811 };
812
813 static int probes_open(struct inode *inode, struct file *file)
814 {
815 int ret;
816
817 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
818 ret = release_all_trace_kprobes();
819 if (ret < 0)
820 return ret;
821 }
822
823 return seq_open(file, &probes_seq_op);
824 }
825
826 static ssize_t probes_write(struct file *file, const char __user *buffer,
827 size_t count, loff_t *ppos)
828 {
829 return trace_parse_run_command(file, buffer, count, ppos,
830 create_trace_kprobe);
831 }
832
833 static const struct file_operations kprobe_events_ops = {
834 .owner = THIS_MODULE,
835 .open = probes_open,
836 .read = seq_read,
837 .llseek = seq_lseek,
838 .release = seq_release,
839 .write = probes_write,
840 };
841
842 /* Probes profiling interfaces */
843 static int probes_profile_seq_show(struct seq_file *m, void *v)
844 {
845 struct trace_kprobe *tk = v;
846
847 seq_printf(m, " %-44s %15lu %15lu\n",
848 trace_event_name(&tk->tp.call),
849 trace_kprobe_nhit(tk),
850 tk->rp.kp.nmissed);
851
852 return 0;
853 }
854
855 static const struct seq_operations profile_seq_op = {
856 .start = probes_seq_start,
857 .next = probes_seq_next,
858 .stop = probes_seq_stop,
859 .show = probes_profile_seq_show
860 };
861
862 static int profile_open(struct inode *inode, struct file *file)
863 {
864 return seq_open(file, &profile_seq_op);
865 }
866
867 static const struct file_operations kprobe_profile_ops = {
868 .owner = THIS_MODULE,
869 .open = profile_open,
870 .read = seq_read,
871 .llseek = seq_lseek,
872 .release = seq_release,
873 };
874
875 /* Kprobe specific fetch functions */
876
877 /* Return the length of string -- including null terminal byte */
878 static nokprobe_inline int
879 fetch_store_strlen(unsigned long addr)
880 {
881 mm_segment_t old_fs;
882 int ret, len = 0;
883 u8 c;
884
885 old_fs = get_fs();
886 set_fs(KERNEL_DS);
887 pagefault_disable();
888
889 do {
890 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
891 len++;
892 } while (c && ret == 0 && len < MAX_STRING_SIZE);
893
894 pagefault_enable();
895 set_fs(old_fs);
896
897 return (ret < 0) ? ret : len;
898 }
899
900 /*
901 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
902 * length and relative data location.
903 */
904 static nokprobe_inline int
905 fetch_store_string(unsigned long addr, void *dest, void *base)
906 {
907 int maxlen = get_loc_len(*(u32 *)dest);
908 u8 *dst = get_loc_data(dest, base);
909 long ret;
910
911 if (unlikely(!maxlen))
912 return -ENOMEM;
913 /*
914 * Try to get string again, since the string can be changed while
915 * probing.
916 */
917 ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
918
919 if (ret >= 0)
920 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
921 return ret;
922 }
923
924 static nokprobe_inline int
925 probe_mem_read(void *dest, void *src, size_t size)
926 {
927 return probe_kernel_read(dest, src, size);
928 }
929
930 /* Note that we don't verify it, since the code does not come from user space */
931 static int
932 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
933 void *base)
934 {
935 unsigned long val;
936
937 retry:
938 /* 1st stage: get value from context */
939 switch (code->op) {
940 case FETCH_OP_REG:
941 val = regs_get_register(regs, code->param);
942 break;
943 case FETCH_OP_STACK:
944 val = regs_get_kernel_stack_nth(regs, code->param);
945 break;
946 case FETCH_OP_STACKP:
947 val = kernel_stack_pointer(regs);
948 break;
949 case FETCH_OP_RETVAL:
950 val = regs_return_value(regs);
951 break;
952 case FETCH_OP_IMM:
953 val = code->immediate;
954 break;
955 case FETCH_OP_COMM:
956 val = (unsigned long)current->comm;
957 break;
958 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
959 case FETCH_OP_ARG:
960 val = regs_get_kernel_argument(regs, code->param);
961 break;
962 #endif
963 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
964 code++;
965 goto retry;
966 default:
967 return -EILSEQ;
968 }
969 code++;
970
971 return process_fetch_insn_bottom(code, val, dest, base);
972 }
973 NOKPROBE_SYMBOL(process_fetch_insn)
974
975 /* Kprobe handler */
976 static nokprobe_inline void
977 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
978 struct trace_event_file *trace_file)
979 {
980 struct kprobe_trace_entry_head *entry;
981 struct ring_buffer_event *event;
982 struct ring_buffer *buffer;
983 int size, dsize, pc;
984 unsigned long irq_flags;
985 struct trace_event_call *call = &tk->tp.call;
986
987 WARN_ON(call != trace_file->event_call);
988
989 if (trace_trigger_soft_disabled(trace_file))
990 return;
991
992 local_save_flags(irq_flags);
993 pc = preempt_count();
994
995 dsize = __get_data_size(&tk->tp, regs);
996 size = sizeof(*entry) + tk->tp.size + dsize;
997
998 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
999 call->event.type,
1000 size, irq_flags, pc);
1001 if (!event)
1002 return;
1003
1004 entry = ring_buffer_event_data(event);
1005 entry->ip = (unsigned long)tk->rp.kp.addr;
1006 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1007
1008 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1009 entry, irq_flags, pc, regs);
1010 }
1011
1012 static void
1013 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1014 {
1015 struct event_file_link *link;
1016
1017 list_for_each_entry_rcu(link, &tk->tp.files, list)
1018 __kprobe_trace_func(tk, regs, link->file);
1019 }
1020 NOKPROBE_SYMBOL(kprobe_trace_func);
1021
1022 /* Kretprobe handler */
1023 static nokprobe_inline void
1024 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1025 struct pt_regs *regs,
1026 struct trace_event_file *trace_file)
1027 {
1028 struct kretprobe_trace_entry_head *entry;
1029 struct ring_buffer_event *event;
1030 struct ring_buffer *buffer;
1031 int size, pc, dsize;
1032 unsigned long irq_flags;
1033 struct trace_event_call *call = &tk->tp.call;
1034
1035 WARN_ON(call != trace_file->event_call);
1036
1037 if (trace_trigger_soft_disabled(trace_file))
1038 return;
1039
1040 local_save_flags(irq_flags);
1041 pc = preempt_count();
1042
1043 dsize = __get_data_size(&tk->tp, regs);
1044 size = sizeof(*entry) + tk->tp.size + dsize;
1045
1046 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1047 call->event.type,
1048 size, irq_flags, pc);
1049 if (!event)
1050 return;
1051
1052 entry = ring_buffer_event_data(event);
1053 entry->func = (unsigned long)tk->rp.kp.addr;
1054 entry->ret_ip = (unsigned long)ri->ret_addr;
1055 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1056
1057 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1058 entry, irq_flags, pc, regs);
1059 }
1060
1061 static void
1062 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1063 struct pt_regs *regs)
1064 {
1065 struct event_file_link *link;
1066
1067 list_for_each_entry_rcu(link, &tk->tp.files, list)
1068 __kretprobe_trace_func(tk, ri, regs, link->file);
1069 }
1070 NOKPROBE_SYMBOL(kretprobe_trace_func);
1071
1072 /* Event entry printers */
1073 static enum print_line_t
1074 print_kprobe_event(struct trace_iterator *iter, int flags,
1075 struct trace_event *event)
1076 {
1077 struct kprobe_trace_entry_head *field;
1078 struct trace_seq *s = &iter->seq;
1079 struct trace_probe *tp;
1080
1081 field = (struct kprobe_trace_entry_head *)iter->ent;
1082 tp = container_of(event, struct trace_probe, call.event);
1083
1084 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1085
1086 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1087 goto out;
1088
1089 trace_seq_putc(s, ')');
1090
1091 if (print_probe_args(s, tp->args, tp->nr_args,
1092 (u8 *)&field[1], field) < 0)
1093 goto out;
1094
1095 trace_seq_putc(s, '\n');
1096 out:
1097 return trace_handle_return(s);
1098 }
1099
1100 static enum print_line_t
1101 print_kretprobe_event(struct trace_iterator *iter, int flags,
1102 struct trace_event *event)
1103 {
1104 struct kretprobe_trace_entry_head *field;
1105 struct trace_seq *s = &iter->seq;
1106 struct trace_probe *tp;
1107
1108 field = (struct kretprobe_trace_entry_head *)iter->ent;
1109 tp = container_of(event, struct trace_probe, call.event);
1110
1111 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1112
1113 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1114 goto out;
1115
1116 trace_seq_puts(s, " <- ");
1117
1118 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1119 goto out;
1120
1121 trace_seq_putc(s, ')');
1122
1123 if (print_probe_args(s, tp->args, tp->nr_args,
1124 (u8 *)&field[1], field) < 0)
1125 goto out;
1126
1127 trace_seq_putc(s, '\n');
1128
1129 out:
1130 return trace_handle_return(s);
1131 }
1132
1133
1134 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1135 {
1136 int ret;
1137 struct kprobe_trace_entry_head field;
1138 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1139
1140 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1141
1142 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1143 }
1144
1145 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1146 {
1147 int ret;
1148 struct kretprobe_trace_entry_head field;
1149 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1150
1151 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1152 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1153
1154 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1155 }
1156
1157 #ifdef CONFIG_PERF_EVENTS
1158
1159 /* Kprobe profile handler */
1160 static int
1161 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1162 {
1163 struct trace_event_call *call = &tk->tp.call;
1164 struct kprobe_trace_entry_head *entry;
1165 struct hlist_head *head;
1166 int size, __size, dsize;
1167 int rctx;
1168
1169 if (bpf_prog_array_valid(call)) {
1170 unsigned long orig_ip = instruction_pointer(regs);
1171 int ret;
1172
1173 ret = trace_call_bpf(call, regs);
1174
1175 /*
1176 * We need to check and see if we modified the pc of the
1177 * pt_regs, and if so return 1 so that we don't do the
1178 * single stepping.
1179 */
1180 if (orig_ip != instruction_pointer(regs))
1181 return 1;
1182 if (!ret)
1183 return 0;
1184 }
1185
1186 head = this_cpu_ptr(call->perf_events);
1187 if (hlist_empty(head))
1188 return 0;
1189
1190 dsize = __get_data_size(&tk->tp, regs);
1191 __size = sizeof(*entry) + tk->tp.size + dsize;
1192 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1193 size -= sizeof(u32);
1194
1195 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1196 if (!entry)
1197 return 0;
1198
1199 entry->ip = (unsigned long)tk->rp.kp.addr;
1200 memset(&entry[1], 0, dsize);
1201 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1202 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1203 head, NULL);
1204 return 0;
1205 }
1206 NOKPROBE_SYMBOL(kprobe_perf_func);
1207
1208 /* Kretprobe profile handler */
1209 static void
1210 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1211 struct pt_regs *regs)
1212 {
1213 struct trace_event_call *call = &tk->tp.call;
1214 struct kretprobe_trace_entry_head *entry;
1215 struct hlist_head *head;
1216 int size, __size, dsize;
1217 int rctx;
1218
1219 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1220 return;
1221
1222 head = this_cpu_ptr(call->perf_events);
1223 if (hlist_empty(head))
1224 return;
1225
1226 dsize = __get_data_size(&tk->tp, regs);
1227 __size = sizeof(*entry) + tk->tp.size + dsize;
1228 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1229 size -= sizeof(u32);
1230
1231 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1232 if (!entry)
1233 return;
1234
1235 entry->func = (unsigned long)tk->rp.kp.addr;
1236 entry->ret_ip = (unsigned long)ri->ret_addr;
1237 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1238 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1239 head, NULL);
1240 }
1241 NOKPROBE_SYMBOL(kretprobe_perf_func);
1242
1243 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1244 const char **symbol, u64 *probe_offset,
1245 u64 *probe_addr, bool perf_type_tracepoint)
1246 {
1247 const char *pevent = trace_event_name(event->tp_event);
1248 const char *group = event->tp_event->class->system;
1249 struct trace_kprobe *tk;
1250
1251 if (perf_type_tracepoint)
1252 tk = find_trace_kprobe(pevent, group);
1253 else
1254 tk = event->tp_event->data;
1255 if (!tk)
1256 return -EINVAL;
1257
1258 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1259 : BPF_FD_TYPE_KPROBE;
1260 if (tk->symbol) {
1261 *symbol = tk->symbol;
1262 *probe_offset = tk->rp.kp.offset;
1263 *probe_addr = 0;
1264 } else {
1265 *symbol = NULL;
1266 *probe_offset = 0;
1267 *probe_addr = (unsigned long)tk->rp.kp.addr;
1268 }
1269 return 0;
1270 }
1271 #endif /* CONFIG_PERF_EVENTS */
1272
1273 /*
1274 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1275 *
1276 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1277 * lockless, but we can't race with this __init function.
1278 */
1279 static int kprobe_register(struct trace_event_call *event,
1280 enum trace_reg type, void *data)
1281 {
1282 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1283 struct trace_event_file *file = data;
1284
1285 switch (type) {
1286 case TRACE_REG_REGISTER:
1287 return enable_trace_kprobe(tk, file);
1288 case TRACE_REG_UNREGISTER:
1289 return disable_trace_kprobe(tk, file);
1290
1291 #ifdef CONFIG_PERF_EVENTS
1292 case TRACE_REG_PERF_REGISTER:
1293 return enable_trace_kprobe(tk, NULL);
1294 case TRACE_REG_PERF_UNREGISTER:
1295 return disable_trace_kprobe(tk, NULL);
1296 case TRACE_REG_PERF_OPEN:
1297 case TRACE_REG_PERF_CLOSE:
1298 case TRACE_REG_PERF_ADD:
1299 case TRACE_REG_PERF_DEL:
1300 return 0;
1301 #endif
1302 }
1303 return 0;
1304 }
1305
1306 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1307 {
1308 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1309 int ret = 0;
1310
1311 raw_cpu_inc(*tk->nhit);
1312
1313 if (tk->tp.flags & TP_FLAG_TRACE)
1314 kprobe_trace_func(tk, regs);
1315 #ifdef CONFIG_PERF_EVENTS
1316 if (tk->tp.flags & TP_FLAG_PROFILE)
1317 ret = kprobe_perf_func(tk, regs);
1318 #endif
1319 return ret;
1320 }
1321 NOKPROBE_SYMBOL(kprobe_dispatcher);
1322
1323 static int
1324 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1325 {
1326 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1327
1328 raw_cpu_inc(*tk->nhit);
1329
1330 if (tk->tp.flags & TP_FLAG_TRACE)
1331 kretprobe_trace_func(tk, ri, regs);
1332 #ifdef CONFIG_PERF_EVENTS
1333 if (tk->tp.flags & TP_FLAG_PROFILE)
1334 kretprobe_perf_func(tk, ri, regs);
1335 #endif
1336 return 0; /* We don't tweek kernel, so just return 0 */
1337 }
1338 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1339
1340 static struct trace_event_functions kretprobe_funcs = {
1341 .trace = print_kretprobe_event
1342 };
1343
1344 static struct trace_event_functions kprobe_funcs = {
1345 .trace = print_kprobe_event
1346 };
1347
1348 static inline void init_trace_event_call(struct trace_kprobe *tk,
1349 struct trace_event_call *call)
1350 {
1351 INIT_LIST_HEAD(&call->class->fields);
1352 if (trace_kprobe_is_return(tk)) {
1353 call->event.funcs = &kretprobe_funcs;
1354 call->class->define_fields = kretprobe_event_define_fields;
1355 } else {
1356 call->event.funcs = &kprobe_funcs;
1357 call->class->define_fields = kprobe_event_define_fields;
1358 }
1359
1360 call->flags = TRACE_EVENT_FL_KPROBE;
1361 call->class->reg = kprobe_register;
1362 call->data = tk;
1363 }
1364
1365 static int register_kprobe_event(struct trace_kprobe *tk)
1366 {
1367 struct trace_event_call *call = &tk->tp.call;
1368 int ret = 0;
1369
1370 init_trace_event_call(tk, call);
1371
1372 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1373 return -ENOMEM;
1374 ret = register_trace_event(&call->event);
1375 if (!ret) {
1376 kfree(call->print_fmt);
1377 return -ENODEV;
1378 }
1379 ret = trace_add_event_call(call);
1380 if (ret) {
1381 pr_info("Failed to register kprobe event: %s\n",
1382 trace_event_name(call));
1383 kfree(call->print_fmt);
1384 unregister_trace_event(&call->event);
1385 }
1386 return ret;
1387 }
1388
1389 static int unregister_kprobe_event(struct trace_kprobe *tk)
1390 {
1391 int ret;
1392
1393 /* tp->event is unregistered in trace_remove_event_call() */
1394 ret = trace_remove_event_call(&tk->tp.call);
1395 if (!ret)
1396 kfree(tk->tp.call.print_fmt);
1397 return ret;
1398 }
1399
1400 #ifdef CONFIG_PERF_EVENTS
1401 /* create a trace_kprobe, but don't add it to global lists */
1402 struct trace_event_call *
1403 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1404 bool is_return)
1405 {
1406 struct trace_kprobe *tk;
1407 int ret;
1408 char *event;
1409
1410 /*
1411 * local trace_kprobes are not added to probe_list, so they are never
1412 * searched in find_trace_kprobe(). Therefore, there is no concern of
1413 * duplicated name here.
1414 */
1415 event = func ? func : "DUMMY_EVENT";
1416
1417 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1418 offs, 0 /* maxactive */, 0 /* nargs */,
1419 is_return);
1420
1421 if (IS_ERR(tk)) {
1422 pr_info("Failed to allocate trace_probe.(%d)\n",
1423 (int)PTR_ERR(tk));
1424 return ERR_CAST(tk);
1425 }
1426
1427 init_trace_event_call(tk, &tk->tp.call);
1428
1429 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1430 ret = -ENOMEM;
1431 goto error;
1432 }
1433
1434 ret = __register_trace_kprobe(tk);
1435 if (ret < 0) {
1436 kfree(tk->tp.call.print_fmt);
1437 goto error;
1438 }
1439
1440 return &tk->tp.call;
1441 error:
1442 free_trace_kprobe(tk);
1443 return ERR_PTR(ret);
1444 }
1445
1446 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1447 {
1448 struct trace_kprobe *tk;
1449
1450 tk = container_of(event_call, struct trace_kprobe, tp.call);
1451
1452 if (trace_probe_is_enabled(&tk->tp)) {
1453 WARN_ON(1);
1454 return;
1455 }
1456
1457 __unregister_trace_kprobe(tk);
1458
1459 kfree(tk->tp.call.print_fmt);
1460 free_trace_kprobe(tk);
1461 }
1462 #endif /* CONFIG_PERF_EVENTS */
1463
1464 /* Make a tracefs interface for controlling probe points */
1465 static __init int init_kprobe_trace(void)
1466 {
1467 struct dentry *d_tracer;
1468 struct dentry *entry;
1469
1470 if (register_module_notifier(&trace_kprobe_module_nb))
1471 return -EINVAL;
1472
1473 d_tracer = tracing_init_dentry();
1474 if (IS_ERR(d_tracer))
1475 return 0;
1476
1477 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1478 NULL, &kprobe_events_ops);
1479
1480 /* Event list interface */
1481 if (!entry)
1482 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1483
1484 /* Profile interface */
1485 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1486 NULL, &kprobe_profile_ops);
1487
1488 if (!entry)
1489 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1490 return 0;
1491 }
1492 fs_initcall(init_kprobe_trace);
1493
1494
1495 #ifdef CONFIG_FTRACE_STARTUP_TEST
1496 static __init struct trace_event_file *
1497 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1498 {
1499 struct trace_event_file *file;
1500
1501 list_for_each_entry(file, &tr->events, list)
1502 if (file->event_call == &tk->tp.call)
1503 return file;
1504
1505 return NULL;
1506 }
1507
1508 /*
1509 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1510 * stage, we can do this lockless.
1511 */
1512 static __init int kprobe_trace_self_tests_init(void)
1513 {
1514 int ret, warn = 0;
1515 int (*target)(int, int, int, int, int, int);
1516 struct trace_kprobe *tk;
1517 struct trace_event_file *file;
1518
1519 if (tracing_is_disabled())
1520 return -ENODEV;
1521
1522 target = kprobe_trace_selftest_target;
1523
1524 pr_info("Testing kprobe tracing: ");
1525
1526 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1527 "$stack $stack0 +0($stack)",
1528 create_trace_kprobe);
1529 if (WARN_ON_ONCE(ret)) {
1530 pr_warn("error on probing function entry.\n");
1531 warn++;
1532 } else {
1533 /* Enable trace point */
1534 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1535 if (WARN_ON_ONCE(tk == NULL)) {
1536 pr_warn("error on getting new probe.\n");
1537 warn++;
1538 } else {
1539 file = find_trace_probe_file(tk, top_trace_array());
1540 if (WARN_ON_ONCE(file == NULL)) {
1541 pr_warn("error on getting probe file.\n");
1542 warn++;
1543 } else
1544 enable_trace_kprobe(tk, file);
1545 }
1546 }
1547
1548 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1549 "$retval", create_trace_kprobe);
1550 if (WARN_ON_ONCE(ret)) {
1551 pr_warn("error on probing function return.\n");
1552 warn++;
1553 } else {
1554 /* Enable trace point */
1555 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1556 if (WARN_ON_ONCE(tk == NULL)) {
1557 pr_warn("error on getting 2nd new probe.\n");
1558 warn++;
1559 } else {
1560 file = find_trace_probe_file(tk, top_trace_array());
1561 if (WARN_ON_ONCE(file == NULL)) {
1562 pr_warn("error on getting probe file.\n");
1563 warn++;
1564 } else
1565 enable_trace_kprobe(tk, file);
1566 }
1567 }
1568
1569 if (warn)
1570 goto end;
1571
1572 ret = target(1, 2, 3, 4, 5, 6);
1573
1574 /*
1575 * Not expecting an error here, the check is only to prevent the
1576 * optimizer from removing the call to target() as otherwise there
1577 * are no side-effects and the call is never performed.
1578 */
1579 if (ret != 21)
1580 warn++;
1581
1582 /* Disable trace points before removing it */
1583 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1584 if (WARN_ON_ONCE(tk == NULL)) {
1585 pr_warn("error on getting test probe.\n");
1586 warn++;
1587 } else {
1588 if (trace_kprobe_nhit(tk) != 1) {
1589 pr_warn("incorrect number of testprobe hits\n");
1590 warn++;
1591 }
1592
1593 file = find_trace_probe_file(tk, top_trace_array());
1594 if (WARN_ON_ONCE(file == NULL)) {
1595 pr_warn("error on getting probe file.\n");
1596 warn++;
1597 } else
1598 disable_trace_kprobe(tk, file);
1599 }
1600
1601 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1602 if (WARN_ON_ONCE(tk == NULL)) {
1603 pr_warn("error on getting 2nd test probe.\n");
1604 warn++;
1605 } else {
1606 if (trace_kprobe_nhit(tk) != 1) {
1607 pr_warn("incorrect number of testprobe2 hits\n");
1608 warn++;
1609 }
1610
1611 file = find_trace_probe_file(tk, top_trace_array());
1612 if (WARN_ON_ONCE(file == NULL)) {
1613 pr_warn("error on getting probe file.\n");
1614 warn++;
1615 } else
1616 disable_trace_kprobe(tk, file);
1617 }
1618
1619 ret = trace_run_command("-:testprobe", create_trace_kprobe);
1620 if (WARN_ON_ONCE(ret)) {
1621 pr_warn("error on deleting a probe.\n");
1622 warn++;
1623 }
1624
1625 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1626 if (WARN_ON_ONCE(ret)) {
1627 pr_warn("error on deleting a probe.\n");
1628 warn++;
1629 }
1630
1631 end:
1632 release_all_trace_kprobes();
1633 /*
1634 * Wait for the optimizer work to finish. Otherwise it might fiddle
1635 * with probes in already freed __init text.
1636 */
1637 wait_for_kprobe_optimizer();
1638 if (warn)
1639 pr_cont("NG: Some tests are failed. Please check them.\n");
1640 else
1641 pr_cont("OK\n");
1642 return 0;
1643 }
1644
1645 late_initcall(kprobe_trace_self_tests_init);
1646
1647 #endif
Linux with added FPC-III support