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Merge tag 'for-linus-20190706' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / kernel / trace / trace_kprobe.c
blob7d736248a070b2f633349856345e2013d4a3cd34
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_dynevent.h"
16 #include "trace_kprobe_selftest.h"
17 #include "trace_probe.h"
18 #include "trace_probe_tmpl.h"
19
20 #define KPROBE_EVENT_SYSTEM "kprobes"
21 #define KRETPROBE_MAXACTIVE_MAX 4096
22
23 static int trace_kprobe_create(int argc, const char **argv);
24 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
25 static int trace_kprobe_release(struct dyn_event *ev);
26 static bool trace_kprobe_is_busy(struct dyn_event *ev);
27 static bool trace_kprobe_match(const char *system, const char *event,
28 struct dyn_event *ev);
29
30 static struct dyn_event_operations trace_kprobe_ops = {
31 .create = trace_kprobe_create,
32 .show = trace_kprobe_show,
33 .is_busy = trace_kprobe_is_busy,
34 .free = trace_kprobe_release,
35 .match = trace_kprobe_match,
36 };
37
38 /*
39 * Kprobe event core functions
40 */
41 struct trace_kprobe {
42 struct dyn_event devent;
43 struct kretprobe rp; /* Use rp.kp for kprobe use */
44 unsigned long __percpu *nhit;
45 const char *symbol; /* symbol name */
46 struct trace_probe tp;
47 };
48
49 static bool is_trace_kprobe(struct dyn_event *ev)
50 {
51 return ev->ops == &trace_kprobe_ops;
52 }
53
54 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
55 {
56 return container_of(ev, struct trace_kprobe, devent);
57 }
58
59 /**
60 * for_each_trace_kprobe - iterate over the trace_kprobe list
61 * @pos: the struct trace_kprobe * for each entry
62 * @dpos: the struct dyn_event * to use as a loop cursor
63 */
64 #define for_each_trace_kprobe(pos, dpos) \
65 for_each_dyn_event(dpos) \
66 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
67
68 #define SIZEOF_TRACE_KPROBE(n) \
69 (offsetof(struct trace_kprobe, tp.args) + \
70 (sizeof(struct probe_arg) * (n)))
71
72 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
73 {
74 return tk->rp.handler != NULL;
75 }
76
77 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
78 {
79 return tk->symbol ? tk->symbol : "unknown";
80 }
81
82 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
83 {
84 return tk->rp.kp.offset;
85 }
86
87 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
88 {
89 return !!(kprobe_gone(&tk->rp.kp));
90 }
91
92 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
93 struct module *mod)
94 {
95 int len = strlen(mod->name);
96 const char *name = trace_kprobe_symbol(tk);
97 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
98 }
99
100 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
101 {
102 char *p;
103 bool ret;
104
105 if (!tk->symbol)
106 return false;
107 p = strchr(tk->symbol, ':');
108 if (!p)
109 return true;
110 *p = '\0';
111 mutex_lock(&module_mutex);
112 ret = !!find_module(tk->symbol);
113 mutex_unlock(&module_mutex);
114 *p = ':';
115
116 return ret;
117 }
118
119 static bool trace_kprobe_is_busy(struct dyn_event *ev)
120 {
121 struct trace_kprobe *tk = to_trace_kprobe(ev);
122
123 return trace_probe_is_enabled(&tk->tp);
124 }
125
126 static bool trace_kprobe_match(const char *system, const char *event,
127 struct dyn_event *ev)
128 {
129 struct trace_kprobe *tk = to_trace_kprobe(ev);
130
131 return strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
132 (!system || strcmp(tk->tp.call.class->system, system) == 0);
133 }
134
135 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
136 {
137 unsigned long nhit = 0;
138 int cpu;
139
140 for_each_possible_cpu(cpu)
141 nhit += *per_cpu_ptr(tk->nhit, cpu);
142
143 return nhit;
144 }
145
146 /* Return 0 if it fails to find the symbol address */
147 static nokprobe_inline
148 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
149 {
150 unsigned long addr;
151
152 if (tk->symbol) {
153 addr = (unsigned long)
154 kallsyms_lookup_name(trace_kprobe_symbol(tk));
155 if (addr)
156 addr += tk->rp.kp.offset;
157 } else {
158 addr = (unsigned long)tk->rp.kp.addr;
159 }
160 return addr;
161 }
162
163 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
164 {
165 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
166
167 return kprobe_on_func_entry(tk->rp.kp.addr,
168 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
169 tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
170 }
171
172 bool trace_kprobe_error_injectable(struct trace_event_call *call)
173 {
174 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
175
176 return within_error_injection_list(trace_kprobe_address(tk));
177 }
178
179 static int register_kprobe_event(struct trace_kprobe *tk);
180 static int unregister_kprobe_event(struct trace_kprobe *tk);
181
182 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
183 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
184 struct pt_regs *regs);
185
186 /*
187 * Allocate new trace_probe and initialize it (including kprobes).
188 */
189 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
190 const char *event,
191 void *addr,
192 const char *symbol,
193 unsigned long offs,
194 int maxactive,
195 int nargs, bool is_return)
196 {
197 struct trace_kprobe *tk;
198 int ret = -ENOMEM;
199
200 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
201 if (!tk)
202 return ERR_PTR(ret);
203
204 tk->nhit = alloc_percpu(unsigned long);
205 if (!tk->nhit)
206 goto error;
207
208 if (symbol) {
209 tk->symbol = kstrdup(symbol, GFP_KERNEL);
210 if (!tk->symbol)
211 goto error;
212 tk->rp.kp.symbol_name = tk->symbol;
213 tk->rp.kp.offset = offs;
214 } else
215 tk->rp.kp.addr = addr;
216
217 if (is_return)
218 tk->rp.handler = kretprobe_dispatcher;
219 else
220 tk->rp.kp.pre_handler = kprobe_dispatcher;
221
222 tk->rp.maxactive = maxactive;
223
224 if (!event || !group) {
225 ret = -EINVAL;
226 goto error;
227 }
228
229 tk->tp.call.class = &tk->tp.class;
230 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
231 if (!tk->tp.call.name)
232 goto error;
233
234 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
235 if (!tk->tp.class.system)
236 goto error;
237
238 dyn_event_init(&tk->devent, &trace_kprobe_ops);
239 INIT_LIST_HEAD(&tk->tp.files);
240 return tk;
241 error:
242 kfree(tk->tp.call.name);
243 kfree(tk->symbol);
244 free_percpu(tk->nhit);
245 kfree(tk);
246 return ERR_PTR(ret);
247 }
248
249 static void free_trace_kprobe(struct trace_kprobe *tk)
250 {
251 int i;
252
253 if (!tk)
254 return;
255
256 for (i = 0; i < tk->tp.nr_args; i++)
257 traceprobe_free_probe_arg(&tk->tp.args[i]);
258
259 kfree(tk->tp.call.class->system);
260 kfree(tk->tp.call.name);
261 kfree(tk->symbol);
262 free_percpu(tk->nhit);
263 kfree(tk);
264 }
265
266 static struct trace_kprobe *find_trace_kprobe(const char *event,
267 const char *group)
268 {
269 struct dyn_event *pos;
270 struct trace_kprobe *tk;
271
272 for_each_trace_kprobe(tk, pos)
273 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
274 strcmp(tk->tp.call.class->system, group) == 0)
275 return tk;
276 return NULL;
277 }
278
279 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
280 {
281 int ret = 0;
282
283 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
284 if (trace_kprobe_is_return(tk))
285 ret = enable_kretprobe(&tk->rp);
286 else
287 ret = enable_kprobe(&tk->rp.kp);
288 }
289
290 return ret;
291 }
292
293 /*
294 * Enable trace_probe
295 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
296 */
297 static int
298 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
299 {
300 struct event_file_link *link;
301 int ret = 0;
302
303 if (file) {
304 link = kmalloc(sizeof(*link), GFP_KERNEL);
305 if (!link) {
306 ret = -ENOMEM;
307 goto out;
308 }
309
310 link->file = file;
311 list_add_tail_rcu(&link->list, &tk->tp.files);
312
313 tk->tp.flags |= TP_FLAG_TRACE;
314 ret = __enable_trace_kprobe(tk);
315 if (ret) {
316 list_del_rcu(&link->list);
317 kfree(link);
318 tk->tp.flags &= ~TP_FLAG_TRACE;
319 }
320
321 } else {
322 tk->tp.flags |= TP_FLAG_PROFILE;
323 ret = __enable_trace_kprobe(tk);
324 if (ret)
325 tk->tp.flags &= ~TP_FLAG_PROFILE;
326 }
327 out:
328 return ret;
329 }
330
331 /*
332 * Disable trace_probe
333 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
334 */
335 static int
336 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
337 {
338 struct event_file_link *link = NULL;
339 int wait = 0;
340 int ret = 0;
341
342 if (file) {
343 link = find_event_file_link(&tk->tp, file);
344 if (!link) {
345 ret = -EINVAL;
346 goto out;
347 }
348
349 list_del_rcu(&link->list);
350 wait = 1;
351 if (!list_empty(&tk->tp.files))
352 goto out;
353
354 tk->tp.flags &= ~TP_FLAG_TRACE;
355 } else
356 tk->tp.flags &= ~TP_FLAG_PROFILE;
357
358 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
359 if (trace_kprobe_is_return(tk))
360 disable_kretprobe(&tk->rp);
361 else
362 disable_kprobe(&tk->rp.kp);
363 wait = 1;
364 }
365
366 /*
367 * if tk is not added to any list, it must be a local trace_kprobe
368 * created with perf_event_open. We don't need to wait for these
369 * trace_kprobes
370 */
371 if (list_empty(&tk->devent.list))
372 wait = 0;
373 out:
374 if (wait) {
375 /*
376 * Synchronize with kprobe_trace_func/kretprobe_trace_func
377 * to ensure disabled (all running handlers are finished).
378 * This is not only for kfree(), but also the caller,
379 * trace_remove_event_call() supposes it for releasing
380 * event_call related objects, which will be accessed in
381 * the kprobe_trace_func/kretprobe_trace_func.
382 */
383 synchronize_rcu();
384 kfree(link); /* Ignored if link == NULL */
385 }
386
387 return ret;
388 }
389
390 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
391 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
392 static bool within_notrace_func(struct trace_kprobe *tk)
393 {
394 unsigned long offset, size, addr;
395
396 addr = trace_kprobe_address(tk);
397 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
398 return false;
399
400 /* Get the entry address of the target function */
401 addr -= offset;
402
403 /*
404 * Since ftrace_location_range() does inclusive range check, we need
405 * to subtract 1 byte from the end address.
406 */
407 return !ftrace_location_range(addr, addr + size - 1);
408 }
409 #else
410 #define within_notrace_func(tk) (false)
411 #endif
412
413 /* Internal register function - just handle k*probes and flags */
414 static int __register_trace_kprobe(struct trace_kprobe *tk)
415 {
416 int i, ret;
417
418 if (trace_probe_is_registered(&tk->tp))
419 return -EINVAL;
420
421 if (within_notrace_func(tk)) {
422 pr_warn("Could not probe notrace function %s\n",
423 trace_kprobe_symbol(tk));
424 return -EINVAL;
425 }
426
427 for (i = 0; i < tk->tp.nr_args; i++) {
428 ret = traceprobe_update_arg(&tk->tp.args[i]);
429 if (ret)
430 return ret;
431 }
432
433 /* Set/clear disabled flag according to tp->flag */
434 if (trace_probe_is_enabled(&tk->tp))
435 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
436 else
437 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
438
439 if (trace_kprobe_is_return(tk))
440 ret = register_kretprobe(&tk->rp);
441 else
442 ret = register_kprobe(&tk->rp.kp);
443
444 if (ret == 0)
445 tk->tp.flags |= TP_FLAG_REGISTERED;
446 return ret;
447 }
448
449 /* Internal unregister function - just handle k*probes and flags */
450 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
451 {
452 if (trace_probe_is_registered(&tk->tp)) {
453 if (trace_kprobe_is_return(tk))
454 unregister_kretprobe(&tk->rp);
455 else
456 unregister_kprobe(&tk->rp.kp);
457 tk->tp.flags &= ~TP_FLAG_REGISTERED;
458 /* Cleanup kprobe for reuse */
459 if (tk->rp.kp.symbol_name)
460 tk->rp.kp.addr = NULL;
461 }
462 }
463
464 /* Unregister a trace_probe and probe_event */
465 static int unregister_trace_kprobe(struct trace_kprobe *tk)
466 {
467 /* Enabled event can not be unregistered */
468 if (trace_probe_is_enabled(&tk->tp))
469 return -EBUSY;
470
471 /* Will fail if probe is being used by ftrace or perf */
472 if (unregister_kprobe_event(tk))
473 return -EBUSY;
474
475 __unregister_trace_kprobe(tk);
476 dyn_event_remove(&tk->devent);
477
478 return 0;
479 }
480
481 /* Register a trace_probe and probe_event */
482 static int register_trace_kprobe(struct trace_kprobe *tk)
483 {
484 struct trace_kprobe *old_tk;
485 int ret;
486
487 mutex_lock(&event_mutex);
488
489 /* Delete old (same name) event if exist */
490 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
491 tk->tp.call.class->system);
492 if (old_tk) {
493 ret = unregister_trace_kprobe(old_tk);
494 if (ret < 0)
495 goto end;
496 free_trace_kprobe(old_tk);
497 }
498
499 /* Register new event */
500 ret = register_kprobe_event(tk);
501 if (ret) {
502 pr_warn("Failed to register probe event(%d)\n", ret);
503 goto end;
504 }
505
506 /* Register k*probe */
507 ret = __register_trace_kprobe(tk);
508 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
509 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
510 ret = 0;
511 }
512
513 if (ret < 0)
514 unregister_kprobe_event(tk);
515 else
516 dyn_event_add(&tk->devent);
517
518 end:
519 mutex_unlock(&event_mutex);
520 return ret;
521 }
522
523 /* Module notifier call back, checking event on the module */
524 static int trace_kprobe_module_callback(struct notifier_block *nb,
525 unsigned long val, void *data)
526 {
527 struct module *mod = data;
528 struct dyn_event *pos;
529 struct trace_kprobe *tk;
530 int ret;
531
532 if (val != MODULE_STATE_COMING)
533 return NOTIFY_DONE;
534
535 /* Update probes on coming module */
536 mutex_lock(&event_mutex);
537 for_each_trace_kprobe(tk, pos) {
538 if (trace_kprobe_within_module(tk, mod)) {
539 /* Don't need to check busy - this should have gone. */
540 __unregister_trace_kprobe(tk);
541 ret = __register_trace_kprobe(tk);
542 if (ret)
543 pr_warn("Failed to re-register probe %s on %s: %d\n",
544 trace_event_name(&tk->tp.call),
545 mod->name, ret);
546 }
547 }
548 mutex_unlock(&event_mutex);
549
550 return NOTIFY_DONE;
551 }
552
553 static struct notifier_block trace_kprobe_module_nb = {
554 .notifier_call = trace_kprobe_module_callback,
555 .priority = 1 /* Invoked after kprobe module callback */
556 };
557
558 /* Convert certain expected symbols into '_' when generating event names */
559 static inline void sanitize_event_name(char *name)
560 {
561 while (*name++ != '\0')
562 if (*name == ':' || *name == '.')
563 *name = '_';
564 }
565
566 static int trace_kprobe_create(int argc, const char *argv[])
567 {
568 /*
569 * Argument syntax:
570 * - Add kprobe:
571 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
572 * - Add kretprobe:
573 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
574 * Fetch args:
575 * $retval : fetch return value
576 * $stack : fetch stack address
577 * $stackN : fetch Nth of stack (N:0-)
578 * $comm : fetch current task comm
579 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
580 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
581 * %REG : fetch register REG
582 * Dereferencing memory fetch:
583 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
584 * Alias name of args:
585 * NAME=FETCHARG : set NAME as alias of FETCHARG.
586 * Type of args:
587 * FETCHARG:TYPE : use TYPE instead of unsigned long.
588 */
589 struct trace_kprobe *tk = NULL;
590 int i, len, ret = 0;
591 bool is_return = false;
592 char *symbol = NULL, *tmp = NULL;
593 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
594 int maxactive = 0;
595 long offset = 0;
596 void *addr = NULL;
597 char buf[MAX_EVENT_NAME_LEN];
598 unsigned int flags = TPARG_FL_KERNEL;
599
600 switch (argv[0][0]) {
601 case 'r':
602 is_return = true;
603 flags |= TPARG_FL_RETURN;
604 break;
605 case 'p':
606 break;
607 default:
608 return -ECANCELED;
609 }
610 if (argc < 2)
611 return -ECANCELED;
612
613 trace_probe_log_init("trace_kprobe", argc, argv);
614
615 event = strchr(&argv[0][1], ':');
616 if (event)
617 event++;
618
619 if (isdigit(argv[0][1])) {
620 if (!is_return) {
621 trace_probe_log_err(1, MAXACT_NO_KPROBE);
622 goto parse_error;
623 }
624 if (event)
625 len = event - &argv[0][1] - 1;
626 else
627 len = strlen(&argv[0][1]);
628 if (len > MAX_EVENT_NAME_LEN - 1) {
629 trace_probe_log_err(1, BAD_MAXACT);
630 goto parse_error;
631 }
632 memcpy(buf, &argv[0][1], len);
633 buf[len] = '\0';
634 ret = kstrtouint(buf, 0, &maxactive);
635 if (ret || !maxactive) {
636 trace_probe_log_err(1, BAD_MAXACT);
637 goto parse_error;
638 }
639 /* kretprobes instances are iterated over via a list. The
640 * maximum should stay reasonable.
641 */
642 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
643 trace_probe_log_err(1, MAXACT_TOO_BIG);
644 goto parse_error;
645 }
646 }
647
648 /* try to parse an address. if that fails, try to read the
649 * input as a symbol. */
650 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
651 trace_probe_log_set_index(1);
652 /* Check whether uprobe event specified */
653 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
654 ret = -ECANCELED;
655 goto error;
656 }
657 /* a symbol specified */
658 symbol = kstrdup(argv[1], GFP_KERNEL);
659 if (!symbol)
660 return -ENOMEM;
661 /* TODO: support .init module functions */
662 ret = traceprobe_split_symbol_offset(symbol, &offset);
663 if (ret || offset < 0 || offset > UINT_MAX) {
664 trace_probe_log_err(0, BAD_PROBE_ADDR);
665 goto parse_error;
666 }
667 if (kprobe_on_func_entry(NULL, symbol, offset))
668 flags |= TPARG_FL_FENTRY;
669 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
670 trace_probe_log_err(0, BAD_RETPROBE);
671 goto parse_error;
672 }
673 }
674
675 trace_probe_log_set_index(0);
676 if (event) {
677 ret = traceprobe_parse_event_name(&event, &group, buf,
678 event - argv[0]);
679 if (ret)
680 goto parse_error;
681 } else {
682 /* Make a new event name */
683 if (symbol)
684 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
685 is_return ? 'r' : 'p', symbol, offset);
686 else
687 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
688 is_return ? 'r' : 'p', addr);
689 sanitize_event_name(buf);
690 event = buf;
691 }
692
693 /* setup a probe */
694 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
695 argc - 2, is_return);
696 if (IS_ERR(tk)) {
697 ret = PTR_ERR(tk);
698 /* This must return -ENOMEM, else there is a bug */
699 WARN_ON_ONCE(ret != -ENOMEM);
700 goto out; /* We know tk is not allocated */
701 }
702 argc -= 2; argv += 2;
703
704 /* parse arguments */
705 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
706 tmp = kstrdup(argv[i], GFP_KERNEL);
707 if (!tmp) {
708 ret = -ENOMEM;
709 goto error;
710 }
711
712 trace_probe_log_set_index(i + 2);
713 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
714 kfree(tmp);
715 if (ret)
716 goto error; /* This can be -ENOMEM */
717 }
718
719 ret = register_trace_kprobe(tk);
720 if (ret) {
721 trace_probe_log_set_index(1);
722 if (ret == -EILSEQ)
723 trace_probe_log_err(0, BAD_INSN_BNDRY);
724 else if (ret == -ENOENT)
725 trace_probe_log_err(0, BAD_PROBE_ADDR);
726 else if (ret != -ENOMEM)
727 trace_probe_log_err(0, FAIL_REG_PROBE);
728 goto error;
729 }
730
731 out:
732 trace_probe_log_clear();
733 kfree(symbol);
734 return ret;
735
736 parse_error:
737 ret = -EINVAL;
738 error:
739 free_trace_kprobe(tk);
740 goto out;
741 }
742
743 static int create_or_delete_trace_kprobe(int argc, char **argv)
744 {
745 int ret;
746
747 if (argv[0][0] == '-')
748 return dyn_event_release(argc, argv, &trace_kprobe_ops);
749
750 ret = trace_kprobe_create(argc, (const char **)argv);
751 return ret == -ECANCELED ? -EINVAL : ret;
752 }
753
754 static int trace_kprobe_release(struct dyn_event *ev)
755 {
756 struct trace_kprobe *tk = to_trace_kprobe(ev);
757 int ret = unregister_trace_kprobe(tk);
758
759 if (!ret)
760 free_trace_kprobe(tk);
761 return ret;
762 }
763
764 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
765 {
766 struct trace_kprobe *tk = to_trace_kprobe(ev);
767 int i;
768
769 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
770 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
771 trace_event_name(&tk->tp.call));
772
773 if (!tk->symbol)
774 seq_printf(m, " 0x%p", tk->rp.kp.addr);
775 else if (tk->rp.kp.offset)
776 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
777 tk->rp.kp.offset);
778 else
779 seq_printf(m, " %s", trace_kprobe_symbol(tk));
780
781 for (i = 0; i < tk->tp.nr_args; i++)
782 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
783 seq_putc(m, '\n');
784
785 return 0;
786 }
787
788 static int probes_seq_show(struct seq_file *m, void *v)
789 {
790 struct dyn_event *ev = v;
791
792 if (!is_trace_kprobe(ev))
793 return 0;
794
795 return trace_kprobe_show(m, ev);
796 }
797
798 static const struct seq_operations probes_seq_op = {
799 .start = dyn_event_seq_start,
800 .next = dyn_event_seq_next,
801 .stop = dyn_event_seq_stop,
802 .show = probes_seq_show
803 };
804
805 static int probes_open(struct inode *inode, struct file *file)
806 {
807 int ret;
808
809 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
810 ret = dyn_events_release_all(&trace_kprobe_ops);
811 if (ret < 0)
812 return ret;
813 }
814
815 return seq_open(file, &probes_seq_op);
816 }
817
818 static ssize_t probes_write(struct file *file, const char __user *buffer,
819 size_t count, loff_t *ppos)
820 {
821 return trace_parse_run_command(file, buffer, count, ppos,
822 create_or_delete_trace_kprobe);
823 }
824
825 static const struct file_operations kprobe_events_ops = {
826 .owner = THIS_MODULE,
827 .open = probes_open,
828 .read = seq_read,
829 .llseek = seq_lseek,
830 .release = seq_release,
831 .write = probes_write,
832 };
833
834 /* Probes profiling interfaces */
835 static int probes_profile_seq_show(struct seq_file *m, void *v)
836 {
837 struct dyn_event *ev = v;
838 struct trace_kprobe *tk;
839
840 if (!is_trace_kprobe(ev))
841 return 0;
842
843 tk = to_trace_kprobe(ev);
844 seq_printf(m, " %-44s %15lu %15lu\n",
845 trace_event_name(&tk->tp.call),
846 trace_kprobe_nhit(tk),
847 tk->rp.kp.nmissed);
848
849 return 0;
850 }
851
852 static const struct seq_operations profile_seq_op = {
853 .start = dyn_event_seq_start,
854 .next = dyn_event_seq_next,
855 .stop = dyn_event_seq_stop,
856 .show = probes_profile_seq_show
857 };
858
859 static int profile_open(struct inode *inode, struct file *file)
860 {
861 return seq_open(file, &profile_seq_op);
862 }
863
864 static const struct file_operations kprobe_profile_ops = {
865 .owner = THIS_MODULE,
866 .open = profile_open,
867 .read = seq_read,
868 .llseek = seq_lseek,
869 .release = seq_release,
870 };
871
872 /* Kprobe specific fetch functions */
873
874 /* Return the length of string -- including null terminal byte */
875 static nokprobe_inline int
876 fetch_store_strlen(unsigned long addr)
877 {
878 int ret, len = 0;
879 u8 c;
880
881 do {
882 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
883 len++;
884 } while (c && ret == 0 && len < MAX_STRING_SIZE);
885
886 return (ret < 0) ? ret : len;
887 }
888
889 /*
890 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
891 * length and relative data location.
892 */
893 static nokprobe_inline int
894 fetch_store_string(unsigned long addr, void *dest, void *base)
895 {
896 int maxlen = get_loc_len(*(u32 *)dest);
897 u8 *dst = get_loc_data(dest, base);
898 long ret;
899
900 if (unlikely(!maxlen))
901 return -ENOMEM;
902 /*
903 * Try to get string again, since the string can be changed while
904 * probing.
905 */
906 ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
907
908 if (ret >= 0)
909 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
910 return ret;
911 }
912
913 static nokprobe_inline int
914 probe_mem_read(void *dest, void *src, size_t size)
915 {
916 return probe_kernel_read(dest, src, size);
917 }
918
919 /* Note that we don't verify it, since the code does not come from user space */
920 static int
921 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
922 void *base)
923 {
924 unsigned long val;
925
926 retry:
927 /* 1st stage: get value from context */
928 switch (code->op) {
929 case FETCH_OP_REG:
930 val = regs_get_register(regs, code->param);
931 break;
932 case FETCH_OP_STACK:
933 val = regs_get_kernel_stack_nth(regs, code->param);
934 break;
935 case FETCH_OP_STACKP:
936 val = kernel_stack_pointer(regs);
937 break;
938 case FETCH_OP_RETVAL:
939 val = regs_return_value(regs);
940 break;
941 case FETCH_OP_IMM:
942 val = code->immediate;
943 break;
944 case FETCH_OP_COMM:
945 val = (unsigned long)current->comm;
946 break;
947 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
948 case FETCH_OP_ARG:
949 val = regs_get_kernel_argument(regs, code->param);
950 break;
951 #endif
952 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
953 code++;
954 goto retry;
955 default:
956 return -EILSEQ;
957 }
958 code++;
959
960 return process_fetch_insn_bottom(code, val, dest, base);
961 }
962 NOKPROBE_SYMBOL(process_fetch_insn)
963
964 /* Kprobe handler */
965 static nokprobe_inline void
966 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
967 struct trace_event_file *trace_file)
968 {
969 struct kprobe_trace_entry_head *entry;
970 struct ring_buffer_event *event;
971 struct ring_buffer *buffer;
972 int size, dsize, pc;
973 unsigned long irq_flags;
974 struct trace_event_call *call = &tk->tp.call;
975
976 WARN_ON(call != trace_file->event_call);
977
978 if (trace_trigger_soft_disabled(trace_file))
979 return;
980
981 local_save_flags(irq_flags);
982 pc = preempt_count();
983
984 dsize = __get_data_size(&tk->tp, regs);
985 size = sizeof(*entry) + tk->tp.size + dsize;
986
987 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
988 call->event.type,
989 size, irq_flags, pc);
990 if (!event)
991 return;
992
993 entry = ring_buffer_event_data(event);
994 entry->ip = (unsigned long)tk->rp.kp.addr;
995 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
996
997 event_trigger_unlock_commit_regs(trace_file, buffer, event,
998 entry, irq_flags, pc, regs);
999 }
1000
1001 static void
1002 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1003 {
1004 struct event_file_link *link;
1005
1006 list_for_each_entry_rcu(link, &tk->tp.files, list)
1007 __kprobe_trace_func(tk, regs, link->file);
1008 }
1009 NOKPROBE_SYMBOL(kprobe_trace_func);
1010
1011 /* Kretprobe handler */
1012 static nokprobe_inline void
1013 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1014 struct pt_regs *regs,
1015 struct trace_event_file *trace_file)
1016 {
1017 struct kretprobe_trace_entry_head *entry;
1018 struct ring_buffer_event *event;
1019 struct ring_buffer *buffer;
1020 int size, pc, dsize;
1021 unsigned long irq_flags;
1022 struct trace_event_call *call = &tk->tp.call;
1023
1024 WARN_ON(call != trace_file->event_call);
1025
1026 if (trace_trigger_soft_disabled(trace_file))
1027 return;
1028
1029 local_save_flags(irq_flags);
1030 pc = preempt_count();
1031
1032 dsize = __get_data_size(&tk->tp, regs);
1033 size = sizeof(*entry) + tk->tp.size + dsize;
1034
1035 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1036 call->event.type,
1037 size, irq_flags, pc);
1038 if (!event)
1039 return;
1040
1041 entry = ring_buffer_event_data(event);
1042 entry->func = (unsigned long)tk->rp.kp.addr;
1043 entry->ret_ip = (unsigned long)ri->ret_addr;
1044 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1045
1046 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1047 entry, irq_flags, pc, regs);
1048 }
1049
1050 static void
1051 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1052 struct pt_regs *regs)
1053 {
1054 struct event_file_link *link;
1055
1056 list_for_each_entry_rcu(link, &tk->tp.files, list)
1057 __kretprobe_trace_func(tk, ri, regs, link->file);
1058 }
1059 NOKPROBE_SYMBOL(kretprobe_trace_func);
1060
1061 /* Event entry printers */
1062 static enum print_line_t
1063 print_kprobe_event(struct trace_iterator *iter, int flags,
1064 struct trace_event *event)
1065 {
1066 struct kprobe_trace_entry_head *field;
1067 struct trace_seq *s = &iter->seq;
1068 struct trace_probe *tp;
1069
1070 field = (struct kprobe_trace_entry_head *)iter->ent;
1071 tp = container_of(event, struct trace_probe, call.event);
1072
1073 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1074
1075 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1076 goto out;
1077
1078 trace_seq_putc(s, ')');
1079
1080 if (print_probe_args(s, tp->args, tp->nr_args,
1081 (u8 *)&field[1], field) < 0)
1082 goto out;
1083
1084 trace_seq_putc(s, '\n');
1085 out:
1086 return trace_handle_return(s);
1087 }
1088
1089 static enum print_line_t
1090 print_kretprobe_event(struct trace_iterator *iter, int flags,
1091 struct trace_event *event)
1092 {
1093 struct kretprobe_trace_entry_head *field;
1094 struct trace_seq *s = &iter->seq;
1095 struct trace_probe *tp;
1096
1097 field = (struct kretprobe_trace_entry_head *)iter->ent;
1098 tp = container_of(event, struct trace_probe, call.event);
1099
1100 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1101
1102 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1103 goto out;
1104
1105 trace_seq_puts(s, " <- ");
1106
1107 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1108 goto out;
1109
1110 trace_seq_putc(s, ')');
1111
1112 if (print_probe_args(s, tp->args, tp->nr_args,
1113 (u8 *)&field[1], field) < 0)
1114 goto out;
1115
1116 trace_seq_putc(s, '\n');
1117
1118 out:
1119 return trace_handle_return(s);
1120 }
1121
1122
1123 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1124 {
1125 int ret;
1126 struct kprobe_trace_entry_head field;
1127 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1128
1129 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1130
1131 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1132 }
1133
1134 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1135 {
1136 int ret;
1137 struct kretprobe_trace_entry_head field;
1138 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1139
1140 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1141 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1142
1143 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1144 }
1145
1146 #ifdef CONFIG_PERF_EVENTS
1147
1148 /* Kprobe profile handler */
1149 static int
1150 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1151 {
1152 struct trace_event_call *call = &tk->tp.call;
1153 struct kprobe_trace_entry_head *entry;
1154 struct hlist_head *head;
1155 int size, __size, dsize;
1156 int rctx;
1157
1158 if (bpf_prog_array_valid(call)) {
1159 unsigned long orig_ip = instruction_pointer(regs);
1160 int ret;
1161
1162 ret = trace_call_bpf(call, regs);
1163
1164 /*
1165 * We need to check and see if we modified the pc of the
1166 * pt_regs, and if so return 1 so that we don't do the
1167 * single stepping.
1168 */
1169 if (orig_ip != instruction_pointer(regs))
1170 return 1;
1171 if (!ret)
1172 return 0;
1173 }
1174
1175 head = this_cpu_ptr(call->perf_events);
1176 if (hlist_empty(head))
1177 return 0;
1178
1179 dsize = __get_data_size(&tk->tp, regs);
1180 __size = sizeof(*entry) + tk->tp.size + dsize;
1181 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1182 size -= sizeof(u32);
1183
1184 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1185 if (!entry)
1186 return 0;
1187
1188 entry->ip = (unsigned long)tk->rp.kp.addr;
1189 memset(&entry[1], 0, dsize);
1190 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1191 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1192 head, NULL);
1193 return 0;
1194 }
1195 NOKPROBE_SYMBOL(kprobe_perf_func);
1196
1197 /* Kretprobe profile handler */
1198 static void
1199 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1200 struct pt_regs *regs)
1201 {
1202 struct trace_event_call *call = &tk->tp.call;
1203 struct kretprobe_trace_entry_head *entry;
1204 struct hlist_head *head;
1205 int size, __size, dsize;
1206 int rctx;
1207
1208 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1209 return;
1210
1211 head = this_cpu_ptr(call->perf_events);
1212 if (hlist_empty(head))
1213 return;
1214
1215 dsize = __get_data_size(&tk->tp, regs);
1216 __size = sizeof(*entry) + tk->tp.size + dsize;
1217 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1218 size -= sizeof(u32);
1219
1220 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1221 if (!entry)
1222 return;
1223
1224 entry->func = (unsigned long)tk->rp.kp.addr;
1225 entry->ret_ip = (unsigned long)ri->ret_addr;
1226 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1227 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1228 head, NULL);
1229 }
1230 NOKPROBE_SYMBOL(kretprobe_perf_func);
1231
1232 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1233 const char **symbol, u64 *probe_offset,
1234 u64 *probe_addr, bool perf_type_tracepoint)
1235 {
1236 const char *pevent = trace_event_name(event->tp_event);
1237 const char *group = event->tp_event->class->system;
1238 struct trace_kprobe *tk;
1239
1240 if (perf_type_tracepoint)
1241 tk = find_trace_kprobe(pevent, group);
1242 else
1243 tk = event->tp_event->data;
1244 if (!tk)
1245 return -EINVAL;
1246
1247 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1248 : BPF_FD_TYPE_KPROBE;
1249 if (tk->symbol) {
1250 *symbol = tk->symbol;
1251 *probe_offset = tk->rp.kp.offset;
1252 *probe_addr = 0;
1253 } else {
1254 *symbol = NULL;
1255 *probe_offset = 0;
1256 *probe_addr = (unsigned long)tk->rp.kp.addr;
1257 }
1258 return 0;
1259 }
1260 #endif /* CONFIG_PERF_EVENTS */
1261
1262 /*
1263 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1264 *
1265 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1266 * lockless, but we can't race with this __init function.
1267 */
1268 static int kprobe_register(struct trace_event_call *event,
1269 enum trace_reg type, void *data)
1270 {
1271 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1272 struct trace_event_file *file = data;
1273
1274 switch (type) {
1275 case TRACE_REG_REGISTER:
1276 return enable_trace_kprobe(tk, file);
1277 case TRACE_REG_UNREGISTER:
1278 return disable_trace_kprobe(tk, file);
1279
1280 #ifdef CONFIG_PERF_EVENTS
1281 case TRACE_REG_PERF_REGISTER:
1282 return enable_trace_kprobe(tk, NULL);
1283 case TRACE_REG_PERF_UNREGISTER:
1284 return disable_trace_kprobe(tk, NULL);
1285 case TRACE_REG_PERF_OPEN:
1286 case TRACE_REG_PERF_CLOSE:
1287 case TRACE_REG_PERF_ADD:
1288 case TRACE_REG_PERF_DEL:
1289 return 0;
1290 #endif
1291 }
1292 return 0;
1293 }
1294
1295 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1296 {
1297 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1298 int ret = 0;
1299
1300 raw_cpu_inc(*tk->nhit);
1301
1302 if (tk->tp.flags & TP_FLAG_TRACE)
1303 kprobe_trace_func(tk, regs);
1304 #ifdef CONFIG_PERF_EVENTS
1305 if (tk->tp.flags & TP_FLAG_PROFILE)
1306 ret = kprobe_perf_func(tk, regs);
1307 #endif
1308 return ret;
1309 }
1310 NOKPROBE_SYMBOL(kprobe_dispatcher);
1311
1312 static int
1313 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1314 {
1315 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1316
1317 raw_cpu_inc(*tk->nhit);
1318
1319 if (tk->tp.flags & TP_FLAG_TRACE)
1320 kretprobe_trace_func(tk, ri, regs);
1321 #ifdef CONFIG_PERF_EVENTS
1322 if (tk->tp.flags & TP_FLAG_PROFILE)
1323 kretprobe_perf_func(tk, ri, regs);
1324 #endif
1325 return 0; /* We don't tweek kernel, so just return 0 */
1326 }
1327 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1328
1329 static struct trace_event_functions kretprobe_funcs = {
1330 .trace = print_kretprobe_event
1331 };
1332
1333 static struct trace_event_functions kprobe_funcs = {
1334 .trace = print_kprobe_event
1335 };
1336
1337 static inline void init_trace_event_call(struct trace_kprobe *tk,
1338 struct trace_event_call *call)
1339 {
1340 INIT_LIST_HEAD(&call->class->fields);
1341 if (trace_kprobe_is_return(tk)) {
1342 call->event.funcs = &kretprobe_funcs;
1343 call->class->define_fields = kretprobe_event_define_fields;
1344 } else {
1345 call->event.funcs = &kprobe_funcs;
1346 call->class->define_fields = kprobe_event_define_fields;
1347 }
1348
1349 call->flags = TRACE_EVENT_FL_KPROBE;
1350 call->class->reg = kprobe_register;
1351 call->data = tk;
1352 }
1353
1354 static int register_kprobe_event(struct trace_kprobe *tk)
1355 {
1356 struct trace_event_call *call = &tk->tp.call;
1357 int ret = 0;
1358
1359 init_trace_event_call(tk, call);
1360
1361 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1362 return -ENOMEM;
1363 ret = register_trace_event(&call->event);
1364 if (!ret) {
1365 kfree(call->print_fmt);
1366 return -ENODEV;
1367 }
1368 ret = trace_add_event_call(call);
1369 if (ret) {
1370 pr_info("Failed to register kprobe event: %s\n",
1371 trace_event_name(call));
1372 kfree(call->print_fmt);
1373 unregister_trace_event(&call->event);
1374 }
1375 return ret;
1376 }
1377
1378 static int unregister_kprobe_event(struct trace_kprobe *tk)
1379 {
1380 int ret;
1381
1382 /* tp->event is unregistered in trace_remove_event_call() */
1383 ret = trace_remove_event_call(&tk->tp.call);
1384 if (!ret)
1385 kfree(tk->tp.call.print_fmt);
1386 return ret;
1387 }
1388
1389 #ifdef CONFIG_PERF_EVENTS
1390 /* create a trace_kprobe, but don't add it to global lists */
1391 struct trace_event_call *
1392 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1393 bool is_return)
1394 {
1395 struct trace_kprobe *tk;
1396 int ret;
1397 char *event;
1398
1399 /*
1400 * local trace_kprobes are not added to dyn_event, so they are never
1401 * searched in find_trace_kprobe(). Therefore, there is no concern of
1402 * duplicated name here.
1403 */
1404 event = func ? func : "DUMMY_EVENT";
1405
1406 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1407 offs, 0 /* maxactive */, 0 /* nargs */,
1408 is_return);
1409
1410 if (IS_ERR(tk)) {
1411 pr_info("Failed to allocate trace_probe.(%d)\n",
1412 (int)PTR_ERR(tk));
1413 return ERR_CAST(tk);
1414 }
1415
1416 init_trace_event_call(tk, &tk->tp.call);
1417
1418 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1419 ret = -ENOMEM;
1420 goto error;
1421 }
1422
1423 ret = __register_trace_kprobe(tk);
1424 if (ret < 0) {
1425 kfree(tk->tp.call.print_fmt);
1426 goto error;
1427 }
1428
1429 return &tk->tp.call;
1430 error:
1431 free_trace_kprobe(tk);
1432 return ERR_PTR(ret);
1433 }
1434
1435 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1436 {
1437 struct trace_kprobe *tk;
1438
1439 tk = container_of(event_call, struct trace_kprobe, tp.call);
1440
1441 if (trace_probe_is_enabled(&tk->tp)) {
1442 WARN_ON(1);
1443 return;
1444 }
1445
1446 __unregister_trace_kprobe(tk);
1447
1448 kfree(tk->tp.call.print_fmt);
1449 free_trace_kprobe(tk);
1450 }
1451 #endif /* CONFIG_PERF_EVENTS */
1452
1453 /* Make a tracefs interface for controlling probe points */
1454 static __init int init_kprobe_trace(void)
1455 {
1456 struct dentry *d_tracer;
1457 struct dentry *entry;
1458 int ret;
1459
1460 ret = dyn_event_register(&trace_kprobe_ops);
1461 if (ret)
1462 return ret;
1463
1464 if (register_module_notifier(&trace_kprobe_module_nb))
1465 return -EINVAL;
1466
1467 d_tracer = tracing_init_dentry();
1468 if (IS_ERR(d_tracer))
1469 return 0;
1470
1471 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1472 NULL, &kprobe_events_ops);
1473
1474 /* Event list interface */
1475 if (!entry)
1476 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1477
1478 /* Profile interface */
1479 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1480 NULL, &kprobe_profile_ops);
1481
1482 if (!entry)
1483 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1484 return 0;
1485 }
1486 fs_initcall(init_kprobe_trace);
1487
1488
1489 #ifdef CONFIG_FTRACE_STARTUP_TEST
1490 static __init struct trace_event_file *
1491 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1492 {
1493 struct trace_event_file *file;
1494
1495 list_for_each_entry(file, &tr->events, list)
1496 if (file->event_call == &tk->tp.call)
1497 return file;
1498
1499 return NULL;
1500 }
1501
1502 /*
1503 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1504 * stage, we can do this lockless.
1505 */
1506 static __init int kprobe_trace_self_tests_init(void)
1507 {
1508 int ret, warn = 0;
1509 int (*target)(int, int, int, int, int, int);
1510 struct trace_kprobe *tk;
1511 struct trace_event_file *file;
1512
1513 if (tracing_is_disabled())
1514 return -ENODEV;
1515
1516 target = kprobe_trace_selftest_target;
1517
1518 pr_info("Testing kprobe tracing: ");
1519
1520 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1521 create_or_delete_trace_kprobe);
1522 if (WARN_ON_ONCE(ret)) {
1523 pr_warn("error on probing function entry.\n");
1524 warn++;
1525 } else {
1526 /* Enable trace point */
1527 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1528 if (WARN_ON_ONCE(tk == NULL)) {
1529 pr_warn("error on getting new probe.\n");
1530 warn++;
1531 } else {
1532 file = find_trace_probe_file(tk, top_trace_array());
1533 if (WARN_ON_ONCE(file == NULL)) {
1534 pr_warn("error on getting probe file.\n");
1535 warn++;
1536 } else
1537 enable_trace_kprobe(tk, file);
1538 }
1539 }
1540
1541 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1542 create_or_delete_trace_kprobe);
1543 if (WARN_ON_ONCE(ret)) {
1544 pr_warn("error on probing function return.\n");
1545 warn++;
1546 } else {
1547 /* Enable trace point */
1548 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1549 if (WARN_ON_ONCE(tk == NULL)) {
1550 pr_warn("error on getting 2nd new probe.\n");
1551 warn++;
1552 } else {
1553 file = find_trace_probe_file(tk, top_trace_array());
1554 if (WARN_ON_ONCE(file == NULL)) {
1555 pr_warn("error on getting probe file.\n");
1556 warn++;
1557 } else
1558 enable_trace_kprobe(tk, file);
1559 }
1560 }
1561
1562 if (warn)
1563 goto end;
1564
1565 ret = target(1, 2, 3, 4, 5, 6);
1566
1567 /*
1568 * Not expecting an error here, the check is only to prevent the
1569 * optimizer from removing the call to target() as otherwise there
1570 * are no side-effects and the call is never performed.
1571 */
1572 if (ret != 21)
1573 warn++;
1574
1575 /* Disable trace points before removing it */
1576 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1577 if (WARN_ON_ONCE(tk == NULL)) {
1578 pr_warn("error on getting test probe.\n");
1579 warn++;
1580 } else {
1581 if (trace_kprobe_nhit(tk) != 1) {
1582 pr_warn("incorrect number of testprobe hits\n");
1583 warn++;
1584 }
1585
1586 file = find_trace_probe_file(tk, top_trace_array());
1587 if (WARN_ON_ONCE(file == NULL)) {
1588 pr_warn("error on getting probe file.\n");
1589 warn++;
1590 } else
1591 disable_trace_kprobe(tk, file);
1592 }
1593
1594 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1595 if (WARN_ON_ONCE(tk == NULL)) {
1596 pr_warn("error on getting 2nd test probe.\n");
1597 warn++;
1598 } else {
1599 if (trace_kprobe_nhit(tk) != 1) {
1600 pr_warn("incorrect number of testprobe2 hits\n");
1601 warn++;
1602 }
1603
1604 file = find_trace_probe_file(tk, top_trace_array());
1605 if (WARN_ON_ONCE(file == NULL)) {
1606 pr_warn("error on getting probe file.\n");
1607 warn++;
1608 } else
1609 disable_trace_kprobe(tk, file);
1610 }
1611
1612 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1613 if (WARN_ON_ONCE(ret)) {
1614 pr_warn("error on deleting a probe.\n");
1615 warn++;
1616 }
1617
1618 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1619 if (WARN_ON_ONCE(ret)) {
1620 pr_warn("error on deleting a probe.\n");
1621 warn++;
1622 }
1623
1624 end:
1625 ret = dyn_events_release_all(&trace_kprobe_ops);
1626 if (WARN_ON_ONCE(ret)) {
1627 pr_warn("error on cleaning up probes.\n");
1628 warn++;
1629 }
1630 /*
1631 * Wait for the optimizer work to finish. Otherwise it might fiddle
1632 * with probes in already freed __init text.
1633 */
1634 wait_for_kprobe_optimizer();
1635 if (warn)
1636 pr_cont("NG: Some tests are failed. Please check them.\n");
1637 else
1638 pr_cont("OK\n");
1639 return 0;
1640 }
1641
1642 late_initcall(kprobe_trace_self_tests_init);
1643
1644 #endif
Linux with added FPC-III support