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1/*
2 * Kprobes-based tracing events
3 *
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/module.h>
21#include <linux/uaccess.h>
22
23#include "trace_probe.h"
24
25#define KPROBE_EVENT_SYSTEM "kprobes"
26
27/**
28 * Kprobe event core functions
29 */
30struct trace_kprobe {
31 struct list_head list;
32 struct kretprobe rp; /* Use rp.kp for kprobe use */
33 unsigned long __percpu *nhit;
34 const char *symbol; /* symbol name */
35 struct trace_probe tp;
36};
37
38#define SIZEOF_TRACE_KPROBE(n) \
39 (offsetof(struct trace_kprobe, tp.args) + \
40 (sizeof(struct probe_arg) * (n)))
41
42
43static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
44{
45 return tk->rp.handler != NULL;
46}
47
48static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
49{
50 return tk->symbol ? tk->symbol : "unknown";
51}
52
53static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
54{
55 return tk->rp.kp.offset;
56}
57
58static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
59{
60 return !!(kprobe_gone(&tk->rp.kp));
61}
62
63static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
64 struct module *mod)
65{
66 int len = strlen(mod->name);
67 const char *name = trace_kprobe_symbol(tk);
68 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
69}
70
71static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
72{
73 return !!strchr(trace_kprobe_symbol(tk), ':');
74}
75
76static int register_kprobe_event(struct trace_kprobe *tk);
77static int unregister_kprobe_event(struct trace_kprobe *tk);
78
79static DEFINE_MUTEX(probe_lock);
80static LIST_HEAD(probe_list);
81
82static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
83static int kretprobe_dispatcher(struct kretprobe_instance *ri,
84 struct pt_regs *regs);
85
86/* Memory fetching by symbol */
87struct symbol_cache {
88 char *symbol;
89 long offset;
90 unsigned long addr;
91};
92
93unsigned long update_symbol_cache(struct symbol_cache *sc)
94{
95 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
96
97 if (sc->addr)
98 sc->addr += sc->offset;
99
100 return sc->addr;
101}
102
103void free_symbol_cache(struct symbol_cache *sc)
104{
105 kfree(sc->symbol);
106 kfree(sc);
107}
108
109struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
110{
111 struct symbol_cache *sc;
112
113 if (!sym || strlen(sym) == 0)
114 return NULL;
115
116 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
117 if (!sc)
118 return NULL;
119
120 sc->symbol = kstrdup(sym, GFP_KERNEL);
121 if (!sc->symbol) {
122 kfree(sc);
123 return NULL;
124 }
125 sc->offset = offset;
126 update_symbol_cache(sc);
127
128 return sc;
129}
130
131/*
132 * Kprobes-specific fetch functions
133 */
134#define DEFINE_FETCH_stack(type) \
135static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
136 void *offset, void *dest) \
137{ \
138 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
139 (unsigned int)((unsigned long)offset)); \
140} \
141NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
142
143DEFINE_BASIC_FETCH_FUNCS(stack)
144/* No string on the stack entry */
145#define fetch_stack_string NULL
146#define fetch_stack_string_size NULL
147
148#define DEFINE_FETCH_memory(type) \
149static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
150 void *addr, void *dest) \
151{ \
152 type retval; \
153 if (probe_kernel_address(addr, retval)) \
154 *(type *)dest = 0; \
155 else \
156 *(type *)dest = retval; \
157} \
158NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
159
160DEFINE_BASIC_FETCH_FUNCS(memory)
161/*
162 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
163 * length and relative data location.
164 */
165static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
166 void *addr, void *dest)
167{
168 int maxlen = get_rloc_len(*(u32 *)dest);
169 u8 *dst = get_rloc_data(dest);
170 long ret;
171
172 if (!maxlen)
173 return;
174
175 /*
176 * Try to get string again, since the string can be changed while
177 * probing.
178 */
179 ret = strncpy_from_unsafe(dst, addr, maxlen);
180
181 if (ret < 0) { /* Failed to fetch string */
182 dst[0] = '\0';
183 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
184 } else {
185 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
186 }
187}
188NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
189
190/* Return the length of string -- including null terminal byte */
191static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
192 void *addr, void *dest)
193{
194 mm_segment_t old_fs;
195 int ret, len = 0;
196 u8 c;
197
198 old_fs = get_fs();
199 set_fs(KERNEL_DS);
200 pagefault_disable();
201
202 do {
203 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
204 len++;
205 } while (c && ret == 0 && len < MAX_STRING_SIZE);
206
207 pagefault_enable();
208 set_fs(old_fs);
209
210 if (ret < 0) /* Failed to check the length */
211 *(u32 *)dest = 0;
212 else
213 *(u32 *)dest = len;
214}
215NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
216
217#define DEFINE_FETCH_symbol(type) \
218void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
219{ \
220 struct symbol_cache *sc = data; \
221 if (sc->addr) \
222 fetch_memory_##type(regs, (void *)sc->addr, dest); \
223 else \
224 *(type *)dest = 0; \
225} \
226NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
227
228DEFINE_BASIC_FETCH_FUNCS(symbol)
229DEFINE_FETCH_symbol(string)
230DEFINE_FETCH_symbol(string_size)
231
232/* kprobes don't support file_offset fetch methods */
233#define fetch_file_offset_u8 NULL
234#define fetch_file_offset_u16 NULL
235#define fetch_file_offset_u32 NULL
236#define fetch_file_offset_u64 NULL
237#define fetch_file_offset_string NULL
238#define fetch_file_offset_string_size NULL
239
240/* Fetch type information table */
241static const struct fetch_type kprobes_fetch_type_table[] = {
242 /* Special types */
243 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
244 sizeof(u32), 1, "__data_loc char[]"),
245 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
246 string_size, sizeof(u32), 0, "u32"),
247 /* Basic types */
248 ASSIGN_FETCH_TYPE(u8, u8, 0),
249 ASSIGN_FETCH_TYPE(u16, u16, 0),
250 ASSIGN_FETCH_TYPE(u32, u32, 0),
251 ASSIGN_FETCH_TYPE(u64, u64, 0),
252 ASSIGN_FETCH_TYPE(s8, u8, 1),
253 ASSIGN_FETCH_TYPE(s16, u16, 1),
254 ASSIGN_FETCH_TYPE(s32, u32, 1),
255 ASSIGN_FETCH_TYPE(s64, u64, 1),
256
257 ASSIGN_FETCH_TYPE_END
258};
259
260/*
261 * Allocate new trace_probe and initialize it (including kprobes).
262 */
263static struct trace_kprobe *alloc_trace_kprobe(const char *group,
264 const char *event,
265 void *addr,
266 const char *symbol,
267 unsigned long offs,
268 int nargs, bool is_return)
269{
270 struct trace_kprobe *tk;
271 int ret = -ENOMEM;
272
273 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
274 if (!tk)
275 return ERR_PTR(ret);
276
277 tk->nhit = alloc_percpu(unsigned long);
278 if (!tk->nhit)
279 goto error;
280
281 if (symbol) {
282 tk->symbol = kstrdup(symbol, GFP_KERNEL);
283 if (!tk->symbol)
284 goto error;
285 tk->rp.kp.symbol_name = tk->symbol;
286 tk->rp.kp.offset = offs;
287 } else
288 tk->rp.kp.addr = addr;
289
290 if (is_return)
291 tk->rp.handler = kretprobe_dispatcher;
292 else
293 tk->rp.kp.pre_handler = kprobe_dispatcher;
294
295 if (!event || !is_good_name(event)) {
296 ret = -EINVAL;
297 goto error;
298 }
299
300 tk->tp.call.class = &tk->tp.class;
301 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
302 if (!tk->tp.call.name)
303 goto error;
304
305 if (!group || !is_good_name(group)) {
306 ret = -EINVAL;
307 goto error;
308 }
309
310 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
311 if (!tk->tp.class.system)
312 goto error;
313
314 INIT_LIST_HEAD(&tk->list);
315 INIT_LIST_HEAD(&tk->tp.files);
316 return tk;
317error:
318 kfree(tk->tp.call.name);
319 kfree(tk->symbol);
320 free_percpu(tk->nhit);
321 kfree(tk);
322 return ERR_PTR(ret);
323}
324
325static void free_trace_kprobe(struct trace_kprobe *tk)
326{
327 int i;
328
329 for (i = 0; i < tk->tp.nr_args; i++)
330 traceprobe_free_probe_arg(&tk->tp.args[i]);
331
332 kfree(tk->tp.call.class->system);
333 kfree(tk->tp.call.name);
334 kfree(tk->symbol);
335 free_percpu(tk->nhit);
336 kfree(tk);
337}
338
339static struct trace_kprobe *find_trace_kprobe(const char *event,
340 const char *group)
341{
342 struct trace_kprobe *tk;
343
344 list_for_each_entry(tk, &probe_list, list)
345 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
346 strcmp(tk->tp.call.class->system, group) == 0)
347 return tk;
348 return NULL;
349}
350
351/*
352 * Enable trace_probe
353 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
354 */
355static int
356enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
357{
358 int ret = 0;
359
360 if (file) {
361 struct event_file_link *link;
362
363 link = kmalloc(sizeof(*link), GFP_KERNEL);
364 if (!link) {
365 ret = -ENOMEM;
366 goto out;
367 }
368
369 link->file = file;
370 list_add_tail_rcu(&link->list, &tk->tp.files);
371
372 tk->tp.flags |= TP_FLAG_TRACE;
373 } else
374 tk->tp.flags |= TP_FLAG_PROFILE;
375
376 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
377 if (trace_kprobe_is_return(tk))
378 ret = enable_kretprobe(&tk->rp);
379 else
380 ret = enable_kprobe(&tk->rp.kp);
381 }
382 out:
383 return ret;
384}
385
386/*
387 * Disable trace_probe
388 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
389 */
390static int
391disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
392{
393 struct event_file_link *link = NULL;
394 int wait = 0;
395 int ret = 0;
396
397 if (file) {
398 link = find_event_file_link(&tk->tp, file);
399 if (!link) {
400 ret = -EINVAL;
401 goto out;
402 }
403
404 list_del_rcu(&link->list);
405 wait = 1;
406 if (!list_empty(&tk->tp.files))
407 goto out;
408
409 tk->tp.flags &= ~TP_FLAG_TRACE;
410 } else
411 tk->tp.flags &= ~TP_FLAG_PROFILE;
412
413 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
414 if (trace_kprobe_is_return(tk))
415 disable_kretprobe(&tk->rp);
416 else
417 disable_kprobe(&tk->rp.kp);
418 wait = 1;
419 }
420 out:
421 if (wait) {
422 /*
423 * Synchronize with kprobe_trace_func/kretprobe_trace_func
424 * to ensure disabled (all running handlers are finished).
425 * This is not only for kfree(), but also the caller,
426 * trace_remove_event_call() supposes it for releasing
427 * event_call related objects, which will be accessed in
428 * the kprobe_trace_func/kretprobe_trace_func.
429 */
430 synchronize_sched();
431 kfree(link); /* Ignored if link == NULL */
432 }
433
434 return ret;
435}
436
437/* Internal register function - just handle k*probes and flags */
438static int __register_trace_kprobe(struct trace_kprobe *tk)
439{
440 int i, ret;
441
442 if (trace_probe_is_registered(&tk->tp))
443 return -EINVAL;
444
445 for (i = 0; i < tk->tp.nr_args; i++)
446 traceprobe_update_arg(&tk->tp.args[i]);
447
448 /* Set/clear disabled flag according to tp->flag */
449 if (trace_probe_is_enabled(&tk->tp))
450 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
451 else
452 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
453
454 if (trace_kprobe_is_return(tk))
455 ret = register_kretprobe(&tk->rp);
456 else
457 ret = register_kprobe(&tk->rp.kp);
458
459 if (ret == 0)
460 tk->tp.flags |= TP_FLAG_REGISTERED;
461 else {
462 pr_warn("Could not insert probe at %s+%lu: %d\n",
463 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
464 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
465 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
466 ret = 0;
467 } else if (ret == -EILSEQ) {
468 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
469 tk->rp.kp.addr);
470 ret = -EINVAL;
471 }
472 }
473
474 return ret;
475}
476
477/* Internal unregister function - just handle k*probes and flags */
478static void __unregister_trace_kprobe(struct trace_kprobe *tk)
479{
480 if (trace_probe_is_registered(&tk->tp)) {
481 if (trace_kprobe_is_return(tk))
482 unregister_kretprobe(&tk->rp);
483 else
484 unregister_kprobe(&tk->rp.kp);
485 tk->tp.flags &= ~TP_FLAG_REGISTERED;
486 /* Cleanup kprobe for reuse */
487 if (tk->rp.kp.symbol_name)
488 tk->rp.kp.addr = NULL;
489 }
490}
491
492/* Unregister a trace_probe and probe_event: call with locking probe_lock */
493static int unregister_trace_kprobe(struct trace_kprobe *tk)
494{
495 /* Enabled event can not be unregistered */
496 if (trace_probe_is_enabled(&tk->tp))
497 return -EBUSY;
498
499 /* Will fail if probe is being used by ftrace or perf */
500 if (unregister_kprobe_event(tk))
501 return -EBUSY;
502
503 __unregister_trace_kprobe(tk);
504 list_del(&tk->list);
505
506 return 0;
507}
508
509/* Register a trace_probe and probe_event */
510static int register_trace_kprobe(struct trace_kprobe *tk)
511{
512 struct trace_kprobe *old_tk;
513 int ret;
514
515 mutex_lock(&probe_lock);
516
517 /* Delete old (same name) event if exist */
518 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
519 tk->tp.call.class->system);
520 if (old_tk) {
521 ret = unregister_trace_kprobe(old_tk);
522 if (ret < 0)
523 goto end;
524 free_trace_kprobe(old_tk);
525 }
526
527 /* Register new event */
528 ret = register_kprobe_event(tk);
529 if (ret) {
530 pr_warn("Failed to register probe event(%d)\n", ret);
531 goto end;
532 }
533
534 /* Register k*probe */
535 ret = __register_trace_kprobe(tk);
536 if (ret < 0)
537 unregister_kprobe_event(tk);
538 else
539 list_add_tail(&tk->list, &probe_list);
540
541end:
542 mutex_unlock(&probe_lock);
543 return ret;
544}
545
546/* Module notifier call back, checking event on the module */
547static int trace_kprobe_module_callback(struct notifier_block *nb,
548 unsigned long val, void *data)
549{
550 struct module *mod = data;
551 struct trace_kprobe *tk;
552 int ret;
553
554 if (val != MODULE_STATE_COMING)
555 return NOTIFY_DONE;
556
557 /* Update probes on coming module */
558 mutex_lock(&probe_lock);
559 list_for_each_entry(tk, &probe_list, list) {
560 if (trace_kprobe_within_module(tk, mod)) {
561 /* Don't need to check busy - this should have gone. */
562 __unregister_trace_kprobe(tk);
563 ret = __register_trace_kprobe(tk);
564 if (ret)
565 pr_warn("Failed to re-register probe %s on %s: %d\n",
566 trace_event_name(&tk->tp.call),
567 mod->name, ret);
568 }
569 }
570 mutex_unlock(&probe_lock);
571
572 return NOTIFY_DONE;
573}
574
575static struct notifier_block trace_kprobe_module_nb = {
576 .notifier_call = trace_kprobe_module_callback,
577 .priority = 1 /* Invoked after kprobe module callback */
578};
579
580static int create_trace_kprobe(int argc, char **argv)
581{
582 /*
583 * Argument syntax:
584 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
585 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
586 * Fetch args:
587 * $retval : fetch return value
588 * $stack : fetch stack address
589 * $stackN : fetch Nth of stack (N:0-)
590 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
591 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
592 * %REG : fetch register REG
593 * Dereferencing memory fetch:
594 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
595 * Alias name of args:
596 * NAME=FETCHARG : set NAME as alias of FETCHARG.
597 * Type of args:
598 * FETCHARG:TYPE : use TYPE instead of unsigned long.
599 */
600 struct trace_kprobe *tk;
601 int i, ret = 0;
602 bool is_return = false, is_delete = false;
603 char *symbol = NULL, *event = NULL, *group = NULL;
604 char *arg;
605 unsigned long offset = 0;
606 void *addr = NULL;
607 char buf[MAX_EVENT_NAME_LEN];
608
609 /* argc must be >= 1 */
610 if (argv[0][0] == 'p')
611 is_return = false;
612 else if (argv[0][0] == 'r')
613 is_return = true;
614 else if (argv[0][0] == '-')
615 is_delete = true;
616 else {
617 pr_info("Probe definition must be started with 'p', 'r' or"
618 " '-'.\n");
619 return -EINVAL;
620 }
621
622 if (argv[0][1] == ':') {
623 event = &argv[0][2];
624 if (strchr(event, '/')) {
625 group = event;
626 event = strchr(group, '/') + 1;
627 event[-1] = '\0';
628 if (strlen(group) == 0) {
629 pr_info("Group name is not specified\n");
630 return -EINVAL;
631 }
632 }
633 if (strlen(event) == 0) {
634 pr_info("Event name is not specified\n");
635 return -EINVAL;
636 }
637 }
638 if (!group)
639 group = KPROBE_EVENT_SYSTEM;
640
641 if (is_delete) {
642 if (!event) {
643 pr_info("Delete command needs an event name.\n");
644 return -EINVAL;
645 }
646 mutex_lock(&probe_lock);
647 tk = find_trace_kprobe(event, group);
648 if (!tk) {
649 mutex_unlock(&probe_lock);
650 pr_info("Event %s/%s doesn't exist.\n", group, event);
651 return -ENOENT;
652 }
653 /* delete an event */
654 ret = unregister_trace_kprobe(tk);
655 if (ret == 0)
656 free_trace_kprobe(tk);
657 mutex_unlock(&probe_lock);
658 return ret;
659 }
660
661 if (argc < 2) {
662 pr_info("Probe point is not specified.\n");
663 return -EINVAL;
664 }
665 if (isdigit(argv[1][0])) {
666 if (is_return) {
667 pr_info("Return probe point must be a symbol.\n");
668 return -EINVAL;
669 }
670 /* an address specified */
671 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
672 if (ret) {
673 pr_info("Failed to parse address.\n");
674 return ret;
675 }
676 } else {
677 /* a symbol specified */
678 symbol = argv[1];
679 /* TODO: support .init module functions */
680 ret = traceprobe_split_symbol_offset(symbol, &offset);
681 if (ret) {
682 pr_info("Failed to parse symbol.\n");
683 return ret;
684 }
685 if (offset && is_return) {
686 pr_info("Return probe must be used without offset.\n");
687 return -EINVAL;
688 }
689 }
690 argc -= 2; argv += 2;
691
692 /* setup a probe */
693 if (!event) {
694 /* Make a new event name */
695 if (symbol)
696 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
697 is_return ? 'r' : 'p', symbol, offset);
698 else
699 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
700 is_return ? 'r' : 'p', addr);
701 event = buf;
702 }
703 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
704 is_return);
705 if (IS_ERR(tk)) {
706 pr_info("Failed to allocate trace_probe.(%d)\n",
707 (int)PTR_ERR(tk));
708 return PTR_ERR(tk);
709 }
710
711 /* parse arguments */
712 ret = 0;
713 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
714 struct probe_arg *parg = &tk->tp.args[i];
715
716 /* Increment count for freeing args in error case */
717 tk->tp.nr_args++;
718
719 /* Parse argument name */
720 arg = strchr(argv[i], '=');
721 if (arg) {
722 *arg++ = '\0';
723 parg->name = kstrdup(argv[i], GFP_KERNEL);
724 } else {
725 arg = argv[i];
726 /* If argument name is omitted, set "argN" */
727 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
728 parg->name = kstrdup(buf, GFP_KERNEL);
729 }
730
731 if (!parg->name) {
732 pr_info("Failed to allocate argument[%d] name.\n", i);
733 ret = -ENOMEM;
734 goto error;
735 }
736
737 if (!is_good_name(parg->name)) {
738 pr_info("Invalid argument[%d] name: %s\n",
739 i, parg->name);
740 ret = -EINVAL;
741 goto error;
742 }
743
744 if (traceprobe_conflict_field_name(parg->name,
745 tk->tp.args, i)) {
746 pr_info("Argument[%d] name '%s' conflicts with "
747 "another field.\n", i, argv[i]);
748 ret = -EINVAL;
749 goto error;
750 }
751
752 /* Parse fetch argument */
753 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
754 is_return, true,
755 kprobes_fetch_type_table);
756 if (ret) {
757 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
758 goto error;
759 }
760 }
761
762 ret = register_trace_kprobe(tk);
763 if (ret)
764 goto error;
765 return 0;
766
767error:
768 free_trace_kprobe(tk);
769 return ret;
770}
771
772static int release_all_trace_kprobes(void)
773{
774 struct trace_kprobe *tk;
775 int ret = 0;
776
777 mutex_lock(&probe_lock);
778 /* Ensure no probe is in use. */
779 list_for_each_entry(tk, &probe_list, list)
780 if (trace_probe_is_enabled(&tk->tp)) {
781 ret = -EBUSY;
782 goto end;
783 }
784 /* TODO: Use batch unregistration */
785 while (!list_empty(&probe_list)) {
786 tk = list_entry(probe_list.next, struct trace_kprobe, list);
787 ret = unregister_trace_kprobe(tk);
788 if (ret)
789 goto end;
790 free_trace_kprobe(tk);
791 }
792
793end:
794 mutex_unlock(&probe_lock);
795
796 return ret;
797}
798
799/* Probes listing interfaces */
800static void *probes_seq_start(struct seq_file *m, loff_t *pos)
801{
802 mutex_lock(&probe_lock);
803 return seq_list_start(&probe_list, *pos);
804}
805
806static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
807{
808 return seq_list_next(v, &probe_list, pos);
809}
810
811static void probes_seq_stop(struct seq_file *m, void *v)
812{
813 mutex_unlock(&probe_lock);
814}
815
816static int probes_seq_show(struct seq_file *m, void *v)
817{
818 struct trace_kprobe *tk = v;
819 int i;
820
821 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
822 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
823 trace_event_name(&tk->tp.call));
824
825 if (!tk->symbol)
826 seq_printf(m, " 0x%p", tk->rp.kp.addr);
827 else if (tk->rp.kp.offset)
828 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
829 tk->rp.kp.offset);
830 else
831 seq_printf(m, " %s", trace_kprobe_symbol(tk));
832
833 for (i = 0; i < tk->tp.nr_args; i++)
834 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
835 seq_putc(m, '\n');
836
837 return 0;
838}
839
840static const struct seq_operations probes_seq_op = {
841 .start = probes_seq_start,
842 .next = probes_seq_next,
843 .stop = probes_seq_stop,
844 .show = probes_seq_show
845};
846
847static int probes_open(struct inode *inode, struct file *file)
848{
849 int ret;
850
851 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
852 ret = release_all_trace_kprobes();
853 if (ret < 0)
854 return ret;
855 }
856
857 return seq_open(file, &probes_seq_op);
858}
859
860static ssize_t probes_write(struct file *file, const char __user *buffer,
861 size_t count, loff_t *ppos)
862{
863 return traceprobe_probes_write(file, buffer, count, ppos,
864 create_trace_kprobe);
865}
866
867static const struct file_operations kprobe_events_ops = {
868 .owner = THIS_MODULE,
869 .open = probes_open,
870 .read = seq_read,
871 .llseek = seq_lseek,
872 .release = seq_release,
873 .write = probes_write,
874};
875
876/* Probes profiling interfaces */
877static int probes_profile_seq_show(struct seq_file *m, void *v)
878{
879 struct trace_kprobe *tk = v;
880 unsigned long nhit = 0;
881 int cpu;
882
883 for_each_possible_cpu(cpu)
884 nhit += *per_cpu_ptr(tk->nhit, cpu);
885
886 seq_printf(m, " %-44s %15lu %15lu\n",
887 trace_event_name(&tk->tp.call), nhit,
888 tk->rp.kp.nmissed);
889
890 return 0;
891}
892
893static const struct seq_operations profile_seq_op = {
894 .start = probes_seq_start,
895 .next = probes_seq_next,
896 .stop = probes_seq_stop,
897 .show = probes_profile_seq_show
898};
899
900static int profile_open(struct inode *inode, struct file *file)
901{
902 return seq_open(file, &profile_seq_op);
903}
904
905static const struct file_operations kprobe_profile_ops = {
906 .owner = THIS_MODULE,
907 .open = profile_open,
908 .read = seq_read,
909 .llseek = seq_lseek,
910 .release = seq_release,
911};
912
913/* Kprobe handler */
914static nokprobe_inline void
915__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
916 struct trace_event_file *trace_file)
917{
918 struct kprobe_trace_entry_head *entry;
919 struct ring_buffer_event *event;
920 struct ring_buffer *buffer;
921 int size, dsize, pc;
922 unsigned long irq_flags;
923 struct trace_event_call *call = &tk->tp.call;
924
925 WARN_ON(call != trace_file->event_call);
926
927 if (trace_trigger_soft_disabled(trace_file))
928 return;
929
930 local_save_flags(irq_flags);
931 pc = preempt_count();
932
933 dsize = __get_data_size(&tk->tp, regs);
934 size = sizeof(*entry) + tk->tp.size + dsize;
935
936 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
937 call->event.type,
938 size, irq_flags, pc);
939 if (!event)
940 return;
941
942 entry = ring_buffer_event_data(event);
943 entry->ip = (unsigned long)tk->rp.kp.addr;
944 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
945
946 event_trigger_unlock_commit_regs(trace_file, buffer, event,
947 entry, irq_flags, pc, regs);
948}
949
950static void
951kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
952{
953 struct event_file_link *link;
954
955 list_for_each_entry_rcu(link, &tk->tp.files, list)
956 __kprobe_trace_func(tk, regs, link->file);
957}
958NOKPROBE_SYMBOL(kprobe_trace_func);
959
960/* Kretprobe handler */
961static nokprobe_inline void
962__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
963 struct pt_regs *regs,
964 struct trace_event_file *trace_file)
965{
966 struct kretprobe_trace_entry_head *entry;
967 struct ring_buffer_event *event;
968 struct ring_buffer *buffer;
969 int size, pc, dsize;
970 unsigned long irq_flags;
971 struct trace_event_call *call = &tk->tp.call;
972
973 WARN_ON(call != trace_file->event_call);
974
975 if (trace_trigger_soft_disabled(trace_file))
976 return;
977
978 local_save_flags(irq_flags);
979 pc = preempt_count();
980
981 dsize = __get_data_size(&tk->tp, regs);
982 size = sizeof(*entry) + tk->tp.size + dsize;
983
984 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
985 call->event.type,
986 size, irq_flags, pc);
987 if (!event)
988 return;
989
990 entry = ring_buffer_event_data(event);
991 entry->func = (unsigned long)tk->rp.kp.addr;
992 entry->ret_ip = (unsigned long)ri->ret_addr;
993 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
994
995 event_trigger_unlock_commit_regs(trace_file, buffer, event,
996 entry, irq_flags, pc, regs);
997}
998
999static void
1000kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1001 struct pt_regs *regs)
1002{
1003 struct event_file_link *link;
1004
1005 list_for_each_entry_rcu(link, &tk->tp.files, list)
1006 __kretprobe_trace_func(tk, ri, regs, link->file);
1007}
1008NOKPROBE_SYMBOL(kretprobe_trace_func);
1009
1010/* Event entry printers */
1011static enum print_line_t
1012print_kprobe_event(struct trace_iterator *iter, int flags,
1013 struct trace_event *event)
1014{
1015 struct kprobe_trace_entry_head *field;
1016 struct trace_seq *s = &iter->seq;
1017 struct trace_probe *tp;
1018 u8 *data;
1019 int i;
1020
1021 field = (struct kprobe_trace_entry_head *)iter->ent;
1022 tp = container_of(event, struct trace_probe, call.event);
1023
1024 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1025
1026 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1027 goto out;
1028
1029 trace_seq_putc(s, ')');
1030
1031 data = (u8 *)&field[1];
1032 for (i = 0; i < tp->nr_args; i++)
1033 if (!tp->args[i].type->print(s, tp->args[i].name,
1034 data + tp->args[i].offset, field))
1035 goto out;
1036
1037 trace_seq_putc(s, '\n');
1038 out:
1039 return trace_handle_return(s);
1040}
1041
1042static enum print_line_t
1043print_kretprobe_event(struct trace_iterator *iter, int flags,
1044 struct trace_event *event)
1045{
1046 struct kretprobe_trace_entry_head *field;
1047 struct trace_seq *s = &iter->seq;
1048 struct trace_probe *tp;
1049 u8 *data;
1050 int i;
1051
1052 field = (struct kretprobe_trace_entry_head *)iter->ent;
1053 tp = container_of(event, struct trace_probe, call.event);
1054
1055 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1056
1057 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1058 goto out;
1059
1060 trace_seq_puts(s, " <- ");
1061
1062 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1063 goto out;
1064
1065 trace_seq_putc(s, ')');
1066
1067 data = (u8 *)&field[1];
1068 for (i = 0; i < tp->nr_args; i++)
1069 if (!tp->args[i].type->print(s, tp->args[i].name,
1070 data + tp->args[i].offset, field))
1071 goto out;
1072
1073 trace_seq_putc(s, '\n');
1074
1075 out:
1076 return trace_handle_return(s);
1077}
1078
1079
1080static int kprobe_event_define_fields(struct trace_event_call *event_call)
1081{
1082 int ret, i;
1083 struct kprobe_trace_entry_head field;
1084 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1085
1086 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1087 /* Set argument names as fields */
1088 for (i = 0; i < tk->tp.nr_args; i++) {
1089 struct probe_arg *parg = &tk->tp.args[i];
1090
1091 ret = trace_define_field(event_call, parg->type->fmttype,
1092 parg->name,
1093 sizeof(field) + parg->offset,
1094 parg->type->size,
1095 parg->type->is_signed,
1096 FILTER_OTHER);
1097 if (ret)
1098 return ret;
1099 }
1100 return 0;
1101}
1102
1103static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1104{
1105 int ret, i;
1106 struct kretprobe_trace_entry_head field;
1107 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1108
1109 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1110 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1111 /* Set argument names as fields */
1112 for (i = 0; i < tk->tp.nr_args; i++) {
1113 struct probe_arg *parg = &tk->tp.args[i];
1114
1115 ret = trace_define_field(event_call, parg->type->fmttype,
1116 parg->name,
1117 sizeof(field) + parg->offset,
1118 parg->type->size,
1119 parg->type->is_signed,
1120 FILTER_OTHER);
1121 if (ret)
1122 return ret;
1123 }
1124 return 0;
1125}
1126
1127#ifdef CONFIG_PERF_EVENTS
1128
1129/* Kprobe profile handler */
1130static void
1131kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1132{
1133 struct trace_event_call *call = &tk->tp.call;
1134 struct bpf_prog *prog = call->prog;
1135 struct kprobe_trace_entry_head *entry;
1136 struct hlist_head *head;
1137 int size, __size, dsize;
1138 int rctx;
1139
1140 if (prog && !trace_call_bpf(prog, regs))
1141 return;
1142
1143 head = this_cpu_ptr(call->perf_events);
1144 if (hlist_empty(head))
1145 return;
1146
1147 dsize = __get_data_size(&tk->tp, regs);
1148 __size = sizeof(*entry) + tk->tp.size + dsize;
1149 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1150 size -= sizeof(u32);
1151
1152 entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1153 if (!entry)
1154 return;
1155
1156 entry->ip = (unsigned long)tk->rp.kp.addr;
1157 memset(&entry[1], 0, dsize);
1158 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1159 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1160}
1161NOKPROBE_SYMBOL(kprobe_perf_func);
1162
1163/* Kretprobe profile handler */
1164static void
1165kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1166 struct pt_regs *regs)
1167{
1168 struct trace_event_call *call = &tk->tp.call;
1169 struct bpf_prog *prog = call->prog;
1170 struct kretprobe_trace_entry_head *entry;
1171 struct hlist_head *head;
1172 int size, __size, dsize;
1173 int rctx;
1174
1175 if (prog && !trace_call_bpf(prog, regs))
1176 return;
1177
1178 head = this_cpu_ptr(call->perf_events);
1179 if (hlist_empty(head))
1180 return;
1181
1182 dsize = __get_data_size(&tk->tp, regs);
1183 __size = sizeof(*entry) + tk->tp.size + dsize;
1184 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1185 size -= sizeof(u32);
1186
1187 entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1188 if (!entry)
1189 return;
1190
1191 entry->func = (unsigned long)tk->rp.kp.addr;
1192 entry->ret_ip = (unsigned long)ri->ret_addr;
1193 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1194 perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1195}
1196NOKPROBE_SYMBOL(kretprobe_perf_func);
1197#endif /* CONFIG_PERF_EVENTS */
1198
1199/*
1200 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1201 *
1202 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1203 * lockless, but we can't race with this __init function.
1204 */
1205static int kprobe_register(struct trace_event_call *event,
1206 enum trace_reg type, void *data)
1207{
1208 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1209 struct trace_event_file *file = data;
1210
1211 switch (type) {
1212 case TRACE_REG_REGISTER:
1213 return enable_trace_kprobe(tk, file);
1214 case TRACE_REG_UNREGISTER:
1215 return disable_trace_kprobe(tk, file);
1216
1217#ifdef CONFIG_PERF_EVENTS
1218 case TRACE_REG_PERF_REGISTER:
1219 return enable_trace_kprobe(tk, NULL);
1220 case TRACE_REG_PERF_UNREGISTER:
1221 return disable_trace_kprobe(tk, NULL);
1222 case TRACE_REG_PERF_OPEN:
1223 case TRACE_REG_PERF_CLOSE:
1224 case TRACE_REG_PERF_ADD:
1225 case TRACE_REG_PERF_DEL:
1226 return 0;
1227#endif
1228 }
1229 return 0;
1230}
1231
1232static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1233{
1234 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1235
1236 raw_cpu_inc(*tk->nhit);
1237
1238 if (tk->tp.flags & TP_FLAG_TRACE)
1239 kprobe_trace_func(tk, regs);
1240#ifdef CONFIG_PERF_EVENTS
1241 if (tk->tp.flags & TP_FLAG_PROFILE)
1242 kprobe_perf_func(tk, regs);
1243#endif
1244 return 0; /* We don't tweek kernel, so just return 0 */
1245}
1246NOKPROBE_SYMBOL(kprobe_dispatcher);
1247
1248static int
1249kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1250{
1251 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1252
1253 raw_cpu_inc(*tk->nhit);
1254
1255 if (tk->tp.flags & TP_FLAG_TRACE)
1256 kretprobe_trace_func(tk, ri, regs);
1257#ifdef CONFIG_PERF_EVENTS
1258 if (tk->tp.flags & TP_FLAG_PROFILE)
1259 kretprobe_perf_func(tk, ri, regs);
1260#endif
1261 return 0; /* We don't tweek kernel, so just return 0 */
1262}
1263NOKPROBE_SYMBOL(kretprobe_dispatcher);
1264
1265static struct trace_event_functions kretprobe_funcs = {
1266 .trace = print_kretprobe_event
1267};
1268
1269static struct trace_event_functions kprobe_funcs = {
1270 .trace = print_kprobe_event
1271};
1272
1273static int register_kprobe_event(struct trace_kprobe *tk)
1274{
1275 struct trace_event_call *call = &tk->tp.call;
1276 int ret;
1277
1278 /* Initialize trace_event_call */
1279 INIT_LIST_HEAD(&call->class->fields);
1280 if (trace_kprobe_is_return(tk)) {
1281 call->event.funcs = &kretprobe_funcs;
1282 call->class->define_fields = kretprobe_event_define_fields;
1283 } else {
1284 call->event.funcs = &kprobe_funcs;
1285 call->class->define_fields = kprobe_event_define_fields;
1286 }
1287 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1288 return -ENOMEM;
1289 ret = register_trace_event(&call->event);
1290 if (!ret) {
1291 kfree(call->print_fmt);
1292 return -ENODEV;
1293 }
1294 call->flags = TRACE_EVENT_FL_KPROBE;
1295 call->class->reg = kprobe_register;
1296 call->data = tk;
1297 ret = trace_add_event_call(call);
1298 if (ret) {
1299 pr_info("Failed to register kprobe event: %s\n",
1300 trace_event_name(call));
1301 kfree(call->print_fmt);
1302 unregister_trace_event(&call->event);
1303 }
1304 return ret;
1305}
1306
1307static int unregister_kprobe_event(struct trace_kprobe *tk)
1308{
1309 int ret;
1310
1311 /* tp->event is unregistered in trace_remove_event_call() */
1312 ret = trace_remove_event_call(&tk->tp.call);
1313 if (!ret)
1314 kfree(tk->tp.call.print_fmt);
1315 return ret;
1316}
1317
1318/* Make a tracefs interface for controlling probe points */
1319static __init int init_kprobe_trace(void)
1320{
1321 struct dentry *d_tracer;
1322 struct dentry *entry;
1323
1324 if (register_module_notifier(&trace_kprobe_module_nb))
1325 return -EINVAL;
1326
1327 d_tracer = tracing_init_dentry();
1328 if (IS_ERR(d_tracer))
1329 return 0;
1330
1331 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1332 NULL, &kprobe_events_ops);
1333
1334 /* Event list interface */
1335 if (!entry)
1336 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1337
1338 /* Profile interface */
1339 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1340 NULL, &kprobe_profile_ops);
1341
1342 if (!entry)
1343 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1344 return 0;
1345}
1346fs_initcall(init_kprobe_trace);
1347
1348
1349#ifdef CONFIG_FTRACE_STARTUP_TEST
1350
1351/*
1352 * The "__used" keeps gcc from removing the function symbol
1353 * from the kallsyms table.
1354 */
1355static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1356 int a4, int a5, int a6)
1357{
1358 return a1 + a2 + a3 + a4 + a5 + a6;
1359}
1360
1361static struct trace_event_file *
1362find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1363{
1364 struct trace_event_file *file;
1365
1366 list_for_each_entry(file, &tr->events, list)
1367 if (file->event_call == &tk->tp.call)
1368 return file;
1369
1370 return NULL;
1371}
1372
1373/*
1374 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1375 * stage, we can do this lockless.
1376 */
1377static __init int kprobe_trace_self_tests_init(void)
1378{
1379 int ret, warn = 0;
1380 int (*target)(int, int, int, int, int, int);
1381 struct trace_kprobe *tk;
1382 struct trace_event_file *file;
1383
1384 if (tracing_is_disabled())
1385 return -ENODEV;
1386
1387 target = kprobe_trace_selftest_target;
1388
1389 pr_info("Testing kprobe tracing: ");
1390
1391 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1392 "$stack $stack0 +0($stack)",
1393 create_trace_kprobe);
1394 if (WARN_ON_ONCE(ret)) {
1395 pr_warn("error on probing function entry.\n");
1396 warn++;
1397 } else {
1398 /* Enable trace point */
1399 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1400 if (WARN_ON_ONCE(tk == NULL)) {
1401 pr_warn("error on getting new probe.\n");
1402 warn++;
1403 } else {
1404 file = find_trace_probe_file(tk, top_trace_array());
1405 if (WARN_ON_ONCE(file == NULL)) {
1406 pr_warn("error on getting probe file.\n");
1407 warn++;
1408 } else
1409 enable_trace_kprobe(tk, file);
1410 }
1411 }
1412
1413 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1414 "$retval", create_trace_kprobe);
1415 if (WARN_ON_ONCE(ret)) {
1416 pr_warn("error on probing function return.\n");
1417 warn++;
1418 } else {
1419 /* Enable trace point */
1420 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1421 if (WARN_ON_ONCE(tk == NULL)) {
1422 pr_warn("error on getting 2nd new probe.\n");
1423 warn++;
1424 } else {
1425 file = find_trace_probe_file(tk, top_trace_array());
1426 if (WARN_ON_ONCE(file == NULL)) {
1427 pr_warn("error on getting probe file.\n");
1428 warn++;
1429 } else
1430 enable_trace_kprobe(tk, file);
1431 }
1432 }
1433
1434 if (warn)
1435 goto end;
1436
1437 ret = target(1, 2, 3, 4, 5, 6);
1438
1439 /* Disable trace points before removing it */
1440 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1441 if (WARN_ON_ONCE(tk == NULL)) {
1442 pr_warn("error on getting test probe.\n");
1443 warn++;
1444 } else {
1445 file = find_trace_probe_file(tk, top_trace_array());
1446 if (WARN_ON_ONCE(file == NULL)) {
1447 pr_warn("error on getting probe file.\n");
1448 warn++;
1449 } else
1450 disable_trace_kprobe(tk, file);
1451 }
1452
1453 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1454 if (WARN_ON_ONCE(tk == NULL)) {
1455 pr_warn("error on getting 2nd test probe.\n");
1456 warn++;
1457 } else {
1458 file = find_trace_probe_file(tk, top_trace_array());
1459 if (WARN_ON_ONCE(file == NULL)) {
1460 pr_warn("error on getting probe file.\n");
1461 warn++;
1462 } else
1463 disable_trace_kprobe(tk, file);
1464 }
1465
1466 ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1467 if (WARN_ON_ONCE(ret)) {
1468 pr_warn("error on deleting a probe.\n");
1469 warn++;
1470 }
1471
1472 ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1473 if (WARN_ON_ONCE(ret)) {
1474 pr_warn("error on deleting a probe.\n");
1475 warn++;
1476 }
1477
1478end:
1479 release_all_trace_kprobes();
1480 if (warn)
1481 pr_cont("NG: Some tests are failed. Please check them.\n");
1482 else
1483 pr_cont("OK\n");
1484 return 0;
1485}
1486
1487late_initcall(kprobe_trace_self_tests_init);
1488
1489#endif
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/bpf-cgroup.h>
11#include <linux/security.h>
12#include <linux/module.h>
13#include <linux/uaccess.h>
14#include <linux/rculist.h>
15#include <linux/error-injection.h>
16
17#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
18
19#include "trace_dynevent.h"
20#include "trace_kprobe_selftest.h"
21#include "trace_probe.h"
22#include "trace_probe_tmpl.h"
23#include "trace_probe_kernel.h"
24
25#define KPROBE_EVENT_SYSTEM "kprobes"
26#define KRETPROBE_MAXACTIVE_MAX 4096
27
28/* Kprobe early definition from command line */
29static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
30
31static int __init set_kprobe_boot_events(char *str)
32{
33 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
34 disable_tracing_selftest("running kprobe events");
35
36 return 1;
37}
38__setup("kprobe_event=", set_kprobe_boot_events);
39
40static int trace_kprobe_create(const char *raw_command);
41static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
42static int trace_kprobe_release(struct dyn_event *ev);
43static bool trace_kprobe_is_busy(struct dyn_event *ev);
44static bool trace_kprobe_match(const char *system, const char *event,
45 int argc, const char **argv, struct dyn_event *ev);
46
47static struct dyn_event_operations trace_kprobe_ops = {
48 .create = trace_kprobe_create,
49 .show = trace_kprobe_show,
50 .is_busy = trace_kprobe_is_busy,
51 .free = trace_kprobe_release,
52 .match = trace_kprobe_match,
53};
54
55/*
56 * Kprobe event core functions
57 */
58struct trace_kprobe {
59 struct dyn_event devent;
60 struct kretprobe rp; /* Use rp.kp for kprobe use */
61 unsigned long __percpu *nhit;
62 const char *symbol; /* symbol name */
63 struct trace_probe tp;
64};
65
66static bool is_trace_kprobe(struct dyn_event *ev)
67{
68 return ev->ops == &trace_kprobe_ops;
69}
70
71static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
72{
73 return container_of(ev, struct trace_kprobe, devent);
74}
75
76/**
77 * for_each_trace_kprobe - iterate over the trace_kprobe list
78 * @pos: the struct trace_kprobe * for each entry
79 * @dpos: the struct dyn_event * to use as a loop cursor
80 */
81#define for_each_trace_kprobe(pos, dpos) \
82 for_each_dyn_event(dpos) \
83 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
84
85static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
86{
87 return tk->rp.handler != NULL;
88}
89
90static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
91{
92 return tk->symbol ? tk->symbol : "unknown";
93}
94
95static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
96{
97 return tk->rp.kp.offset;
98}
99
100static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
101{
102 return kprobe_gone(&tk->rp.kp);
103}
104
105static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
106 struct module *mod)
107{
108 int len = strlen(module_name(mod));
109 const char *name = trace_kprobe_symbol(tk);
110
111 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
112}
113
114#ifdef CONFIG_MODULES
115static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
116{
117 char *p;
118 bool ret;
119
120 if (!tk->symbol)
121 return false;
122 p = strchr(tk->symbol, ':');
123 if (!p)
124 return true;
125 *p = '\0';
126 rcu_read_lock_sched();
127 ret = !!find_module(tk->symbol);
128 rcu_read_unlock_sched();
129 *p = ':';
130
131 return ret;
132}
133#else
134static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
135{
136 return false;
137}
138#endif
139
140static bool trace_kprobe_is_busy(struct dyn_event *ev)
141{
142 struct trace_kprobe *tk = to_trace_kprobe(ev);
143
144 return trace_probe_is_enabled(&tk->tp);
145}
146
147static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
148 int argc, const char **argv)
149{
150 char buf[MAX_ARGSTR_LEN + 1];
151
152 if (!argc)
153 return true;
154
155 if (!tk->symbol)
156 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
157 else if (tk->rp.kp.offset)
158 snprintf(buf, sizeof(buf), "%s+%u",
159 trace_kprobe_symbol(tk), tk->rp.kp.offset);
160 else
161 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
162 if (strcmp(buf, argv[0]))
163 return false;
164 argc--; argv++;
165
166 return trace_probe_match_command_args(&tk->tp, argc, argv);
167}
168
169static bool trace_kprobe_match(const char *system, const char *event,
170 int argc, const char **argv, struct dyn_event *ev)
171{
172 struct trace_kprobe *tk = to_trace_kprobe(ev);
173
174 return (event[0] == '\0' ||
175 strcmp(trace_probe_name(&tk->tp), event) == 0) &&
176 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
177 trace_kprobe_match_command_head(tk, argc, argv);
178}
179
180static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
181{
182 unsigned long nhit = 0;
183 int cpu;
184
185 for_each_possible_cpu(cpu)
186 nhit += *per_cpu_ptr(tk->nhit, cpu);
187
188 return nhit;
189}
190
191static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
192{
193 return !(list_empty(&tk->rp.kp.list) &&
194 hlist_unhashed(&tk->rp.kp.hlist));
195}
196
197/* Return 0 if it fails to find the symbol address */
198static nokprobe_inline
199unsigned long trace_kprobe_address(struct trace_kprobe *tk)
200{
201 unsigned long addr;
202
203 if (tk->symbol) {
204 addr = (unsigned long)
205 kallsyms_lookup_name(trace_kprobe_symbol(tk));
206 if (addr)
207 addr += tk->rp.kp.offset;
208 } else {
209 addr = (unsigned long)tk->rp.kp.addr;
210 }
211 return addr;
212}
213
214static nokprobe_inline struct trace_kprobe *
215trace_kprobe_primary_from_call(struct trace_event_call *call)
216{
217 struct trace_probe *tp;
218
219 tp = trace_probe_primary_from_call(call);
220 if (WARN_ON_ONCE(!tp))
221 return NULL;
222
223 return container_of(tp, struct trace_kprobe, tp);
224}
225
226bool trace_kprobe_on_func_entry(struct trace_event_call *call)
227{
228 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
229
230 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
231 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
232 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
233}
234
235bool trace_kprobe_error_injectable(struct trace_event_call *call)
236{
237 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
238
239 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
240 false;
241}
242
243static int register_kprobe_event(struct trace_kprobe *tk);
244static int unregister_kprobe_event(struct trace_kprobe *tk);
245
246static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
247static int kretprobe_dispatcher(struct kretprobe_instance *ri,
248 struct pt_regs *regs);
249
250static void free_trace_kprobe(struct trace_kprobe *tk)
251{
252 if (tk) {
253 trace_probe_cleanup(&tk->tp);
254 kfree(tk->symbol);
255 free_percpu(tk->nhit);
256 kfree(tk);
257 }
258}
259
260/*
261 * Allocate new trace_probe and initialize it (including kprobes).
262 */
263static struct trace_kprobe *alloc_trace_kprobe(const char *group,
264 const char *event,
265 void *addr,
266 const char *symbol,
267 unsigned long offs,
268 int maxactive,
269 int nargs, bool is_return)
270{
271 struct trace_kprobe *tk;
272 int ret = -ENOMEM;
273
274 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
275 if (!tk)
276 return ERR_PTR(ret);
277
278 tk->nhit = alloc_percpu(unsigned long);
279 if (!tk->nhit)
280 goto error;
281
282 if (symbol) {
283 tk->symbol = kstrdup(symbol, GFP_KERNEL);
284 if (!tk->symbol)
285 goto error;
286 tk->rp.kp.symbol_name = tk->symbol;
287 tk->rp.kp.offset = offs;
288 } else
289 tk->rp.kp.addr = addr;
290
291 if (is_return)
292 tk->rp.handler = kretprobe_dispatcher;
293 else
294 tk->rp.kp.pre_handler = kprobe_dispatcher;
295
296 tk->rp.maxactive = maxactive;
297 INIT_HLIST_NODE(&tk->rp.kp.hlist);
298 INIT_LIST_HEAD(&tk->rp.kp.list);
299
300 ret = trace_probe_init(&tk->tp, event, group, false, nargs);
301 if (ret < 0)
302 goto error;
303
304 dyn_event_init(&tk->devent, &trace_kprobe_ops);
305 return tk;
306error:
307 free_trace_kprobe(tk);
308 return ERR_PTR(ret);
309}
310
311static struct trace_kprobe *find_trace_kprobe(const char *event,
312 const char *group)
313{
314 struct dyn_event *pos;
315 struct trace_kprobe *tk;
316
317 for_each_trace_kprobe(tk, pos)
318 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
319 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
320 return tk;
321 return NULL;
322}
323
324static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
325{
326 int ret = 0;
327
328 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
329 if (trace_kprobe_is_return(tk))
330 ret = enable_kretprobe(&tk->rp);
331 else
332 ret = enable_kprobe(&tk->rp.kp);
333 }
334
335 return ret;
336}
337
338static void __disable_trace_kprobe(struct trace_probe *tp)
339{
340 struct trace_kprobe *tk;
341
342 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
343 if (!trace_kprobe_is_registered(tk))
344 continue;
345 if (trace_kprobe_is_return(tk))
346 disable_kretprobe(&tk->rp);
347 else
348 disable_kprobe(&tk->rp.kp);
349 }
350}
351
352/*
353 * Enable trace_probe
354 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
355 */
356static int enable_trace_kprobe(struct trace_event_call *call,
357 struct trace_event_file *file)
358{
359 struct trace_probe *tp;
360 struct trace_kprobe *tk;
361 bool enabled;
362 int ret = 0;
363
364 tp = trace_probe_primary_from_call(call);
365 if (WARN_ON_ONCE(!tp))
366 return -ENODEV;
367 enabled = trace_probe_is_enabled(tp);
368
369 /* This also changes "enabled" state */
370 if (file) {
371 ret = trace_probe_add_file(tp, file);
372 if (ret)
373 return ret;
374 } else
375 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
376
377 if (enabled)
378 return 0;
379
380 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
381 if (trace_kprobe_has_gone(tk))
382 continue;
383 ret = __enable_trace_kprobe(tk);
384 if (ret)
385 break;
386 enabled = true;
387 }
388
389 if (ret) {
390 /* Failed to enable one of them. Roll back all */
391 if (enabled)
392 __disable_trace_kprobe(tp);
393 if (file)
394 trace_probe_remove_file(tp, file);
395 else
396 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
397 }
398
399 return ret;
400}
401
402/*
403 * Disable trace_probe
404 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
405 */
406static int disable_trace_kprobe(struct trace_event_call *call,
407 struct trace_event_file *file)
408{
409 struct trace_probe *tp;
410
411 tp = trace_probe_primary_from_call(call);
412 if (WARN_ON_ONCE(!tp))
413 return -ENODEV;
414
415 if (file) {
416 if (!trace_probe_get_file_link(tp, file))
417 return -ENOENT;
418 if (!trace_probe_has_single_file(tp))
419 goto out;
420 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
421 } else
422 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
423
424 if (!trace_probe_is_enabled(tp))
425 __disable_trace_kprobe(tp);
426
427 out:
428 if (file)
429 /*
430 * Synchronization is done in below function. For perf event,
431 * file == NULL and perf_trace_event_unreg() calls
432 * tracepoint_synchronize_unregister() to ensure synchronize
433 * event. We don't need to care about it.
434 */
435 trace_probe_remove_file(tp, file);
436
437 return 0;
438}
439
440#if defined(CONFIG_DYNAMIC_FTRACE) && \
441 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
442static bool __within_notrace_func(unsigned long addr)
443{
444 unsigned long offset, size;
445
446 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
447 return false;
448
449 /* Get the entry address of the target function */
450 addr -= offset;
451
452 /*
453 * Since ftrace_location_range() does inclusive range check, we need
454 * to subtract 1 byte from the end address.
455 */
456 return !ftrace_location_range(addr, addr + size - 1);
457}
458
459static bool within_notrace_func(struct trace_kprobe *tk)
460{
461 unsigned long addr = trace_kprobe_address(tk);
462 char symname[KSYM_NAME_LEN], *p;
463
464 if (!__within_notrace_func(addr))
465 return false;
466
467 /* Check if the address is on a suffixed-symbol */
468 if (!lookup_symbol_name(addr, symname)) {
469 p = strchr(symname, '.');
470 if (!p)
471 return true;
472 *p = '\0';
473 addr = (unsigned long)kprobe_lookup_name(symname, 0);
474 if (addr)
475 return __within_notrace_func(addr);
476 }
477
478 return true;
479}
480#else
481#define within_notrace_func(tk) (false)
482#endif
483
484/* Internal register function - just handle k*probes and flags */
485static int __register_trace_kprobe(struct trace_kprobe *tk)
486{
487 int i, ret;
488
489 ret = security_locked_down(LOCKDOWN_KPROBES);
490 if (ret)
491 return ret;
492
493 if (trace_kprobe_is_registered(tk))
494 return -EINVAL;
495
496 if (within_notrace_func(tk)) {
497 pr_warn("Could not probe notrace function %ps\n",
498 (void *)trace_kprobe_address(tk));
499 return -EINVAL;
500 }
501
502 for (i = 0; i < tk->tp.nr_args; i++) {
503 ret = traceprobe_update_arg(&tk->tp.args[i]);
504 if (ret)
505 return ret;
506 }
507
508 /* Set/clear disabled flag according to tp->flag */
509 if (trace_probe_is_enabled(&tk->tp))
510 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
511 else
512 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
513
514 if (trace_kprobe_is_return(tk))
515 ret = register_kretprobe(&tk->rp);
516 else
517 ret = register_kprobe(&tk->rp.kp);
518
519 return ret;
520}
521
522/* Internal unregister function - just handle k*probes and flags */
523static void __unregister_trace_kprobe(struct trace_kprobe *tk)
524{
525 if (trace_kprobe_is_registered(tk)) {
526 if (trace_kprobe_is_return(tk))
527 unregister_kretprobe(&tk->rp);
528 else
529 unregister_kprobe(&tk->rp.kp);
530 /* Cleanup kprobe for reuse and mark it unregistered */
531 INIT_HLIST_NODE(&tk->rp.kp.hlist);
532 INIT_LIST_HEAD(&tk->rp.kp.list);
533 if (tk->rp.kp.symbol_name)
534 tk->rp.kp.addr = NULL;
535 }
536}
537
538/* Unregister a trace_probe and probe_event */
539static int unregister_trace_kprobe(struct trace_kprobe *tk)
540{
541 /* If other probes are on the event, just unregister kprobe */
542 if (trace_probe_has_sibling(&tk->tp))
543 goto unreg;
544
545 /* Enabled event can not be unregistered */
546 if (trace_probe_is_enabled(&tk->tp))
547 return -EBUSY;
548
549 /* If there's a reference to the dynamic event */
550 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
551 return -EBUSY;
552
553 /* Will fail if probe is being used by ftrace or perf */
554 if (unregister_kprobe_event(tk))
555 return -EBUSY;
556
557unreg:
558 __unregister_trace_kprobe(tk);
559 dyn_event_remove(&tk->devent);
560 trace_probe_unlink(&tk->tp);
561
562 return 0;
563}
564
565static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
566 struct trace_kprobe *comp)
567{
568 struct trace_probe_event *tpe = orig->tp.event;
569 int i;
570
571 list_for_each_entry(orig, &tpe->probes, tp.list) {
572 if (strcmp(trace_kprobe_symbol(orig),
573 trace_kprobe_symbol(comp)) ||
574 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
575 continue;
576
577 /*
578 * trace_probe_compare_arg_type() ensured that nr_args and
579 * each argument name and type are same. Let's compare comm.
580 */
581 for (i = 0; i < orig->tp.nr_args; i++) {
582 if (strcmp(orig->tp.args[i].comm,
583 comp->tp.args[i].comm))
584 break;
585 }
586
587 if (i == orig->tp.nr_args)
588 return true;
589 }
590
591 return false;
592}
593
594static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
595{
596 int ret;
597
598 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
599 if (ret) {
600 /* Note that argument starts index = 2 */
601 trace_probe_log_set_index(ret + 1);
602 trace_probe_log_err(0, DIFF_ARG_TYPE);
603 return -EEXIST;
604 }
605 if (trace_kprobe_has_same_kprobe(to, tk)) {
606 trace_probe_log_set_index(0);
607 trace_probe_log_err(0, SAME_PROBE);
608 return -EEXIST;
609 }
610
611 /* Append to existing event */
612 ret = trace_probe_append(&tk->tp, &to->tp);
613 if (ret)
614 return ret;
615
616 /* Register k*probe */
617 ret = __register_trace_kprobe(tk);
618 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
619 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
620 ret = 0;
621 }
622
623 if (ret)
624 trace_probe_unlink(&tk->tp);
625 else
626 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
627
628 return ret;
629}
630
631/* Register a trace_probe and probe_event */
632static int register_trace_kprobe(struct trace_kprobe *tk)
633{
634 struct trace_kprobe *old_tk;
635 int ret;
636
637 mutex_lock(&event_mutex);
638
639 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
640 trace_probe_group_name(&tk->tp));
641 if (old_tk) {
642 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
643 trace_probe_log_set_index(0);
644 trace_probe_log_err(0, DIFF_PROBE_TYPE);
645 ret = -EEXIST;
646 } else {
647 ret = append_trace_kprobe(tk, old_tk);
648 }
649 goto end;
650 }
651
652 /* Register new event */
653 ret = register_kprobe_event(tk);
654 if (ret) {
655 if (ret == -EEXIST) {
656 trace_probe_log_set_index(0);
657 trace_probe_log_err(0, EVENT_EXIST);
658 } else
659 pr_warn("Failed to register probe event(%d)\n", ret);
660 goto end;
661 }
662
663 /* Register k*probe */
664 ret = __register_trace_kprobe(tk);
665 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
666 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
667 ret = 0;
668 }
669
670 if (ret < 0)
671 unregister_kprobe_event(tk);
672 else
673 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
674
675end:
676 mutex_unlock(&event_mutex);
677 return ret;
678}
679
680#ifdef CONFIG_MODULES
681static int validate_module_probe_symbol(const char *modname, const char *symbol);
682
683static int register_module_trace_kprobe(struct module *mod, struct trace_kprobe *tk)
684{
685 const char *p;
686 int ret = 0;
687
688 p = strchr(trace_kprobe_symbol(tk), ':');
689 if (p)
690 ret = validate_module_probe_symbol(module_name(mod), p + 1);
691 if (!ret)
692 ret = __register_trace_kprobe(tk);
693 return ret;
694}
695
696/* Module notifier call back, checking event on the module */
697static int trace_kprobe_module_callback(struct notifier_block *nb,
698 unsigned long val, void *data)
699{
700 struct module *mod = data;
701 struct dyn_event *pos;
702 struct trace_kprobe *tk;
703 int ret;
704
705 if (val != MODULE_STATE_COMING)
706 return NOTIFY_DONE;
707
708 /* Update probes on coming module */
709 mutex_lock(&event_mutex);
710 for_each_trace_kprobe(tk, pos) {
711 if (trace_kprobe_within_module(tk, mod)) {
712 /* Don't need to check busy - this should have gone. */
713 __unregister_trace_kprobe(tk);
714 ret = register_module_trace_kprobe(mod, tk);
715 if (ret)
716 pr_warn("Failed to re-register probe %s on %s: %d\n",
717 trace_probe_name(&tk->tp),
718 module_name(mod), ret);
719 }
720 }
721 mutex_unlock(&event_mutex);
722
723 return NOTIFY_DONE;
724}
725
726static struct notifier_block trace_kprobe_module_nb = {
727 .notifier_call = trace_kprobe_module_callback,
728 .priority = 2 /* Invoked after kprobe and jump_label module callback */
729};
730static int trace_kprobe_register_module_notifier(void)
731{
732 return register_module_notifier(&trace_kprobe_module_nb);
733}
734#else
735static int trace_kprobe_register_module_notifier(void)
736{
737 return 0;
738}
739#endif /* CONFIG_MODULES */
740
741static int count_symbols(void *data, unsigned long unused)
742{
743 unsigned int *count = data;
744
745 (*count)++;
746
747 return 0;
748}
749
750struct sym_count_ctx {
751 unsigned int count;
752 const char *name;
753};
754
755static int count_mod_symbols(void *data, const char *name, unsigned long unused)
756{
757 struct sym_count_ctx *ctx = data;
758
759 if (strcmp(name, ctx->name) == 0)
760 ctx->count++;
761
762 return 0;
763}
764
765static unsigned int number_of_same_symbols(const char *mod, const char *func_name)
766{
767 struct sym_count_ctx ctx = { .count = 0, .name = func_name };
768
769 if (!mod)
770 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
771
772 module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx);
773
774 return ctx.count;
775}
776
777static int validate_module_probe_symbol(const char *modname, const char *symbol)
778{
779 unsigned int count = number_of_same_symbols(modname, symbol);
780
781 if (count > 1) {
782 /*
783 * Users should use ADDR to remove the ambiguity of
784 * using KSYM only.
785 */
786 return -EADDRNOTAVAIL;
787 } else if (count == 0) {
788 /*
789 * We can return ENOENT earlier than when register the
790 * kprobe.
791 */
792 return -ENOENT;
793 }
794 return 0;
795}
796
797#ifdef CONFIG_MODULES
798/* Return NULL if the module is not loaded or under unloading. */
799static struct module *try_module_get_by_name(const char *name)
800{
801 struct module *mod;
802
803 rcu_read_lock_sched();
804 mod = find_module(name);
805 if (mod && !try_module_get(mod))
806 mod = NULL;
807 rcu_read_unlock_sched();
808
809 return mod;
810}
811#else
812#define try_module_get_by_name(name) (NULL)
813#endif
814
815static int validate_probe_symbol(char *symbol)
816{
817 struct module *mod = NULL;
818 char *modname = NULL, *p;
819 int ret = 0;
820
821 p = strchr(symbol, ':');
822 if (p) {
823 modname = symbol;
824 symbol = p + 1;
825 *p = '\0';
826 mod = try_module_get_by_name(modname);
827 if (!mod)
828 goto out;
829 }
830
831 ret = validate_module_probe_symbol(modname, symbol);
832out:
833 if (p)
834 *p = ':';
835 if (mod)
836 module_put(mod);
837 return ret;
838}
839
840static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
841 struct pt_regs *regs);
842
843static int __trace_kprobe_create(int argc, const char *argv[])
844{
845 /*
846 * Argument syntax:
847 * - Add kprobe:
848 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
849 * - Add kretprobe:
850 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
851 * Or
852 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
853 *
854 * Fetch args:
855 * $retval : fetch return value
856 * $stack : fetch stack address
857 * $stackN : fetch Nth of stack (N:0-)
858 * $comm : fetch current task comm
859 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
860 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
861 * %REG : fetch register REG
862 * Dereferencing memory fetch:
863 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
864 * Alias name of args:
865 * NAME=FETCHARG : set NAME as alias of FETCHARG.
866 * Type of args:
867 * FETCHARG:TYPE : use TYPE instead of unsigned long.
868 */
869 struct trace_kprobe *tk = NULL;
870 int i, len, new_argc = 0, ret = 0;
871 bool is_return = false;
872 char *symbol = NULL, *tmp = NULL;
873 const char **new_argv = NULL;
874 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
875 enum probe_print_type ptype;
876 int maxactive = 0;
877 long offset = 0;
878 void *addr = NULL;
879 char buf[MAX_EVENT_NAME_LEN];
880 char gbuf[MAX_EVENT_NAME_LEN];
881 char abuf[MAX_BTF_ARGS_LEN];
882 char *dbuf = NULL;
883 struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
884
885 switch (argv[0][0]) {
886 case 'r':
887 is_return = true;
888 break;
889 case 'p':
890 break;
891 default:
892 return -ECANCELED;
893 }
894 if (argc < 2)
895 return -ECANCELED;
896
897 trace_probe_log_init("trace_kprobe", argc, argv);
898
899 event = strchr(&argv[0][1], ':');
900 if (event)
901 event++;
902
903 if (isdigit(argv[0][1])) {
904 if (!is_return) {
905 trace_probe_log_err(1, BAD_MAXACT_TYPE);
906 goto parse_error;
907 }
908 if (event)
909 len = event - &argv[0][1] - 1;
910 else
911 len = strlen(&argv[0][1]);
912 if (len > MAX_EVENT_NAME_LEN - 1) {
913 trace_probe_log_err(1, BAD_MAXACT);
914 goto parse_error;
915 }
916 memcpy(buf, &argv[0][1], len);
917 buf[len] = '\0';
918 ret = kstrtouint(buf, 0, &maxactive);
919 if (ret || !maxactive) {
920 trace_probe_log_err(1, BAD_MAXACT);
921 goto parse_error;
922 }
923 /* kretprobes instances are iterated over via a list. The
924 * maximum should stay reasonable.
925 */
926 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
927 trace_probe_log_err(1, MAXACT_TOO_BIG);
928 goto parse_error;
929 }
930 }
931
932 /* try to parse an address. if that fails, try to read the
933 * input as a symbol. */
934 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
935 trace_probe_log_set_index(1);
936 /* Check whether uprobe event specified */
937 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
938 ret = -ECANCELED;
939 goto error;
940 }
941 /* a symbol specified */
942 symbol = kstrdup(argv[1], GFP_KERNEL);
943 if (!symbol) {
944 ret = -ENOMEM;
945 goto error;
946 }
947
948 tmp = strchr(symbol, '%');
949 if (tmp) {
950 if (!strcmp(tmp, "%return")) {
951 *tmp = '\0';
952 is_return = true;
953 } else {
954 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
955 goto parse_error;
956 }
957 }
958
959 /* TODO: support .init module functions */
960 ret = traceprobe_split_symbol_offset(symbol, &offset);
961 if (ret || offset < 0 || offset > UINT_MAX) {
962 trace_probe_log_err(0, BAD_PROBE_ADDR);
963 goto parse_error;
964 }
965 ret = validate_probe_symbol(symbol);
966 if (ret) {
967 if (ret == -EADDRNOTAVAIL)
968 trace_probe_log_err(0, NON_UNIQ_SYMBOL);
969 else
970 trace_probe_log_err(0, BAD_PROBE_ADDR);
971 goto parse_error;
972 }
973 if (is_return)
974 ctx.flags |= TPARG_FL_RETURN;
975 ret = kprobe_on_func_entry(NULL, symbol, offset);
976 if (ret == 0 && !is_return)
977 ctx.flags |= TPARG_FL_FENTRY;
978 /* Defer the ENOENT case until register kprobe */
979 if (ret == -EINVAL && is_return) {
980 trace_probe_log_err(0, BAD_RETPROBE);
981 goto parse_error;
982 }
983 }
984
985 trace_probe_log_set_index(0);
986 if (event) {
987 ret = traceprobe_parse_event_name(&event, &group, gbuf,
988 event - argv[0]);
989 if (ret)
990 goto parse_error;
991 }
992
993 if (!event) {
994 /* Make a new event name */
995 if (symbol)
996 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
997 is_return ? 'r' : 'p', symbol, offset);
998 else
999 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1000 is_return ? 'r' : 'p', addr);
1001 sanitize_event_name(buf);
1002 event = buf;
1003 }
1004
1005 argc -= 2; argv += 2;
1006 ctx.funcname = symbol;
1007 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
1008 abuf, MAX_BTF_ARGS_LEN, &ctx);
1009 if (IS_ERR(new_argv)) {
1010 ret = PTR_ERR(new_argv);
1011 new_argv = NULL;
1012 goto out;
1013 }
1014 if (new_argv) {
1015 argc = new_argc;
1016 argv = new_argv;
1017 }
1018 if (argc > MAX_TRACE_ARGS) {
1019 ret = -E2BIG;
1020 goto out;
1021 }
1022
1023 ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
1024 if (ret)
1025 goto out;
1026
1027 /* setup a probe */
1028 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
1029 argc, is_return);
1030 if (IS_ERR(tk)) {
1031 ret = PTR_ERR(tk);
1032 /* This must return -ENOMEM, else there is a bug */
1033 WARN_ON_ONCE(ret != -ENOMEM);
1034 goto out; /* We know tk is not allocated */
1035 }
1036
1037 /* parse arguments */
1038 for (i = 0; i < argc; i++) {
1039 trace_probe_log_set_index(i + 2);
1040 ctx.offset = 0;
1041 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
1042 if (ret)
1043 goto error; /* This can be -ENOMEM */
1044 }
1045 /* entry handler for kretprobe */
1046 if (is_return && tk->tp.entry_arg) {
1047 tk->rp.entry_handler = trace_kprobe_entry_handler;
1048 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp);
1049 }
1050
1051 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1052 ret = traceprobe_set_print_fmt(&tk->tp, ptype);
1053 if (ret < 0)
1054 goto error;
1055
1056 ret = register_trace_kprobe(tk);
1057 if (ret) {
1058 trace_probe_log_set_index(1);
1059 if (ret == -EILSEQ)
1060 trace_probe_log_err(0, BAD_INSN_BNDRY);
1061 else if (ret == -ENOENT)
1062 trace_probe_log_err(0, BAD_PROBE_ADDR);
1063 else if (ret != -ENOMEM && ret != -EEXIST)
1064 trace_probe_log_err(0, FAIL_REG_PROBE);
1065 goto error;
1066 }
1067
1068out:
1069 traceprobe_finish_parse(&ctx);
1070 trace_probe_log_clear();
1071 kfree(new_argv);
1072 kfree(symbol);
1073 kfree(dbuf);
1074 return ret;
1075
1076parse_error:
1077 ret = -EINVAL;
1078error:
1079 free_trace_kprobe(tk);
1080 goto out;
1081}
1082
1083static int trace_kprobe_create(const char *raw_command)
1084{
1085 return trace_probe_create(raw_command, __trace_kprobe_create);
1086}
1087
1088static int create_or_delete_trace_kprobe(const char *raw_command)
1089{
1090 int ret;
1091
1092 if (raw_command[0] == '-')
1093 return dyn_event_release(raw_command, &trace_kprobe_ops);
1094
1095 ret = trace_kprobe_create(raw_command);
1096 return ret == -ECANCELED ? -EINVAL : ret;
1097}
1098
1099static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1100{
1101 return create_or_delete_trace_kprobe(cmd->seq.buffer);
1102}
1103
1104/**
1105 * kprobe_event_cmd_init - Initialize a kprobe event command object
1106 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1107 * @buf: A pointer to the buffer used to build the command
1108 * @maxlen: The length of the buffer passed in @buf
1109 *
1110 * Initialize a synthetic event command object. Use this before
1111 * calling any of the other kprobe_event functions.
1112 */
1113void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1114{
1115 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1116 trace_kprobe_run_command);
1117}
1118EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1119
1120/**
1121 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1122 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1123 * @kretprobe: Is this a return probe?
1124 * @name: The name of the kprobe event
1125 * @loc: The location of the kprobe event
1126 * @...: Variable number of arg (pairs), one pair for each field
1127 *
1128 * NOTE: Users normally won't want to call this function directly, but
1129 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1130 * adds a NULL to the end of the arg list. If this function is used
1131 * directly, make sure the last arg in the variable arg list is NULL.
1132 *
1133 * Generate a kprobe event command to be executed by
1134 * kprobe_event_gen_cmd_end(). This function can be used to generate the
1135 * complete command or only the first part of it; in the latter case,
1136 * kprobe_event_add_fields() can be used to add more fields following this.
1137 *
1138 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1139 * returns -EINVAL if @loc == NULL.
1140 *
1141 * Return: 0 if successful, error otherwise.
1142 */
1143int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1144 const char *name, const char *loc, ...)
1145{
1146 char buf[MAX_EVENT_NAME_LEN];
1147 struct dynevent_arg arg;
1148 va_list args;
1149 int ret;
1150
1151 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1152 return -EINVAL;
1153
1154 if (!loc)
1155 return -EINVAL;
1156
1157 if (kretprobe)
1158 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1159 else
1160 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1161
1162 ret = dynevent_str_add(cmd, buf);
1163 if (ret)
1164 return ret;
1165
1166 dynevent_arg_init(&arg, 0);
1167 arg.str = loc;
1168 ret = dynevent_arg_add(cmd, &arg, NULL);
1169 if (ret)
1170 return ret;
1171
1172 va_start(args, loc);
1173 for (;;) {
1174 const char *field;
1175
1176 field = va_arg(args, const char *);
1177 if (!field)
1178 break;
1179
1180 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1181 ret = -EINVAL;
1182 break;
1183 }
1184
1185 arg.str = field;
1186 ret = dynevent_arg_add(cmd, &arg, NULL);
1187 if (ret)
1188 break;
1189 }
1190 va_end(args);
1191
1192 return ret;
1193}
1194EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1195
1196/**
1197 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1198 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1199 * @...: Variable number of arg (pairs), one pair for each field
1200 *
1201 * NOTE: Users normally won't want to call this function directly, but
1202 * rather use the kprobe_event_add_fields() wrapper, which
1203 * automatically adds a NULL to the end of the arg list. If this
1204 * function is used directly, make sure the last arg in the variable
1205 * arg list is NULL.
1206 *
1207 * Add probe fields to an existing kprobe command using a variable
1208 * list of args. Fields are added in the same order they're listed.
1209 *
1210 * Return: 0 if successful, error otherwise.
1211 */
1212int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1213{
1214 struct dynevent_arg arg;
1215 va_list args;
1216 int ret = 0;
1217
1218 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1219 return -EINVAL;
1220
1221 dynevent_arg_init(&arg, 0);
1222
1223 va_start(args, cmd);
1224 for (;;) {
1225 const char *field;
1226
1227 field = va_arg(args, const char *);
1228 if (!field)
1229 break;
1230
1231 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1232 ret = -EINVAL;
1233 break;
1234 }
1235
1236 arg.str = field;
1237 ret = dynevent_arg_add(cmd, &arg, NULL);
1238 if (ret)
1239 break;
1240 }
1241 va_end(args);
1242
1243 return ret;
1244}
1245EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1246
1247/**
1248 * kprobe_event_delete - Delete a kprobe event
1249 * @name: The name of the kprobe event to delete
1250 *
1251 * Delete a kprobe event with the give @name from kernel code rather
1252 * than directly from the command line.
1253 *
1254 * Return: 0 if successful, error otherwise.
1255 */
1256int kprobe_event_delete(const char *name)
1257{
1258 char buf[MAX_EVENT_NAME_LEN];
1259
1260 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1261
1262 return create_or_delete_trace_kprobe(buf);
1263}
1264EXPORT_SYMBOL_GPL(kprobe_event_delete);
1265
1266static int trace_kprobe_release(struct dyn_event *ev)
1267{
1268 struct trace_kprobe *tk = to_trace_kprobe(ev);
1269 int ret = unregister_trace_kprobe(tk);
1270
1271 if (!ret)
1272 free_trace_kprobe(tk);
1273 return ret;
1274}
1275
1276static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1277{
1278 struct trace_kprobe *tk = to_trace_kprobe(ev);
1279 int i;
1280
1281 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1282 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1283 seq_printf(m, "%d", tk->rp.maxactive);
1284 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1285 trace_probe_name(&tk->tp));
1286
1287 if (!tk->symbol)
1288 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1289 else if (tk->rp.kp.offset)
1290 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1291 tk->rp.kp.offset);
1292 else
1293 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1294
1295 for (i = 0; i < tk->tp.nr_args; i++)
1296 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1297 seq_putc(m, '\n');
1298
1299 return 0;
1300}
1301
1302static int probes_seq_show(struct seq_file *m, void *v)
1303{
1304 struct dyn_event *ev = v;
1305
1306 if (!is_trace_kprobe(ev))
1307 return 0;
1308
1309 return trace_kprobe_show(m, ev);
1310}
1311
1312static const struct seq_operations probes_seq_op = {
1313 .start = dyn_event_seq_start,
1314 .next = dyn_event_seq_next,
1315 .stop = dyn_event_seq_stop,
1316 .show = probes_seq_show
1317};
1318
1319static int probes_open(struct inode *inode, struct file *file)
1320{
1321 int ret;
1322
1323 ret = security_locked_down(LOCKDOWN_TRACEFS);
1324 if (ret)
1325 return ret;
1326
1327 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1328 ret = dyn_events_release_all(&trace_kprobe_ops);
1329 if (ret < 0)
1330 return ret;
1331 }
1332
1333 return seq_open(file, &probes_seq_op);
1334}
1335
1336static ssize_t probes_write(struct file *file, const char __user *buffer,
1337 size_t count, loff_t *ppos)
1338{
1339 return trace_parse_run_command(file, buffer, count, ppos,
1340 create_or_delete_trace_kprobe);
1341}
1342
1343static const struct file_operations kprobe_events_ops = {
1344 .owner = THIS_MODULE,
1345 .open = probes_open,
1346 .read = seq_read,
1347 .llseek = seq_lseek,
1348 .release = seq_release,
1349 .write = probes_write,
1350};
1351
1352static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1353{
1354 return trace_kprobe_is_return(tk) ?
1355 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1356}
1357
1358/* Probes profiling interfaces */
1359static int probes_profile_seq_show(struct seq_file *m, void *v)
1360{
1361 struct dyn_event *ev = v;
1362 struct trace_kprobe *tk;
1363 unsigned long nmissed;
1364
1365 if (!is_trace_kprobe(ev))
1366 return 0;
1367
1368 tk = to_trace_kprobe(ev);
1369 nmissed = trace_kprobe_missed(tk);
1370 seq_printf(m, " %-44s %15lu %15lu\n",
1371 trace_probe_name(&tk->tp),
1372 trace_kprobe_nhit(tk),
1373 nmissed);
1374
1375 return 0;
1376}
1377
1378static const struct seq_operations profile_seq_op = {
1379 .start = dyn_event_seq_start,
1380 .next = dyn_event_seq_next,
1381 .stop = dyn_event_seq_stop,
1382 .show = probes_profile_seq_show
1383};
1384
1385static int profile_open(struct inode *inode, struct file *file)
1386{
1387 int ret;
1388
1389 ret = security_locked_down(LOCKDOWN_TRACEFS);
1390 if (ret)
1391 return ret;
1392
1393 return seq_open(file, &profile_seq_op);
1394}
1395
1396static const struct file_operations kprobe_profile_ops = {
1397 .owner = THIS_MODULE,
1398 .open = profile_open,
1399 .read = seq_read,
1400 .llseek = seq_lseek,
1401 .release = seq_release,
1402};
1403
1404/* Note that we don't verify it, since the code does not come from user space */
1405static int
1406process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1407 void *dest, void *base)
1408{
1409 struct pt_regs *regs = rec;
1410 unsigned long val;
1411 int ret;
1412
1413retry:
1414 /* 1st stage: get value from context */
1415 switch (code->op) {
1416 case FETCH_OP_REG:
1417 val = regs_get_register(regs, code->param);
1418 break;
1419 case FETCH_OP_STACK:
1420 val = regs_get_kernel_stack_nth(regs, code->param);
1421 break;
1422 case FETCH_OP_STACKP:
1423 val = kernel_stack_pointer(regs);
1424 break;
1425 case FETCH_OP_RETVAL:
1426 val = regs_return_value(regs);
1427 break;
1428#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1429 case FETCH_OP_ARG:
1430 val = regs_get_kernel_argument(regs, code->param);
1431 break;
1432 case FETCH_OP_EDATA:
1433 val = *(unsigned long *)((unsigned long)edata + code->offset);
1434 break;
1435#endif
1436 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1437 code++;
1438 goto retry;
1439 default:
1440 ret = process_common_fetch_insn(code, &val);
1441 if (ret < 0)
1442 return ret;
1443 }
1444 code++;
1445
1446 return process_fetch_insn_bottom(code, val, dest, base);
1447}
1448NOKPROBE_SYMBOL(process_fetch_insn)
1449
1450/* Kprobe handler */
1451static nokprobe_inline void
1452__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1453 struct trace_event_file *trace_file)
1454{
1455 struct kprobe_trace_entry_head *entry;
1456 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1457 struct trace_event_buffer fbuffer;
1458 int dsize;
1459
1460 WARN_ON(call != trace_file->event_call);
1461
1462 if (trace_trigger_soft_disabled(trace_file))
1463 return;
1464
1465 dsize = __get_data_size(&tk->tp, regs, NULL);
1466
1467 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1468 sizeof(*entry) + tk->tp.size + dsize);
1469 if (!entry)
1470 return;
1471
1472 fbuffer.regs = regs;
1473 entry->ip = (unsigned long)tk->rp.kp.addr;
1474 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1475
1476 trace_event_buffer_commit(&fbuffer);
1477}
1478
1479static void
1480kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1481{
1482 struct event_file_link *link;
1483
1484 trace_probe_for_each_link_rcu(link, &tk->tp)
1485 __kprobe_trace_func(tk, regs, link->file);
1486}
1487NOKPROBE_SYMBOL(kprobe_trace_func);
1488
1489/* Kretprobe handler */
1490
1491static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1492 struct pt_regs *regs)
1493{
1494 struct kretprobe *rp = get_kretprobe(ri);
1495 struct trace_kprobe *tk;
1496
1497 /*
1498 * There is a small chance that get_kretprobe(ri) returns NULL when
1499 * the kretprobe is unregister on another CPU between kretprobe's
1500 * trampoline_handler and this function.
1501 */
1502 if (unlikely(!rp))
1503 return -ENOENT;
1504
1505 tk = container_of(rp, struct trace_kprobe, rp);
1506
1507 /* store argument values into ri->data as entry data */
1508 if (tk->tp.entry_arg)
1509 store_trace_entry_data(ri->data, &tk->tp, regs);
1510
1511 return 0;
1512}
1513
1514
1515static nokprobe_inline void
1516__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1517 struct pt_regs *regs,
1518 struct trace_event_file *trace_file)
1519{
1520 struct kretprobe_trace_entry_head *entry;
1521 struct trace_event_buffer fbuffer;
1522 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1523 int dsize;
1524
1525 WARN_ON(call != trace_file->event_call);
1526
1527 if (trace_trigger_soft_disabled(trace_file))
1528 return;
1529
1530 dsize = __get_data_size(&tk->tp, regs, ri->data);
1531
1532 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1533 sizeof(*entry) + tk->tp.size + dsize);
1534 if (!entry)
1535 return;
1536
1537 fbuffer.regs = regs;
1538 entry->func = (unsigned long)tk->rp.kp.addr;
1539 entry->ret_ip = get_kretprobe_retaddr(ri);
1540 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1541
1542 trace_event_buffer_commit(&fbuffer);
1543}
1544
1545static void
1546kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1547 struct pt_regs *regs)
1548{
1549 struct event_file_link *link;
1550
1551 trace_probe_for_each_link_rcu(link, &tk->tp)
1552 __kretprobe_trace_func(tk, ri, regs, link->file);
1553}
1554NOKPROBE_SYMBOL(kretprobe_trace_func);
1555
1556/* Event entry printers */
1557static enum print_line_t
1558print_kprobe_event(struct trace_iterator *iter, int flags,
1559 struct trace_event *event)
1560{
1561 struct kprobe_trace_entry_head *field;
1562 struct trace_seq *s = &iter->seq;
1563 struct trace_probe *tp;
1564
1565 field = (struct kprobe_trace_entry_head *)iter->ent;
1566 tp = trace_probe_primary_from_call(
1567 container_of(event, struct trace_event_call, event));
1568 if (WARN_ON_ONCE(!tp))
1569 goto out;
1570
1571 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1572
1573 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1574 goto out;
1575
1576 trace_seq_putc(s, ')');
1577
1578 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1579 (u8 *)&field[1], field) < 0)
1580 goto out;
1581
1582 trace_seq_putc(s, '\n');
1583 out:
1584 return trace_handle_return(s);
1585}
1586
1587static enum print_line_t
1588print_kretprobe_event(struct trace_iterator *iter, int flags,
1589 struct trace_event *event)
1590{
1591 struct kretprobe_trace_entry_head *field;
1592 struct trace_seq *s = &iter->seq;
1593 struct trace_probe *tp;
1594
1595 field = (struct kretprobe_trace_entry_head *)iter->ent;
1596 tp = trace_probe_primary_from_call(
1597 container_of(event, struct trace_event_call, event));
1598 if (WARN_ON_ONCE(!tp))
1599 goto out;
1600
1601 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1602
1603 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1604 goto out;
1605
1606 trace_seq_puts(s, " <- ");
1607
1608 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1609 goto out;
1610
1611 trace_seq_putc(s, ')');
1612
1613 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1614 (u8 *)&field[1], field) < 0)
1615 goto out;
1616
1617 trace_seq_putc(s, '\n');
1618
1619 out:
1620 return trace_handle_return(s);
1621}
1622
1623
1624static int kprobe_event_define_fields(struct trace_event_call *event_call)
1625{
1626 int ret;
1627 struct kprobe_trace_entry_head field;
1628 struct trace_probe *tp;
1629
1630 tp = trace_probe_primary_from_call(event_call);
1631 if (WARN_ON_ONCE(!tp))
1632 return -ENOENT;
1633
1634 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1635
1636 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1637}
1638
1639static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1640{
1641 int ret;
1642 struct kretprobe_trace_entry_head field;
1643 struct trace_probe *tp;
1644
1645 tp = trace_probe_primary_from_call(event_call);
1646 if (WARN_ON_ONCE(!tp))
1647 return -ENOENT;
1648
1649 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1650 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1651
1652 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1653}
1654
1655#ifdef CONFIG_PERF_EVENTS
1656
1657/* Kprobe profile handler */
1658static int
1659kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1660{
1661 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1662 struct kprobe_trace_entry_head *entry;
1663 struct hlist_head *head;
1664 int size, __size, dsize;
1665 int rctx;
1666
1667 if (bpf_prog_array_valid(call)) {
1668 unsigned long orig_ip = instruction_pointer(regs);
1669 int ret;
1670
1671 ret = trace_call_bpf(call, regs);
1672
1673 /*
1674 * We need to check and see if we modified the pc of the
1675 * pt_regs, and if so return 1 so that we don't do the
1676 * single stepping.
1677 */
1678 if (orig_ip != instruction_pointer(regs))
1679 return 1;
1680 if (!ret)
1681 return 0;
1682 }
1683
1684 head = this_cpu_ptr(call->perf_events);
1685 if (hlist_empty(head))
1686 return 0;
1687
1688 dsize = __get_data_size(&tk->tp, regs, NULL);
1689 __size = sizeof(*entry) + tk->tp.size + dsize;
1690 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1691 size -= sizeof(u32);
1692
1693 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1694 if (!entry)
1695 return 0;
1696
1697 entry->ip = (unsigned long)tk->rp.kp.addr;
1698 memset(&entry[1], 0, dsize);
1699 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1700 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1701 head, NULL);
1702 return 0;
1703}
1704NOKPROBE_SYMBOL(kprobe_perf_func);
1705
1706/* Kretprobe profile handler */
1707static void
1708kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1709 struct pt_regs *regs)
1710{
1711 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1712 struct kretprobe_trace_entry_head *entry;
1713 struct hlist_head *head;
1714 int size, __size, dsize;
1715 int rctx;
1716
1717 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1718 return;
1719
1720 head = this_cpu_ptr(call->perf_events);
1721 if (hlist_empty(head))
1722 return;
1723
1724 dsize = __get_data_size(&tk->tp, regs, ri->data);
1725 __size = sizeof(*entry) + tk->tp.size + dsize;
1726 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1727 size -= sizeof(u32);
1728
1729 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1730 if (!entry)
1731 return;
1732
1733 entry->func = (unsigned long)tk->rp.kp.addr;
1734 entry->ret_ip = get_kretprobe_retaddr(ri);
1735 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1736 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1737 head, NULL);
1738}
1739NOKPROBE_SYMBOL(kretprobe_perf_func);
1740
1741int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1742 const char **symbol, u64 *probe_offset,
1743 u64 *probe_addr, unsigned long *missed,
1744 bool perf_type_tracepoint)
1745{
1746 const char *pevent = trace_event_name(event->tp_event);
1747 const char *group = event->tp_event->class->system;
1748 struct trace_kprobe *tk;
1749
1750 if (perf_type_tracepoint)
1751 tk = find_trace_kprobe(pevent, group);
1752 else
1753 tk = trace_kprobe_primary_from_call(event->tp_event);
1754 if (!tk)
1755 return -EINVAL;
1756
1757 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1758 : BPF_FD_TYPE_KPROBE;
1759 *probe_offset = tk->rp.kp.offset;
1760 *probe_addr = kallsyms_show_value(current_cred()) ?
1761 (unsigned long)tk->rp.kp.addr : 0;
1762 *symbol = tk->symbol;
1763 if (missed)
1764 *missed = trace_kprobe_missed(tk);
1765 return 0;
1766}
1767#endif /* CONFIG_PERF_EVENTS */
1768
1769/*
1770 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1771 *
1772 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1773 * lockless, but we can't race with this __init function.
1774 */
1775static int kprobe_register(struct trace_event_call *event,
1776 enum trace_reg type, void *data)
1777{
1778 struct trace_event_file *file = data;
1779
1780 switch (type) {
1781 case TRACE_REG_REGISTER:
1782 return enable_trace_kprobe(event, file);
1783 case TRACE_REG_UNREGISTER:
1784 return disable_trace_kprobe(event, file);
1785
1786#ifdef CONFIG_PERF_EVENTS
1787 case TRACE_REG_PERF_REGISTER:
1788 return enable_trace_kprobe(event, NULL);
1789 case TRACE_REG_PERF_UNREGISTER:
1790 return disable_trace_kprobe(event, NULL);
1791 case TRACE_REG_PERF_OPEN:
1792 case TRACE_REG_PERF_CLOSE:
1793 case TRACE_REG_PERF_ADD:
1794 case TRACE_REG_PERF_DEL:
1795 return 0;
1796#endif
1797 }
1798 return 0;
1799}
1800
1801static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1802{
1803 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1804 int ret = 0;
1805
1806 raw_cpu_inc(*tk->nhit);
1807
1808 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1809 kprobe_trace_func(tk, regs);
1810#ifdef CONFIG_PERF_EVENTS
1811 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1812 ret = kprobe_perf_func(tk, regs);
1813#endif
1814 return ret;
1815}
1816NOKPROBE_SYMBOL(kprobe_dispatcher);
1817
1818static int
1819kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1820{
1821 struct kretprobe *rp = get_kretprobe(ri);
1822 struct trace_kprobe *tk;
1823
1824 /*
1825 * There is a small chance that get_kretprobe(ri) returns NULL when
1826 * the kretprobe is unregister on another CPU between kretprobe's
1827 * trampoline_handler and this function.
1828 */
1829 if (unlikely(!rp))
1830 return 0;
1831
1832 tk = container_of(rp, struct trace_kprobe, rp);
1833 raw_cpu_inc(*tk->nhit);
1834
1835 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1836 kretprobe_trace_func(tk, ri, regs);
1837#ifdef CONFIG_PERF_EVENTS
1838 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1839 kretprobe_perf_func(tk, ri, regs);
1840#endif
1841 return 0; /* We don't tweak kernel, so just return 0 */
1842}
1843NOKPROBE_SYMBOL(kretprobe_dispatcher);
1844
1845static struct trace_event_functions kretprobe_funcs = {
1846 .trace = print_kretprobe_event
1847};
1848
1849static struct trace_event_functions kprobe_funcs = {
1850 .trace = print_kprobe_event
1851};
1852
1853static struct trace_event_fields kretprobe_fields_array[] = {
1854 { .type = TRACE_FUNCTION_TYPE,
1855 .define_fields = kretprobe_event_define_fields },
1856 {}
1857};
1858
1859static struct trace_event_fields kprobe_fields_array[] = {
1860 { .type = TRACE_FUNCTION_TYPE,
1861 .define_fields = kprobe_event_define_fields },
1862 {}
1863};
1864
1865static inline void init_trace_event_call(struct trace_kprobe *tk)
1866{
1867 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1868
1869 if (trace_kprobe_is_return(tk)) {
1870 call->event.funcs = &kretprobe_funcs;
1871 call->class->fields_array = kretprobe_fields_array;
1872 } else {
1873 call->event.funcs = &kprobe_funcs;
1874 call->class->fields_array = kprobe_fields_array;
1875 }
1876
1877 call->flags = TRACE_EVENT_FL_KPROBE;
1878 call->class->reg = kprobe_register;
1879}
1880
1881static int register_kprobe_event(struct trace_kprobe *tk)
1882{
1883 init_trace_event_call(tk);
1884
1885 return trace_probe_register_event_call(&tk->tp);
1886}
1887
1888static int unregister_kprobe_event(struct trace_kprobe *tk)
1889{
1890 return trace_probe_unregister_event_call(&tk->tp);
1891}
1892
1893#ifdef CONFIG_PERF_EVENTS
1894
1895/* create a trace_kprobe, but don't add it to global lists */
1896struct trace_event_call *
1897create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1898 bool is_return)
1899{
1900 enum probe_print_type ptype;
1901 struct trace_kprobe *tk;
1902 int ret;
1903 char *event;
1904
1905 if (func) {
1906 ret = validate_probe_symbol(func);
1907 if (ret)
1908 return ERR_PTR(ret);
1909 }
1910
1911 /*
1912 * local trace_kprobes are not added to dyn_event, so they are never
1913 * searched in find_trace_kprobe(). Therefore, there is no concern of
1914 * duplicated name here.
1915 */
1916 event = func ? func : "DUMMY_EVENT";
1917
1918 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1919 offs, 0 /* maxactive */, 0 /* nargs */,
1920 is_return);
1921
1922 if (IS_ERR(tk)) {
1923 pr_info("Failed to allocate trace_probe.(%d)\n",
1924 (int)PTR_ERR(tk));
1925 return ERR_CAST(tk);
1926 }
1927
1928 init_trace_event_call(tk);
1929
1930 ptype = trace_kprobe_is_return(tk) ?
1931 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1932 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1933 ret = -ENOMEM;
1934 goto error;
1935 }
1936
1937 ret = __register_trace_kprobe(tk);
1938 if (ret < 0)
1939 goto error;
1940
1941 return trace_probe_event_call(&tk->tp);
1942error:
1943 free_trace_kprobe(tk);
1944 return ERR_PTR(ret);
1945}
1946
1947void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1948{
1949 struct trace_kprobe *tk;
1950
1951 tk = trace_kprobe_primary_from_call(event_call);
1952 if (unlikely(!tk))
1953 return;
1954
1955 if (trace_probe_is_enabled(&tk->tp)) {
1956 WARN_ON(1);
1957 return;
1958 }
1959
1960 __unregister_trace_kprobe(tk);
1961
1962 free_trace_kprobe(tk);
1963}
1964#endif /* CONFIG_PERF_EVENTS */
1965
1966static __init void enable_boot_kprobe_events(void)
1967{
1968 struct trace_array *tr = top_trace_array();
1969 struct trace_event_file *file;
1970 struct trace_kprobe *tk;
1971 struct dyn_event *pos;
1972
1973 mutex_lock(&event_mutex);
1974 for_each_trace_kprobe(tk, pos) {
1975 list_for_each_entry(file, &tr->events, list)
1976 if (file->event_call == trace_probe_event_call(&tk->tp))
1977 trace_event_enable_disable(file, 1, 0);
1978 }
1979 mutex_unlock(&event_mutex);
1980}
1981
1982static __init void setup_boot_kprobe_events(void)
1983{
1984 char *p, *cmd = kprobe_boot_events_buf;
1985 int ret;
1986
1987 strreplace(kprobe_boot_events_buf, ',', ' ');
1988
1989 while (cmd && *cmd != '\0') {
1990 p = strchr(cmd, ';');
1991 if (p)
1992 *p++ = '\0';
1993
1994 ret = create_or_delete_trace_kprobe(cmd);
1995 if (ret)
1996 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1997
1998 cmd = p;
1999 }
2000
2001 enable_boot_kprobe_events();
2002}
2003
2004/*
2005 * Register dynevent at core_initcall. This allows kernel to setup kprobe
2006 * events in postcore_initcall without tracefs.
2007 */
2008static __init int init_kprobe_trace_early(void)
2009{
2010 int ret;
2011
2012 ret = dyn_event_register(&trace_kprobe_ops);
2013 if (ret)
2014 return ret;
2015
2016 if (trace_kprobe_register_module_notifier())
2017 return -EINVAL;
2018
2019 return 0;
2020}
2021core_initcall(init_kprobe_trace_early);
2022
2023/* Make a tracefs interface for controlling probe points */
2024static __init int init_kprobe_trace(void)
2025{
2026 int ret;
2027
2028 ret = tracing_init_dentry();
2029 if (ret)
2030 return 0;
2031
2032 /* Event list interface */
2033 trace_create_file("kprobe_events", TRACE_MODE_WRITE,
2034 NULL, NULL, &kprobe_events_ops);
2035
2036 /* Profile interface */
2037 trace_create_file("kprobe_profile", TRACE_MODE_READ,
2038 NULL, NULL, &kprobe_profile_ops);
2039
2040 setup_boot_kprobe_events();
2041
2042 return 0;
2043}
2044fs_initcall(init_kprobe_trace);
2045
2046
2047#ifdef CONFIG_FTRACE_STARTUP_TEST
2048static __init struct trace_event_file *
2049find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
2050{
2051 struct trace_event_file *file;
2052
2053 list_for_each_entry(file, &tr->events, list)
2054 if (file->event_call == trace_probe_event_call(&tk->tp))
2055 return file;
2056
2057 return NULL;
2058}
2059
2060/*
2061 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
2062 * stage, we can do this lockless.
2063 */
2064static __init int kprobe_trace_self_tests_init(void)
2065{
2066 int ret, warn = 0;
2067 int (*target)(int, int, int, int, int, int);
2068 struct trace_kprobe *tk;
2069 struct trace_event_file *file;
2070
2071 if (tracing_is_disabled())
2072 return -ENODEV;
2073
2074 if (tracing_selftest_disabled)
2075 return 0;
2076
2077 target = kprobe_trace_selftest_target;
2078
2079 pr_info("Testing kprobe tracing: ");
2080
2081 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2082 if (WARN_ONCE(ret, "error on probing function entry.")) {
2083 warn++;
2084 } else {
2085 /* Enable trace point */
2086 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2087 if (WARN_ONCE(tk == NULL, "error on probing function entry.")) {
2088 warn++;
2089 } else {
2090 file = find_trace_probe_file(tk, top_trace_array());
2091 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2092 warn++;
2093 } else
2094 enable_trace_kprobe(
2095 trace_probe_event_call(&tk->tp), file);
2096 }
2097 }
2098
2099 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2100 if (WARN_ONCE(ret, "error on probing function return.")) {
2101 warn++;
2102 } else {
2103 /* Enable trace point */
2104 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2105 if (WARN_ONCE(tk == NULL, "error on getting 2nd new probe.")) {
2106 warn++;
2107 } else {
2108 file = find_trace_probe_file(tk, top_trace_array());
2109 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2110 warn++;
2111 } else
2112 enable_trace_kprobe(
2113 trace_probe_event_call(&tk->tp), file);
2114 }
2115 }
2116
2117 if (warn)
2118 goto end;
2119
2120 ret = target(1, 2, 3, 4, 5, 6);
2121
2122 /*
2123 * Not expecting an error here, the check is only to prevent the
2124 * optimizer from removing the call to target() as otherwise there
2125 * are no side-effects and the call is never performed.
2126 */
2127 if (ret != 21)
2128 warn++;
2129
2130 /* Disable trace points before removing it */
2131 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2132 if (WARN_ONCE(tk == NULL, "error on getting test probe.")) {
2133 warn++;
2134 } else {
2135 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2136 "incorrect number of testprobe hits."))
2137 warn++;
2138
2139 file = find_trace_probe_file(tk, top_trace_array());
2140 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2141 warn++;
2142 } else
2143 disable_trace_kprobe(
2144 trace_probe_event_call(&tk->tp), file);
2145 }
2146
2147 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2148 if (WARN_ONCE(tk == NULL, "error on getting 2nd test probe.")) {
2149 warn++;
2150 } else {
2151 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2152 "incorrect number of testprobe2 hits."))
2153 warn++;
2154
2155 file = find_trace_probe_file(tk, top_trace_array());
2156 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2157 warn++;
2158 } else
2159 disable_trace_kprobe(
2160 trace_probe_event_call(&tk->tp), file);
2161 }
2162
2163 ret = create_or_delete_trace_kprobe("-:testprobe");
2164 if (WARN_ONCE(ret, "error on deleting a probe."))
2165 warn++;
2166
2167 ret = create_or_delete_trace_kprobe("-:testprobe2");
2168 if (WARN_ONCE(ret, "error on deleting a probe."))
2169 warn++;
2170
2171
2172end:
2173 /*
2174 * Wait for the optimizer work to finish. Otherwise it might fiddle
2175 * with probes in already freed __init text.
2176 */
2177 wait_for_kprobe_optimizer();
2178 if (warn)
2179 pr_cont("NG: Some tests are failed. Please check them.\n");
2180 else
2181 pr_cont("OK\n");
2182 return 0;
2183}
2184
2185late_initcall(kprobe_trace_self_tests_init);
2186
2187#endif