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/cleanup.h>
12#include <linux/error-injection.h>
13#include <linux/module.h>
14#include <linux/rculist.h>
15#include <linux/security.h>
16#include <linux/uaccess.h>
17
18#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
19
20#include "trace_dynevent.h"
21#include "trace_kprobe_selftest.h"
22#include "trace_probe.h"
23#include "trace_probe_kernel.h"
24#include "trace_probe_tmpl.h"
25
26#define KPROBE_EVENT_SYSTEM "kprobes"
27#define KRETPROBE_MAXACTIVE_MAX 4096
28
29/* Kprobe early definition from command line */
30static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
31
32static int __init set_kprobe_boot_events(char *str)
33{
34 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
35 disable_tracing_selftest(reason: "running kprobe events");
36
37 return 1;
38}
39__setup("kprobe_event=", set_kprobe_boot_events);
40
41static int trace_kprobe_create(const char *raw_command);
42static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
43static int trace_kprobe_release(struct dyn_event *ev);
44static bool trace_kprobe_is_busy(struct dyn_event *ev);
45static bool trace_kprobe_match(const char *system, const char *event,
46 int argc, const char **argv, struct dyn_event *ev);
47
48static struct dyn_event_operations trace_kprobe_ops = {
49 .create = trace_kprobe_create,
50 .show = trace_kprobe_show,
51 .is_busy = trace_kprobe_is_busy,
52 .free = trace_kprobe_release,
53 .match = trace_kprobe_match,
54};
55
56/*
57 * Kprobe event core functions
58 */
59struct trace_kprobe {
60 struct dyn_event devent;
61 struct kretprobe rp; /* Use rp.kp for kprobe use */
62 unsigned long __percpu *nhit;
63 const char *symbol; /* symbol name */
64 struct trace_probe tp;
65};
66
67static bool is_trace_kprobe(struct dyn_event *ev)
68{
69 return ev->ops == &trace_kprobe_ops;
70}
71
72static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
73{
74 return container_of(ev, struct trace_kprobe, devent);
75}
76
77/**
78 * for_each_trace_kprobe - iterate over the trace_kprobe list
79 * @pos: the struct trace_kprobe * for each entry
80 * @dpos: the struct dyn_event * to use as a loop cursor
81 */
82#define for_each_trace_kprobe(pos, dpos) \
83 for_each_dyn_event(dpos) \
84 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
85
86static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
87{
88 return tk->rp.handler != NULL;
89}
90
91static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
92{
93 return tk->symbol ? tk->symbol : "unknown";
94}
95
96static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
97{
98 return tk->rp.kp.offset;
99}
100
101static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
102{
103 return kprobe_gone(p: &tk->rp.kp);
104}
105
106static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
107 struct module *mod)
108{
109 int len = strlen(module_name(mod));
110 const char *name = trace_kprobe_symbol(tk);
111
112 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
113}
114
115#ifdef CONFIG_MODULES
116static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
117{
118 char *p;
119 bool ret;
120
121 if (!tk->symbol)
122 return false;
123 p = strchr(tk->symbol, ':');
124 if (!p)
125 return true;
126 *p = '\0';
127 scoped_guard(rcu)
128 ret = !!find_module(name: tk->symbol);
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(tp: &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, size: sizeof(buf), fmt: "0x%p", tk->rp.kp.addr);
157 else if (tk->rp.kp.offset)
158 snprintf(buf, size: sizeof(buf), fmt: "%s+%u",
159 trace_kprobe_symbol(tk), tk->rp.kp.offset);
160 else
161 snprintf(buf, size: sizeof(buf), fmt: "%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(tp: &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(tp: &tk->tp), event) == 0) &&
176 (!system || strcmp(trace_probe_group_name(tp: &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(head: &tk->rp.kp.list) &&
194 hlist_unhashed(h: &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(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(addr: tk->rp.kp.addr,
231 sym: tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
232 offset: 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(addr: 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(tp: &tk->tp);
254 kfree(objp: tk->symbol);
255 free_percpu(pdata: tk->nhit);
256 kfree(objp: tk);
257 }
258}
259
260DEFINE_FREE(free_trace_kprobe, struct trace_kprobe *,
261 if (!IS_ERR_OR_NULL(_T)) free_trace_kprobe(_T))
262
263/*
264 * Allocate new trace_probe and initialize it (including kprobes).
265 */
266static struct trace_kprobe *alloc_trace_kprobe(const char *group,
267 const char *event,
268 void *addr,
269 const char *symbol,
270 unsigned long offs,
271 int maxactive,
272 int nargs, bool is_return)
273{
274 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL;
275 int ret = -ENOMEM;
276
277 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
278 if (!tk)
279 return ERR_PTR(error: ret);
280
281 tk->nhit = alloc_percpu(unsigned long);
282 if (!tk->nhit)
283 return ERR_PTR(error: ret);
284
285 if (symbol) {
286 tk->symbol = kstrdup(s: symbol, GFP_KERNEL);
287 if (!tk->symbol)
288 return ERR_PTR(error: ret);
289 tk->rp.kp.symbol_name = tk->symbol;
290 tk->rp.kp.offset = offs;
291 } else
292 tk->rp.kp.addr = addr;
293
294 if (is_return)
295 tk->rp.handler = kretprobe_dispatcher;
296 else
297 tk->rp.kp.pre_handler = kprobe_dispatcher;
298
299 tk->rp.maxactive = maxactive;
300 INIT_HLIST_NODE(h: &tk->rp.kp.hlist);
301 INIT_LIST_HEAD(list: &tk->rp.kp.list);
302
303 ret = trace_probe_init(tp: &tk->tp, event, group, alloc_filter: false, nargs);
304 if (ret < 0)
305 return ERR_PTR(error: ret);
306
307 dyn_event_init(ev: &tk->devent, ops: &trace_kprobe_ops);
308 return_ptr(tk);
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(tp: &tk->tp), event) == 0 &&
319 strcmp(trace_probe_group_name(tp: &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(rp: &tk->rp);
331 else
332 ret = enable_kprobe(kp: &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(rp: &tk->rp);
347 else
348 disable_kprobe(kp: &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(what: 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(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(tp: &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(rp: &tk->rp);
516 else
517 ret = register_kprobe(p: &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(rp: &tk->rp);
528 else
529 unregister_kprobe(p: &tk->rp.kp);
530 /* Cleanup kprobe for reuse and mark it unregistered */
531 INIT_HLIST_NODE(h: &tk->rp.kp.hlist);
532 INIT_LIST_HEAD(list: &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(tp: &tk->tp))
543 goto unreg;
544
545 /* Enabled event can not be unregistered */
546 if (trace_probe_is_enabled(tp: &tk->tp))
547 return -EBUSY;
548
549 /* If there's a reference to the dynamic event */
550 if (trace_event_dyn_busy(call: trace_probe_event_call(tp: &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(ev: &tk->devent);
560 trace_probe_unlink(tp: &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(tk: orig),
573 trace_kprobe_symbol(tk: comp)) ||
574 trace_kprobe_offset(tk: orig) != trace_kprobe_offset(tk: 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(a: &tk->tp, b: &to->tp);
599 if (ret) {
600 /* Note that argument starts index = 2 */
601 trace_probe_log_set_index(index: ret + 1);
602 trace_probe_log_err(0, DIFF_ARG_TYPE);
603 return -EEXIST;
604 }
605 if (trace_kprobe_has_same_kprobe(orig: to, comp: tk)) {
606 trace_probe_log_set_index(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(tp: &tk->tp, to: &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(tp: &tk->tp);
625 else
626 dyn_event_add(ev: &tk->devent, call: trace_probe_event_call(tp: &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 guard(mutex)(T: &event_mutex);
638
639 old_tk = find_trace_kprobe(event: trace_probe_name(tp: &tk->tp),
640 group: trace_probe_group_name(tp: &tk->tp));
641 if (old_tk) {
642 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(tk: old_tk)) {
643 trace_probe_log_set_index(index: 0);
644 trace_probe_log_err(0, DIFF_PROBE_TYPE);
645 return -EEXIST;
646 }
647 return append_trace_kprobe(tk, to: old_tk);
648 }
649
650 /* Register new event */
651 ret = register_kprobe_event(tk);
652 if (ret) {
653 if (ret == -EEXIST) {
654 trace_probe_log_set_index(index: 0);
655 trace_probe_log_err(0, EVENT_EXIST);
656 } else
657 pr_warn("Failed to register probe event(%d)\n", ret);
658 return ret;
659 }
660
661 /* Register k*probe */
662 ret = __register_trace_kprobe(tk);
663 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
664 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
665 ret = 0;
666 }
667
668 if (ret < 0)
669 unregister_kprobe_event(tk);
670 else
671 dyn_event_add(ev: &tk->devent, call: trace_probe_event_call(tp: &tk->tp));
672
673 return ret;
674}
675
676#ifdef CONFIG_MODULES
677static int validate_module_probe_symbol(const char *modname, const char *symbol);
678
679static int register_module_trace_kprobe(struct module *mod, struct trace_kprobe *tk)
680{
681 const char *p;
682 int ret = 0;
683
684 p = strchr(trace_kprobe_symbol(tk), ':');
685 if (p)
686 ret = validate_module_probe_symbol(module_name(mod), symbol: p + 1);
687 if (!ret)
688 ret = __register_trace_kprobe(tk);
689 return ret;
690}
691
692/* Module notifier call back, checking event on the module */
693static int trace_kprobe_module_callback(struct notifier_block *nb,
694 unsigned long val, void *data)
695{
696 struct module *mod = data;
697 struct dyn_event *pos;
698 struct trace_kprobe *tk;
699 int ret;
700
701 if (val != MODULE_STATE_COMING)
702 return NOTIFY_DONE;
703
704 /* Update probes on coming module */
705 guard(mutex)(T: &event_mutex);
706 for_each_trace_kprobe(tk, pos) {
707 if (trace_kprobe_within_module(tk, mod)) {
708 /* Don't need to check busy - this should have gone. */
709 __unregister_trace_kprobe(tk);
710 ret = register_module_trace_kprobe(mod, tk);
711 if (ret)
712 pr_warn("Failed to re-register probe %s on %s: %d\n",
713 trace_probe_name(&tk->tp),
714 module_name(mod), ret);
715 }
716 }
717
718 return NOTIFY_DONE;
719}
720
721static struct notifier_block trace_kprobe_module_nb = {
722 .notifier_call = trace_kprobe_module_callback,
723 .priority = 2 /* Invoked after kprobe and jump_label module callback */
724};
725static int trace_kprobe_register_module_notifier(void)
726{
727 return register_module_notifier(nb: &trace_kprobe_module_nb);
728}
729#else
730static int trace_kprobe_register_module_notifier(void)
731{
732 return 0;
733}
734#endif /* CONFIG_MODULES */
735
736static int count_symbols(void *data, unsigned long unused)
737{
738 unsigned int *count = data;
739
740 (*count)++;
741
742 return 0;
743}
744
745struct sym_count_ctx {
746 unsigned int count;
747 const char *name;
748};
749
750static int count_mod_symbols(void *data, const char *name, unsigned long unused)
751{
752 struct sym_count_ctx *ctx = data;
753
754 if (strcmp(name, ctx->name) == 0)
755 ctx->count++;
756
757 return 0;
758}
759
760static unsigned int number_of_same_symbols(const char *mod, const char *func_name)
761{
762 struct sym_count_ctx ctx = { .count = 0, .name = func_name };
763
764 if (!mod)
765 kallsyms_on_each_match_symbol(fn: count_symbols, name: func_name, data: &ctx.count);
766
767 module_kallsyms_on_each_symbol(modname: mod, fn: count_mod_symbols, data: &ctx);
768
769 return ctx.count;
770}
771
772static int validate_module_probe_symbol(const char *modname, const char *symbol)
773{
774 unsigned int count = number_of_same_symbols(mod: modname, func_name: symbol);
775
776 if (count > 1) {
777 /*
778 * Users should use ADDR to remove the ambiguity of
779 * using KSYM only.
780 */
781 return -EADDRNOTAVAIL;
782 } else if (count == 0) {
783 /*
784 * We can return ENOENT earlier than when register the
785 * kprobe.
786 */
787 return -ENOENT;
788 }
789 return 0;
790}
791
792#ifdef CONFIG_MODULES
793/* Return NULL if the module is not loaded or under unloading. */
794static struct module *try_module_get_by_name(const char *name)
795{
796 struct module *mod;
797
798 guard(rcu)();
799 mod = find_module(name);
800 if (mod && !try_module_get(module: mod))
801 mod = NULL;
802 return mod;
803}
804#else
805#define try_module_get_by_name(name) (NULL)
806#endif
807
808static int validate_probe_symbol(char *symbol)
809{
810 struct module *mod = NULL;
811 char *modname = NULL, *p;
812 int ret = 0;
813
814 p = strchr(symbol, ':');
815 if (p) {
816 modname = symbol;
817 symbol = p + 1;
818 *p = '\0';
819 mod = try_module_get_by_name(name: modname);
820 if (!mod)
821 goto out;
822 }
823
824 ret = validate_module_probe_symbol(modname, symbol);
825out:
826 if (p)
827 *p = ':';
828 if (mod)
829 module_put(module: mod);
830 return ret;
831}
832
833static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
834 struct pt_regs *regs);
835
836static int trace_kprobe_create_internal(int argc, const char *argv[],
837 struct traceprobe_parse_context *ctx)
838{
839 /*
840 * Argument syntax:
841 * - Add kprobe:
842 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
843 * - Add kretprobe:
844 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
845 * Or
846 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
847 *
848 * Fetch args:
849 * $retval : fetch return value
850 * $stack : fetch stack address
851 * $stackN : fetch Nth of stack (N:0-)
852 * $comm : fetch current task comm
853 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
854 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
855 * %REG : fetch register REG
856 * Dereferencing memory fetch:
857 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
858 * Alias name of args:
859 * NAME=FETCHARG : set NAME as alias of FETCHARG.
860 * Type of args:
861 * FETCHARG:TYPE : use TYPE instead of unsigned long.
862 */
863 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL;
864 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
865 const char **new_argv __free(kfree) = NULL;
866 int i, len, new_argc = 0, ret = 0;
867 char *symbol __free(kfree) = NULL;
868 char *ebuf __free(kfree) = NULL;
869 char *gbuf __free(kfree) = NULL;
870 char *abuf __free(kfree) = NULL;
871 char *dbuf __free(kfree) = NULL;
872 enum probe_print_type ptype;
873 bool is_return = false;
874 int maxactive = 0;
875 void *addr = NULL;
876 char *tmp = NULL;
877 long offset = 0;
878
879 switch (argv[0][0]) {
880 case 'r':
881 is_return = true;
882 break;
883 case 'p':
884 break;
885 default:
886 return -ECANCELED;
887 }
888 if (argc < 2)
889 return -ECANCELED;
890
891 event = strchr(&argv[0][1], ':');
892 if (event)
893 event++;
894
895 if (isdigit(c: argv[0][1])) {
896 char *buf __free(kfree) = NULL;
897
898 if (!is_return) {
899 trace_probe_log_err(1, BAD_MAXACT_TYPE);
900 return -EINVAL;
901 }
902 if (event)
903 len = event - &argv[0][1] - 1;
904 else
905 len = strlen(&argv[0][1]);
906 if (len > MAX_EVENT_NAME_LEN - 1) {
907 trace_probe_log_err(1, BAD_MAXACT);
908 return -EINVAL;
909 }
910 buf = kmemdup(&argv[0][1], len + 1, GFP_KERNEL);
911 if (!buf)
912 return -ENOMEM;
913 buf[len] = '\0';
914 ret = kstrtouint(s: buf, base: 0, res: &maxactive);
915 if (ret || !maxactive) {
916 trace_probe_log_err(1, BAD_MAXACT);
917 return -EINVAL;
918 }
919 /* kretprobes instances are iterated over via a list. The
920 * maximum should stay reasonable.
921 */
922 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
923 trace_probe_log_err(1, MAXACT_TOO_BIG);
924 return -EINVAL;
925 }
926 }
927
928 /* try to parse an address. if that fails, try to read the
929 * input as a symbol. */
930 if (kstrtoul(s: argv[1], base: 0, res: (unsigned long *)&addr)) {
931 trace_probe_log_set_index(index: 1);
932 /* Check whether uprobe event specified */
933 if (strchr(argv[1], '/') && strchr(argv[1], ':'))
934 return -ECANCELED;
935
936 /* a symbol specified */
937 symbol = kstrdup(s: argv[1], GFP_KERNEL);
938 if (!symbol)
939 return -ENOMEM;
940
941 tmp = strchr(symbol, '%');
942 if (tmp) {
943 if (!strcmp(tmp, "%return")) {
944 *tmp = '\0';
945 is_return = true;
946 } else {
947 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
948 return -EINVAL;
949 }
950 }
951
952 /* TODO: support .init module functions */
953 ret = traceprobe_split_symbol_offset(symbol, offset: &offset);
954 if (ret || offset < 0 || offset > UINT_MAX) {
955 trace_probe_log_err(0, BAD_PROBE_ADDR);
956 return -EINVAL;
957 }
958 ret = validate_probe_symbol(symbol);
959 if (ret) {
960 if (ret == -EADDRNOTAVAIL)
961 trace_probe_log_err(0, NON_UNIQ_SYMBOL);
962 else
963 trace_probe_log_err(0, BAD_PROBE_ADDR);
964 return -EINVAL;
965 }
966 if (is_return)
967 ctx->flags |= TPARG_FL_RETURN;
968 ret = kprobe_on_func_entry(NULL, sym: symbol, offset);
969 if (ret == 0 && !is_return)
970 ctx->flags |= TPARG_FL_FENTRY;
971 /* Defer the ENOENT case until register kprobe */
972 if (ret == -EINVAL && is_return) {
973 trace_probe_log_err(0, BAD_RETPROBE);
974 return -EINVAL;
975 }
976 }
977
978 trace_probe_log_set_index(index: 0);
979 if (event) {
980 gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
981 if (!gbuf)
982 return -ENOMEM;
983 ret = traceprobe_parse_event_name(pevent: &event, pgroup: &group, buf: gbuf,
984 offset: event - argv[0]);
985 if (ret)
986 return ret;
987 }
988
989 if (!event) {
990 /* Make a new event name */
991 ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
992 if (!ebuf)
993 return -ENOMEM;
994 if (symbol)
995 snprintf(buf: ebuf, MAX_EVENT_NAME_LEN, fmt: "%c_%s_%ld",
996 is_return ? 'r' : 'p', symbol, offset);
997 else
998 snprintf(buf: ebuf, MAX_EVENT_NAME_LEN, fmt: "%c_0x%p",
999 is_return ? 'r' : 'p', addr);
1000 sanitize_event_name(name: ebuf);
1001 event = ebuf;
1002 }
1003
1004 abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL);
1005 if (!abuf)
1006 return -ENOMEM;
1007 argc -= 2; argv += 2;
1008 ctx->funcname = symbol;
1009 new_argv = traceprobe_expand_meta_args(argc, argv, new_argc: &new_argc,
1010 buf: abuf, MAX_BTF_ARGS_LEN, ctx);
1011 if (IS_ERR(ptr: new_argv)) {
1012 ret = PTR_ERR(ptr: new_argv);
1013 new_argv = NULL;
1014 return ret;
1015 }
1016 if (new_argv) {
1017 argc = new_argc;
1018 argv = new_argv;
1019 }
1020 if (argc > MAX_TRACE_ARGS) {
1021 trace_probe_log_set_index(index: 2);
1022 trace_probe_log_err(0, TOO_MANY_ARGS);
1023 return -E2BIG;
1024 }
1025
1026 ret = traceprobe_expand_dentry_args(argc, argv, buf: &dbuf);
1027 if (ret)
1028 return ret;
1029
1030 /* setup a probe */
1031 tk = alloc_trace_kprobe(group, event, addr, symbol, offs: offset, maxactive,
1032 nargs: argc, is_return);
1033 if (IS_ERR(ptr: tk)) {
1034 ret = PTR_ERR(ptr: tk);
1035 /* This must return -ENOMEM, else there is a bug */
1036 WARN_ON_ONCE(ret != -ENOMEM);
1037 return ret; /* We know tk is not allocated */
1038 }
1039
1040 /* parse arguments */
1041 for (i = 0; i < argc; i++) {
1042 trace_probe_log_set_index(index: i + 2);
1043 ctx->offset = 0;
1044 ret = traceprobe_parse_probe_arg(tp: &tk->tp, i, argv: argv[i], ctx);
1045 if (ret)
1046 return ret; /* This can be -ENOMEM */
1047 }
1048 /* entry handler for kretprobe */
1049 if (is_return && tk->tp.entry_arg) {
1050 tk->rp.entry_handler = trace_kprobe_entry_handler;
1051 tk->rp.data_size = traceprobe_get_entry_data_size(tp: &tk->tp);
1052 }
1053
1054 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1055 ret = traceprobe_set_print_fmt(tp: &tk->tp, ptype);
1056 if (ret < 0)
1057 return ret;
1058
1059 ret = register_trace_kprobe(tk);
1060 if (ret) {
1061 trace_probe_log_set_index(index: 1);
1062 if (ret == -EILSEQ)
1063 trace_probe_log_err(0, BAD_INSN_BNDRY);
1064 else if (ret == -ENOENT)
1065 trace_probe_log_err(0, BAD_PROBE_ADDR);
1066 else if (ret != -ENOMEM && ret != -EEXIST)
1067 trace_probe_log_err(0, FAIL_REG_PROBE);
1068 return ret;
1069 }
1070 /*
1071 * Here, 'tk' has been registered to the list successfully,
1072 * so we don't need to free it.
1073 */
1074 tk = NULL;
1075
1076 return 0;
1077}
1078
1079static int trace_kprobe_create_cb(int argc, const char *argv[])
1080{
1081 struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL;
1082 int ret;
1083
1084 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
1085 if (!ctx)
1086 return -ENOMEM;
1087 ctx->flags = TPARG_FL_KERNEL;
1088
1089 trace_probe_log_init(subsystem: "trace_kprobe", argc, argv);
1090
1091 ret = trace_kprobe_create_internal(argc, argv, ctx);
1092
1093 trace_probe_log_clear();
1094 return ret;
1095}
1096
1097static int trace_kprobe_create(const char *raw_command)
1098{
1099 return trace_probe_create(raw_command, createfn: trace_kprobe_create_cb);
1100}
1101
1102static int create_or_delete_trace_kprobe(const char *raw_command)
1103{
1104 int ret;
1105
1106 if (raw_command[0] == '-')
1107 return dyn_event_release(raw_command, type: &trace_kprobe_ops);
1108
1109 ret = dyn_event_create(raw_command, type: &trace_kprobe_ops);
1110 return ret == -ECANCELED ? -EINVAL : ret;
1111}
1112
1113static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1114{
1115 return create_or_delete_trace_kprobe(raw_command: cmd->seq.buffer);
1116}
1117
1118/**
1119 * kprobe_event_cmd_init - Initialize a kprobe event command object
1120 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1121 * @buf: A pointer to the buffer used to build the command
1122 * @maxlen: The length of the buffer passed in @buf
1123 *
1124 * Initialize a synthetic event command object. Use this before
1125 * calling any of the other kprobe_event functions.
1126 */
1127void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1128{
1129 dynevent_cmd_init(cmd, buf, maxlen, type: DYNEVENT_TYPE_KPROBE,
1130 run_command: trace_kprobe_run_command);
1131}
1132EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1133
1134/**
1135 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1136 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1137 * @kretprobe: Is this a return probe?
1138 * @name: The name of the kprobe event
1139 * @loc: The location of the kprobe event
1140 * @...: Variable number of arg (pairs), one pair for each field
1141 *
1142 * NOTE: Users normally won't want to call this function directly, but
1143 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1144 * adds a NULL to the end of the arg list. If this function is used
1145 * directly, make sure the last arg in the variable arg list is NULL.
1146 *
1147 * Generate a kprobe event command to be executed by
1148 * kprobe_event_gen_cmd_end(). This function can be used to generate the
1149 * complete command or only the first part of it; in the latter case,
1150 * kprobe_event_add_fields() can be used to add more fields following this.
1151 *
1152 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1153 * returns -EINVAL if @loc == NULL.
1154 *
1155 * Return: 0 if successful, error otherwise.
1156 */
1157int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1158 const char *name, const char *loc, ...)
1159{
1160 char buf[MAX_EVENT_NAME_LEN];
1161 struct dynevent_arg arg;
1162 va_list args;
1163 int ret;
1164
1165 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1166 return -EINVAL;
1167
1168 if (!loc)
1169 return -EINVAL;
1170
1171 if (kretprobe)
1172 snprintf(buf, MAX_EVENT_NAME_LEN, fmt: "r:kprobes/%s", name);
1173 else
1174 snprintf(buf, MAX_EVENT_NAME_LEN, fmt: "p:kprobes/%s", name);
1175
1176 ret = dynevent_str_add(cmd, str: buf);
1177 if (ret)
1178 return ret;
1179
1180 dynevent_arg_init(arg: &arg, separator: 0);
1181 arg.str = loc;
1182 ret = dynevent_arg_add(cmd, arg: &arg, NULL);
1183 if (ret)
1184 return ret;
1185
1186 va_start(args, loc);
1187 for (;;) {
1188 const char *field;
1189
1190 field = va_arg(args, const char *);
1191 if (!field)
1192 break;
1193
1194 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1195 ret = -EINVAL;
1196 break;
1197 }
1198
1199 arg.str = field;
1200 ret = dynevent_arg_add(cmd, arg: &arg, NULL);
1201 if (ret)
1202 break;
1203 }
1204 va_end(args);
1205
1206 return ret;
1207}
1208EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1209
1210/**
1211 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1212 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1213 * @...: Variable number of arg (pairs), one pair for each field
1214 *
1215 * NOTE: Users normally won't want to call this function directly, but
1216 * rather use the kprobe_event_add_fields() wrapper, which
1217 * automatically adds a NULL to the end of the arg list. If this
1218 * function is used directly, make sure the last arg in the variable
1219 * arg list is NULL.
1220 *
1221 * Add probe fields to an existing kprobe command using a variable
1222 * list of args. Fields are added in the same order they're listed.
1223 *
1224 * Return: 0 if successful, error otherwise.
1225 */
1226int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1227{
1228 struct dynevent_arg arg;
1229 va_list args;
1230 int ret = 0;
1231
1232 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1233 return -EINVAL;
1234
1235 dynevent_arg_init(arg: &arg, separator: 0);
1236
1237 va_start(args, cmd);
1238 for (;;) {
1239 const char *field;
1240
1241 field = va_arg(args, const char *);
1242 if (!field)
1243 break;
1244
1245 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1246 ret = -EINVAL;
1247 break;
1248 }
1249
1250 arg.str = field;
1251 ret = dynevent_arg_add(cmd, arg: &arg, NULL);
1252 if (ret)
1253 break;
1254 }
1255 va_end(args);
1256
1257 return ret;
1258}
1259EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1260
1261/**
1262 * kprobe_event_delete - Delete a kprobe event
1263 * @name: The name of the kprobe event to delete
1264 *
1265 * Delete a kprobe event with the give @name from kernel code rather
1266 * than directly from the command line.
1267 *
1268 * Return: 0 if successful, error otherwise.
1269 */
1270int kprobe_event_delete(const char *name)
1271{
1272 char buf[MAX_EVENT_NAME_LEN];
1273
1274 snprintf(buf, MAX_EVENT_NAME_LEN, fmt: "-:%s", name);
1275
1276 return create_or_delete_trace_kprobe(raw_command: buf);
1277}
1278EXPORT_SYMBOL_GPL(kprobe_event_delete);
1279
1280static int trace_kprobe_release(struct dyn_event *ev)
1281{
1282 struct trace_kprobe *tk = to_trace_kprobe(ev);
1283 int ret = unregister_trace_kprobe(tk);
1284
1285 if (!ret)
1286 free_trace_kprobe(tk);
1287 return ret;
1288}
1289
1290static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1291{
1292 struct trace_kprobe *tk = to_trace_kprobe(ev);
1293 int i;
1294
1295 seq_putc(m, c: trace_kprobe_is_return(tk) ? 'r' : 'p');
1296 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1297 seq_printf(m, fmt: "%d", tk->rp.maxactive);
1298 seq_printf(m, fmt: ":%s/%s", trace_probe_group_name(tp: &tk->tp),
1299 trace_probe_name(tp: &tk->tp));
1300
1301 if (!tk->symbol)
1302 seq_printf(m, fmt: " 0x%p", tk->rp.kp.addr);
1303 else if (tk->rp.kp.offset)
1304 seq_printf(m, fmt: " %s+%u", trace_kprobe_symbol(tk),
1305 tk->rp.kp.offset);
1306 else
1307 seq_printf(m, fmt: " %s", trace_kprobe_symbol(tk));
1308
1309 for (i = 0; i < tk->tp.nr_args; i++)
1310 seq_printf(m, fmt: " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1311 seq_putc(m, c: '\n');
1312
1313 return 0;
1314}
1315
1316static int probes_seq_show(struct seq_file *m, void *v)
1317{
1318 struct dyn_event *ev = v;
1319
1320 if (!is_trace_kprobe(ev))
1321 return 0;
1322
1323 return trace_kprobe_show(m, ev);
1324}
1325
1326static const struct seq_operations probes_seq_op = {
1327 .start = dyn_event_seq_start,
1328 .next = dyn_event_seq_next,
1329 .stop = dyn_event_seq_stop,
1330 .show = probes_seq_show
1331};
1332
1333static int probes_open(struct inode *inode, struct file *file)
1334{
1335 int ret;
1336
1337 ret = security_locked_down(what: LOCKDOWN_TRACEFS);
1338 if (ret)
1339 return ret;
1340
1341 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1342 ret = dyn_events_release_all(type: &trace_kprobe_ops);
1343 if (ret < 0)
1344 return ret;
1345 }
1346
1347 return seq_open(file, &probes_seq_op);
1348}
1349
1350static ssize_t probes_write(struct file *file, const char __user *buffer,
1351 size_t count, loff_t *ppos)
1352{
1353 return trace_parse_run_command(file, buffer, count, ppos,
1354 createfn: create_or_delete_trace_kprobe);
1355}
1356
1357static const struct file_operations kprobe_events_ops = {
1358 .owner = THIS_MODULE,
1359 .open = probes_open,
1360 .read = seq_read,
1361 .llseek = seq_lseek,
1362 .release = seq_release,
1363 .write = probes_write,
1364};
1365
1366static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1367{
1368 return trace_kprobe_is_return(tk) ?
1369 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1370}
1371
1372/* Probes profiling interfaces */
1373static int probes_profile_seq_show(struct seq_file *m, void *v)
1374{
1375 struct dyn_event *ev = v;
1376 struct trace_kprobe *tk;
1377 unsigned long nmissed;
1378
1379 if (!is_trace_kprobe(ev))
1380 return 0;
1381
1382 tk = to_trace_kprobe(ev);
1383 nmissed = trace_kprobe_missed(tk);
1384 seq_printf(m, fmt: " %-44s %15lu %15lu\n",
1385 trace_probe_name(tp: &tk->tp),
1386 trace_kprobe_nhit(tk),
1387 nmissed);
1388
1389 return 0;
1390}
1391
1392static const struct seq_operations profile_seq_op = {
1393 .start = dyn_event_seq_start,
1394 .next = dyn_event_seq_next,
1395 .stop = dyn_event_seq_stop,
1396 .show = probes_profile_seq_show
1397};
1398
1399static int profile_open(struct inode *inode, struct file *file)
1400{
1401 int ret;
1402
1403 ret = security_locked_down(what: LOCKDOWN_TRACEFS);
1404 if (ret)
1405 return ret;
1406
1407 return seq_open(file, &profile_seq_op);
1408}
1409
1410static const struct file_operations kprobe_profile_ops = {
1411 .owner = THIS_MODULE,
1412 .open = profile_open,
1413 .read = seq_read,
1414 .llseek = seq_lseek,
1415 .release = seq_release,
1416};
1417
1418/* Note that we don't verify it, since the code does not come from user space */
1419static int
1420process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1421 void *dest, void *base)
1422{
1423 struct pt_regs *regs = rec;
1424 unsigned long val;
1425 int ret;
1426
1427retry:
1428 /* 1st stage: get value from context */
1429 switch (code->op) {
1430 case FETCH_OP_REG:
1431 val = regs_get_register(regs, offset: code->param);
1432 break;
1433 case FETCH_OP_STACK:
1434 val = regs_get_kernel_stack_nth(regs, n: code->param);
1435 break;
1436 case FETCH_OP_STACKP:
1437 val = kernel_stack_pointer(regs);
1438 break;
1439 case FETCH_OP_RETVAL:
1440 val = regs_return_value(regs);
1441 break;
1442#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1443 case FETCH_OP_ARG:
1444 val = regs_get_kernel_argument(regs, n: code->param);
1445 break;
1446 case FETCH_OP_EDATA:
1447 val = *(unsigned long *)((unsigned long)edata + code->offset);
1448 break;
1449#endif
1450 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1451 code++;
1452 goto retry;
1453 default:
1454 ret = process_common_fetch_insn(code, val: &val);
1455 if (ret < 0)
1456 return ret;
1457 }
1458 code++;
1459
1460 return process_fetch_insn_bottom(code, val, dest, base);
1461}
1462NOKPROBE_SYMBOL(process_fetch_insn)
1463
1464/* Kprobe handler */
1465static nokprobe_inline void
1466__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1467 struct trace_event_file *trace_file)
1468{
1469 struct kprobe_trace_entry_head *entry;
1470 struct trace_event_call *call = trace_probe_event_call(tp: &tk->tp);
1471 struct trace_event_buffer fbuffer;
1472 int dsize;
1473
1474 WARN_ON(call != trace_file->event_call);
1475
1476 if (trace_trigger_soft_disabled(file: trace_file))
1477 return;
1478
1479 dsize = __get_data_size(tp: &tk->tp, regs, NULL);
1480
1481 entry = trace_event_buffer_reserve(fbuffer: &fbuffer, trace_file,
1482 len: sizeof(*entry) + tk->tp.size + dsize);
1483 if (!entry)
1484 return;
1485
1486 fbuffer.regs = regs;
1487 entry->ip = (unsigned long)tk->rp.kp.addr;
1488 store_trace_args(data: &entry[1], tp: &tk->tp, rec: regs, NULL, header_size: sizeof(*entry), maxlen: dsize);
1489
1490 trace_event_buffer_commit(fbuffer: &fbuffer);
1491}
1492
1493static void
1494kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1495{
1496 struct event_file_link *link;
1497
1498 trace_probe_for_each_link_rcu(link, &tk->tp)
1499 __kprobe_trace_func(tk, regs, trace_file: link->file);
1500}
1501NOKPROBE_SYMBOL(kprobe_trace_func);
1502
1503/* Kretprobe handler */
1504
1505static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1506 struct pt_regs *regs)
1507{
1508 struct kretprobe *rp = get_kretprobe(ri);
1509 struct trace_kprobe *tk;
1510
1511 /*
1512 * There is a small chance that get_kretprobe(ri) returns NULL when
1513 * the kretprobe is unregister on another CPU between kretprobe's
1514 * trampoline_handler and this function.
1515 */
1516 if (unlikely(!rp))
1517 return -ENOENT;
1518
1519 tk = container_of(rp, struct trace_kprobe, rp);
1520
1521 /* store argument values into ri->data as entry data */
1522 if (tk->tp.entry_arg)
1523 store_trace_entry_data(edata: ri->data, tp: &tk->tp, regs);
1524
1525 return 0;
1526}
1527
1528
1529static nokprobe_inline void
1530__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1531 struct pt_regs *regs,
1532 struct trace_event_file *trace_file)
1533{
1534 struct kretprobe_trace_entry_head *entry;
1535 struct trace_event_buffer fbuffer;
1536 struct trace_event_call *call = trace_probe_event_call(tp: &tk->tp);
1537 int dsize;
1538
1539 WARN_ON(call != trace_file->event_call);
1540
1541 if (trace_trigger_soft_disabled(file: trace_file))
1542 return;
1543
1544 dsize = __get_data_size(tp: &tk->tp, regs, edata: ri->data);
1545
1546 entry = trace_event_buffer_reserve(fbuffer: &fbuffer, trace_file,
1547 len: sizeof(*entry) + tk->tp.size + dsize);
1548 if (!entry)
1549 return;
1550
1551 fbuffer.regs = regs;
1552 entry->func = (unsigned long)tk->rp.kp.addr;
1553 entry->ret_ip = get_kretprobe_retaddr(ri);
1554 store_trace_args(data: &entry[1], tp: &tk->tp, rec: regs, edata: ri->data, header_size: sizeof(*entry), maxlen: dsize);
1555
1556 trace_event_buffer_commit(fbuffer: &fbuffer);
1557}
1558
1559static void
1560kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1561 struct pt_regs *regs)
1562{
1563 struct event_file_link *link;
1564
1565 trace_probe_for_each_link_rcu(link, &tk->tp)
1566 __kretprobe_trace_func(tk, ri, regs, trace_file: link->file);
1567}
1568NOKPROBE_SYMBOL(kretprobe_trace_func);
1569
1570/* Event entry printers */
1571static enum print_line_t
1572print_kprobe_event(struct trace_iterator *iter, int flags,
1573 struct trace_event *event)
1574{
1575 struct kprobe_trace_entry_head *field;
1576 struct trace_seq *s = &iter->seq;
1577 struct trace_probe *tp;
1578
1579 field = (struct kprobe_trace_entry_head *)iter->ent;
1580 tp = trace_probe_primary_from_call(
1581 container_of(event, struct trace_event_call, event));
1582 if (WARN_ON_ONCE(!tp))
1583 goto out;
1584
1585 trace_seq_printf(s, fmt: "%s: (", trace_probe_name(tp));
1586
1587 if (!seq_print_ip_sym(s, ip: field->ip, sym_flags: flags | TRACE_ITER_SYM_OFFSET))
1588 goto out;
1589
1590 trace_seq_putc(s, c: ')');
1591
1592 if (trace_probe_print_args(s, args: tp->args, nr_args: tp->nr_args,
1593 data: (u8 *)&field[1], field) < 0)
1594 goto out;
1595
1596 trace_seq_putc(s, c: '\n');
1597 out:
1598 return trace_handle_return(s);
1599}
1600
1601static enum print_line_t
1602print_kretprobe_event(struct trace_iterator *iter, int flags,
1603 struct trace_event *event)
1604{
1605 struct kretprobe_trace_entry_head *field;
1606 struct trace_seq *s = &iter->seq;
1607 struct trace_probe *tp;
1608
1609 field = (struct kretprobe_trace_entry_head *)iter->ent;
1610 tp = trace_probe_primary_from_call(
1611 container_of(event, struct trace_event_call, event));
1612 if (WARN_ON_ONCE(!tp))
1613 goto out;
1614
1615 trace_seq_printf(s, fmt: "%s: (", trace_probe_name(tp));
1616
1617 if (!seq_print_ip_sym(s, ip: field->ret_ip, sym_flags: flags | TRACE_ITER_SYM_OFFSET))
1618 goto out;
1619
1620 trace_seq_puts(s, str: " <- ");
1621
1622 if (!seq_print_ip_sym(s, ip: field->func, sym_flags: flags & ~TRACE_ITER_SYM_OFFSET))
1623 goto out;
1624
1625 trace_seq_putc(s, c: ')');
1626
1627 if (trace_probe_print_args(s, args: tp->args, nr_args: tp->nr_args,
1628 data: (u8 *)&field[1], field) < 0)
1629 goto out;
1630
1631 trace_seq_putc(s, c: '\n');
1632
1633 out:
1634 return trace_handle_return(s);
1635}
1636
1637
1638static int kprobe_event_define_fields(struct trace_event_call *event_call)
1639{
1640 int ret;
1641 struct kprobe_trace_entry_head field;
1642 struct trace_probe *tp;
1643
1644 tp = trace_probe_primary_from_call(call: event_call);
1645 if (WARN_ON_ONCE(!tp))
1646 return -ENOENT;
1647
1648 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1649
1650 return traceprobe_define_arg_fields(event_call, offset: sizeof(field), tp);
1651}
1652
1653static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1654{
1655 int ret;
1656 struct kretprobe_trace_entry_head field;
1657 struct trace_probe *tp;
1658
1659 tp = trace_probe_primary_from_call(call: event_call);
1660 if (WARN_ON_ONCE(!tp))
1661 return -ENOENT;
1662
1663 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1664 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1665
1666 return traceprobe_define_arg_fields(event_call, offset: sizeof(field), tp);
1667}
1668
1669#ifdef CONFIG_PERF_EVENTS
1670
1671/* Kprobe profile handler */
1672static int
1673kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1674{
1675 struct trace_event_call *call = trace_probe_event_call(tp: &tk->tp);
1676 struct kprobe_trace_entry_head *entry;
1677 struct hlist_head *head;
1678 int size, __size, dsize;
1679 int rctx;
1680
1681 if (bpf_prog_array_valid(call)) {
1682 unsigned long orig_ip = instruction_pointer(regs);
1683 int ret;
1684
1685 ret = trace_call_bpf(call, ctx: regs);
1686
1687 /*
1688 * We need to check and see if we modified the pc of the
1689 * pt_regs, and if so return 1 so that we don't do the
1690 * single stepping.
1691 */
1692 if (orig_ip != instruction_pointer(regs))
1693 return 1;
1694 if (!ret)
1695 return 0;
1696 }
1697
1698 head = this_cpu_ptr(call->perf_events);
1699 if (hlist_empty(h: head))
1700 return 0;
1701
1702 dsize = __get_data_size(tp: &tk->tp, regs, NULL);
1703 __size = sizeof(*entry) + tk->tp.size + dsize;
1704 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1705 size -= sizeof(u32);
1706
1707 entry = perf_trace_buf_alloc(size, NULL, rctxp: &rctx);
1708 if (!entry)
1709 return 0;
1710
1711 entry->ip = (unsigned long)tk->rp.kp.addr;
1712 memset(s: &entry[1], c: 0, n: dsize);
1713 store_trace_args(data: &entry[1], tp: &tk->tp, rec: regs, NULL, header_size: sizeof(*entry), maxlen: dsize);
1714 perf_trace_buf_submit(raw_data: entry, size, rctx, type: call->event.type, count: 1, regs,
1715 head, NULL);
1716 return 0;
1717}
1718NOKPROBE_SYMBOL(kprobe_perf_func);
1719
1720/* Kretprobe profile handler */
1721static void
1722kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1723 struct pt_regs *regs)
1724{
1725 struct trace_event_call *call = trace_probe_event_call(tp: &tk->tp);
1726 struct kretprobe_trace_entry_head *entry;
1727 struct hlist_head *head;
1728 int size, __size, dsize;
1729 int rctx;
1730
1731 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, ctx: regs))
1732 return;
1733
1734 head = this_cpu_ptr(call->perf_events);
1735 if (hlist_empty(h: head))
1736 return;
1737
1738 dsize = __get_data_size(tp: &tk->tp, regs, edata: ri->data);
1739 __size = sizeof(*entry) + tk->tp.size + dsize;
1740 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1741 size -= sizeof(u32);
1742
1743 entry = perf_trace_buf_alloc(size, NULL, rctxp: &rctx);
1744 if (!entry)
1745 return;
1746
1747 entry->func = (unsigned long)tk->rp.kp.addr;
1748 entry->ret_ip = get_kretprobe_retaddr(ri);
1749 store_trace_args(data: &entry[1], tp: &tk->tp, rec: regs, edata: ri->data, header_size: sizeof(*entry), maxlen: dsize);
1750 perf_trace_buf_submit(raw_data: entry, size, rctx, type: call->event.type, count: 1, regs,
1751 head, NULL);
1752}
1753NOKPROBE_SYMBOL(kretprobe_perf_func);
1754
1755int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1756 const char **symbol, u64 *probe_offset,
1757 u64 *probe_addr, unsigned long *missed,
1758 bool perf_type_tracepoint)
1759{
1760 const char *pevent = trace_event_name(call: event->tp_event);
1761 const char *group = event->tp_event->class->system;
1762 struct trace_kprobe *tk;
1763
1764 if (perf_type_tracepoint)
1765 tk = find_trace_kprobe(event: pevent, group);
1766 else
1767 tk = trace_kprobe_primary_from_call(call: event->tp_event);
1768 if (!tk)
1769 return -EINVAL;
1770
1771 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1772 : BPF_FD_TYPE_KPROBE;
1773 *probe_offset = tk->rp.kp.offset;
1774 *probe_addr = kallsyms_show_value(current_cred()) ?
1775 (unsigned long)tk->rp.kp.addr : 0;
1776 *symbol = tk->symbol;
1777 if (missed)
1778 *missed = trace_kprobe_missed(tk);
1779 return 0;
1780}
1781#endif /* CONFIG_PERF_EVENTS */
1782
1783/*
1784 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1785 *
1786 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1787 * lockless, but we can't race with this __init function.
1788 */
1789static int kprobe_register(struct trace_event_call *event,
1790 enum trace_reg type, void *data)
1791{
1792 struct trace_event_file *file = data;
1793
1794 switch (type) {
1795 case TRACE_REG_REGISTER:
1796 return enable_trace_kprobe(call: event, file);
1797 case TRACE_REG_UNREGISTER:
1798 return disable_trace_kprobe(call: event, file);
1799
1800#ifdef CONFIG_PERF_EVENTS
1801 case TRACE_REG_PERF_REGISTER:
1802 return enable_trace_kprobe(call: event, NULL);
1803 case TRACE_REG_PERF_UNREGISTER:
1804 return disable_trace_kprobe(call: event, NULL);
1805 case TRACE_REG_PERF_OPEN:
1806 case TRACE_REG_PERF_CLOSE:
1807 case TRACE_REG_PERF_ADD:
1808 case TRACE_REG_PERF_DEL:
1809 return 0;
1810#endif
1811 }
1812 return 0;
1813}
1814
1815static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1816{
1817 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1818 unsigned int flags = trace_probe_load_flag(tp: &tk->tp);
1819 int ret = 0;
1820
1821 raw_cpu_inc(*tk->nhit);
1822
1823 if (flags & TP_FLAG_TRACE)
1824 kprobe_trace_func(tk, regs);
1825#ifdef CONFIG_PERF_EVENTS
1826 if (flags & TP_FLAG_PROFILE)
1827 ret = kprobe_perf_func(tk, regs);
1828#endif
1829 return ret;
1830}
1831NOKPROBE_SYMBOL(kprobe_dispatcher);
1832
1833static int
1834kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1835{
1836 struct kretprobe *rp = get_kretprobe(ri);
1837 struct trace_kprobe *tk;
1838 unsigned int flags;
1839
1840 /*
1841 * There is a small chance that get_kretprobe(ri) returns NULL when
1842 * the kretprobe is unregister on another CPU between kretprobe's
1843 * trampoline_handler and this function.
1844 */
1845 if (unlikely(!rp))
1846 return 0;
1847
1848 tk = container_of(rp, struct trace_kprobe, rp);
1849 raw_cpu_inc(*tk->nhit);
1850
1851 flags = trace_probe_load_flag(tp: &tk->tp);
1852 if (flags & TP_FLAG_TRACE)
1853 kretprobe_trace_func(tk, ri, regs);
1854#ifdef CONFIG_PERF_EVENTS
1855 if (flags & TP_FLAG_PROFILE)
1856 kretprobe_perf_func(tk, ri, regs);
1857#endif
1858 return 0; /* We don't tweak kernel, so just return 0 */
1859}
1860NOKPROBE_SYMBOL(kretprobe_dispatcher);
1861
1862static struct trace_event_functions kretprobe_funcs = {
1863 .trace = print_kretprobe_event
1864};
1865
1866static struct trace_event_functions kprobe_funcs = {
1867 .trace = print_kprobe_event
1868};
1869
1870static struct trace_event_fields kretprobe_fields_array[] = {
1871 { .type = TRACE_FUNCTION_TYPE,
1872 .define_fields = kretprobe_event_define_fields },
1873 {}
1874};
1875
1876static struct trace_event_fields kprobe_fields_array[] = {
1877 { .type = TRACE_FUNCTION_TYPE,
1878 .define_fields = kprobe_event_define_fields },
1879 {}
1880};
1881
1882static inline void init_trace_event_call(struct trace_kprobe *tk)
1883{
1884 struct trace_event_call *call = trace_probe_event_call(tp: &tk->tp);
1885
1886 if (trace_kprobe_is_return(tk)) {
1887 call->event.funcs = &kretprobe_funcs;
1888 call->class->fields_array = kretprobe_fields_array;
1889 } else {
1890 call->event.funcs = &kprobe_funcs;
1891 call->class->fields_array = kprobe_fields_array;
1892 }
1893
1894 call->flags = TRACE_EVENT_FL_KPROBE;
1895 call->class->reg = kprobe_register;
1896}
1897
1898static int register_kprobe_event(struct trace_kprobe *tk)
1899{
1900 init_trace_event_call(tk);
1901
1902 return trace_probe_register_event_call(tp: &tk->tp);
1903}
1904
1905static int unregister_kprobe_event(struct trace_kprobe *tk)
1906{
1907 return trace_probe_unregister_event_call(tp: &tk->tp);
1908}
1909
1910#ifdef CONFIG_PERF_EVENTS
1911
1912/* create a trace_kprobe, but don't add it to global lists */
1913struct trace_event_call *
1914create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1915 bool is_return)
1916{
1917 enum probe_print_type ptype;
1918 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL;
1919 int ret;
1920 char *event;
1921
1922 if (func) {
1923 ret = validate_probe_symbol(symbol: func);
1924 if (ret)
1925 return ERR_PTR(error: ret);
1926 }
1927
1928 /*
1929 * local trace_kprobes are not added to dyn_event, so they are never
1930 * searched in find_trace_kprobe(). Therefore, there is no concern of
1931 * duplicated name here.
1932 */
1933 event = func ? func : "DUMMY_EVENT";
1934
1935 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, addr: (void *)addr, symbol: func,
1936 offs, maxactive: 0 /* maxactive */, nargs: 0 /* nargs */,
1937 is_return);
1938
1939 if (IS_ERR(ptr: tk)) {
1940 pr_info("Failed to allocate trace_probe.(%d)\n",
1941 (int)PTR_ERR(tk));
1942 return ERR_CAST(ptr: tk);
1943 }
1944
1945 init_trace_event_call(tk);
1946
1947 ptype = trace_kprobe_is_return(tk) ?
1948 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1949 if (traceprobe_set_print_fmt(tp: &tk->tp, ptype) < 0)
1950 return ERR_PTR(error: -ENOMEM);
1951
1952 ret = __register_trace_kprobe(tk);
1953 if (ret < 0)
1954 return ERR_PTR(error: ret);
1955
1956 return trace_probe_event_call(tp: &(no_free_ptr(tk)->tp));
1957}
1958
1959void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1960{
1961 struct trace_kprobe *tk;
1962
1963 tk = trace_kprobe_primary_from_call(call: event_call);
1964 if (unlikely(!tk))
1965 return;
1966
1967 if (trace_probe_is_enabled(tp: &tk->tp)) {
1968 WARN_ON(1);
1969 return;
1970 }
1971
1972 __unregister_trace_kprobe(tk);
1973
1974 free_trace_kprobe(tk);
1975}
1976#endif /* CONFIG_PERF_EVENTS */
1977
1978static __init void enable_boot_kprobe_events(void)
1979{
1980 struct trace_array *tr = top_trace_array();
1981 struct trace_event_file *file;
1982 struct trace_kprobe *tk;
1983 struct dyn_event *pos;
1984
1985 guard(mutex)(T: &event_mutex);
1986 for_each_trace_kprobe(tk, pos) {
1987 list_for_each_entry(file, &tr->events, list)
1988 if (file->event_call == trace_probe_event_call(tp: &tk->tp))
1989 trace_event_enable_disable(file, enable: 1, soft_disable: 0);
1990 }
1991}
1992
1993static __init void setup_boot_kprobe_events(void)
1994{
1995 char *p, *cmd = kprobe_boot_events_buf;
1996 int ret;
1997
1998 strreplace(str: kprobe_boot_events_buf, old: ',', new: ' ');
1999
2000 while (cmd && *cmd != '\0') {
2001 p = strchr(cmd, ';');
2002 if (p)
2003 *p++ = '\0';
2004
2005 ret = create_or_delete_trace_kprobe(raw_command: cmd);
2006 if (ret)
2007 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
2008
2009 cmd = p;
2010 }
2011
2012 enable_boot_kprobe_events();
2013}
2014
2015/*
2016 * Register dynevent at core_initcall. This allows kernel to setup kprobe
2017 * events in postcore_initcall without tracefs.
2018 */
2019static __init int init_kprobe_trace_early(void)
2020{
2021 int ret;
2022
2023 ret = dyn_event_register(ops: &trace_kprobe_ops);
2024 if (ret)
2025 return ret;
2026
2027 if (trace_kprobe_register_module_notifier())
2028 return -EINVAL;
2029
2030 return 0;
2031}
2032core_initcall(init_kprobe_trace_early);
2033
2034/* Make a tracefs interface for controlling probe points */
2035static __init int init_kprobe_trace(void)
2036{
2037 int ret;
2038
2039 ret = tracing_init_dentry();
2040 if (ret)
2041 return 0;
2042
2043 /* Event list interface */
2044 trace_create_file(name: "kprobe_events", TRACE_MODE_WRITE,
2045 NULL, NULL, fops: &kprobe_events_ops);
2046
2047 /* Profile interface */
2048 trace_create_file(name: "kprobe_profile", TRACE_MODE_READ,
2049 NULL, NULL, fops: &kprobe_profile_ops);
2050
2051 setup_boot_kprobe_events();
2052
2053 return 0;
2054}
2055fs_initcall(init_kprobe_trace);
2056
2057
2058#ifdef CONFIG_FTRACE_STARTUP_TEST
2059static __init struct trace_event_file *
2060find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
2061{
2062 struct trace_event_file *file;
2063
2064 list_for_each_entry(file, &tr->events, list)
2065 if (file->event_call == trace_probe_event_call(&tk->tp))
2066 return file;
2067
2068 return NULL;
2069}
2070
2071/*
2072 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
2073 * stage, we can do this lockless.
2074 */
2075static __init int kprobe_trace_self_tests_init(void)
2076{
2077 int ret, warn = 0;
2078 int (*target)(int, int, int, int, int, int);
2079 struct trace_kprobe *tk;
2080 struct trace_event_file *file;
2081
2082 if (tracing_is_disabled())
2083 return -ENODEV;
2084
2085 if (tracing_selftest_disabled)
2086 return 0;
2087
2088 target = kprobe_trace_selftest_target;
2089
2090 pr_info("Testing kprobe tracing: ");
2091
2092 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2093 if (WARN_ONCE(ret, "error on probing function entry.")) {
2094 warn++;
2095 } else {
2096 /* Enable trace point */
2097 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2098 if (WARN_ONCE(tk == NULL, "error on probing function entry.")) {
2099 warn++;
2100 } else {
2101 file = find_trace_probe_file(tk, top_trace_array());
2102 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2103 warn++;
2104 } else
2105 enable_trace_kprobe(
2106 trace_probe_event_call(&tk->tp), file);
2107 }
2108 }
2109
2110 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2111 if (WARN_ONCE(ret, "error on probing function return.")) {
2112 warn++;
2113 } else {
2114 /* Enable trace point */
2115 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2116 if (WARN_ONCE(tk == NULL, "error on getting 2nd new probe.")) {
2117 warn++;
2118 } else {
2119 file = find_trace_probe_file(tk, top_trace_array());
2120 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2121 warn++;
2122 } else
2123 enable_trace_kprobe(
2124 trace_probe_event_call(&tk->tp), file);
2125 }
2126 }
2127
2128 if (warn)
2129 goto end;
2130
2131 ret = target(1, 2, 3, 4, 5, 6);
2132
2133 /*
2134 * Not expecting an error here, the check is only to prevent the
2135 * optimizer from removing the call to target() as otherwise there
2136 * are no side-effects and the call is never performed.
2137 */
2138 if (ret != 21)
2139 warn++;
2140
2141 /* Disable trace points before removing it */
2142 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2143 if (WARN_ONCE(tk == NULL, "error on getting test probe.")) {
2144 warn++;
2145 } else {
2146 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2147 "incorrect number of testprobe hits."))
2148 warn++;
2149
2150 file = find_trace_probe_file(tk, top_trace_array());
2151 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2152 warn++;
2153 } else
2154 disable_trace_kprobe(
2155 trace_probe_event_call(&tk->tp), file);
2156 }
2157
2158 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2159 if (WARN_ONCE(tk == NULL, "error on getting 2nd test probe.")) {
2160 warn++;
2161 } else {
2162 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2163 "incorrect number of testprobe2 hits."))
2164 warn++;
2165
2166 file = find_trace_probe_file(tk, top_trace_array());
2167 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2168 warn++;
2169 } else
2170 disable_trace_kprobe(
2171 trace_probe_event_call(&tk->tp), file);
2172 }
2173
2174 ret = create_or_delete_trace_kprobe("-:testprobe");
2175 if (WARN_ONCE(ret, "error on deleting a probe."))
2176 warn++;
2177
2178 ret = create_or_delete_trace_kprobe("-:testprobe2");
2179 if (WARN_ONCE(ret, "error on deleting a probe."))
2180 warn++;
2181
2182
2183end:
2184 /*
2185 * Wait for the optimizer work to finish. Otherwise it might fiddle
2186 * with probes in already freed __init text.
2187 */
2188 wait_for_kprobe_optimizer();
2189 if (warn)
2190 pr_cont("NG: Some tests are failed. Please check them.\n");
2191 else
2192 pr_cont("OK\n");
2193 return 0;
2194}
2195
2196late_initcall(kprobe_trace_self_tests_init);
2197
2198#endif
2199