tracing/kprobes: Fail to unregister if probe event files are in use
[linux-3.10.git] / kernel / trace / trace_kprobe.c
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  */
30 struct trace_probe {
31         struct list_head        list;
32         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
33         unsigned long           nhit;
34         unsigned int            flags;  /* For TP_FLAG_* */
35         const char              *symbol;        /* symbol name */
36         struct ftrace_event_class       class;
37         struct ftrace_event_call        call;
38         struct ftrace_event_file * __rcu *files;
39         ssize_t                 size;           /* trace entry size */
40         unsigned int            nr_args;
41         struct probe_arg        args[];
42 };
43
44 #define SIZEOF_TRACE_PROBE(n)                   \
45         (offsetof(struct trace_probe, args) +   \
46         (sizeof(struct probe_arg) * (n)))
47
48
49 static __kprobes bool trace_probe_is_return(struct trace_probe *tp)
50 {
51         return tp->rp.handler != NULL;
52 }
53
54 static __kprobes const char *trace_probe_symbol(struct trace_probe *tp)
55 {
56         return tp->symbol ? tp->symbol : "unknown";
57 }
58
59 static __kprobes unsigned long trace_probe_offset(struct trace_probe *tp)
60 {
61         return tp->rp.kp.offset;
62 }
63
64 static __kprobes bool trace_probe_is_enabled(struct trace_probe *tp)
65 {
66         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
67 }
68
69 static __kprobes bool trace_probe_is_registered(struct trace_probe *tp)
70 {
71         return !!(tp->flags & TP_FLAG_REGISTERED);
72 }
73
74 static __kprobes bool trace_probe_has_gone(struct trace_probe *tp)
75 {
76         return !!(kprobe_gone(&tp->rp.kp));
77 }
78
79 static __kprobes bool trace_probe_within_module(struct trace_probe *tp,
80                                                 struct module *mod)
81 {
82         int len = strlen(mod->name);
83         const char *name = trace_probe_symbol(tp);
84         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
85 }
86
87 static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
88 {
89         return !!strchr(trace_probe_symbol(tp), ':');
90 }
91
92 static int register_probe_event(struct trace_probe *tp);
93 static int unregister_probe_event(struct trace_probe *tp);
94
95 static DEFINE_MUTEX(probe_lock);
96 static LIST_HEAD(probe_list);
97
98 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
99 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
100                                 struct pt_regs *regs);
101
102 /*
103  * Allocate new trace_probe and initialize it (including kprobes).
104  */
105 static struct trace_probe *alloc_trace_probe(const char *group,
106                                              const char *event,
107                                              void *addr,
108                                              const char *symbol,
109                                              unsigned long offs,
110                                              int nargs, bool is_return)
111 {
112         struct trace_probe *tp;
113         int ret = -ENOMEM;
114
115         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
116         if (!tp)
117                 return ERR_PTR(ret);
118
119         if (symbol) {
120                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
121                 if (!tp->symbol)
122                         goto error;
123                 tp->rp.kp.symbol_name = tp->symbol;
124                 tp->rp.kp.offset = offs;
125         } else
126                 tp->rp.kp.addr = addr;
127
128         if (is_return)
129                 tp->rp.handler = kretprobe_dispatcher;
130         else
131                 tp->rp.kp.pre_handler = kprobe_dispatcher;
132
133         if (!event || !is_good_name(event)) {
134                 ret = -EINVAL;
135                 goto error;
136         }
137
138         tp->call.class = &tp->class;
139         tp->call.name = kstrdup(event, GFP_KERNEL);
140         if (!tp->call.name)
141                 goto error;
142
143         if (!group || !is_good_name(group)) {
144                 ret = -EINVAL;
145                 goto error;
146         }
147
148         tp->class.system = kstrdup(group, GFP_KERNEL);
149         if (!tp->class.system)
150                 goto error;
151
152         INIT_LIST_HEAD(&tp->list);
153         return tp;
154 error:
155         kfree(tp->call.name);
156         kfree(tp->symbol);
157         kfree(tp);
158         return ERR_PTR(ret);
159 }
160
161 static void free_trace_probe(struct trace_probe *tp)
162 {
163         int i;
164
165         for (i = 0; i < tp->nr_args; i++)
166                 traceprobe_free_probe_arg(&tp->args[i]);
167
168         kfree(tp->call.class->system);
169         kfree(tp->call.name);
170         kfree(tp->symbol);
171         kfree(tp);
172 }
173
174 static struct trace_probe *find_trace_probe(const char *event,
175                                             const char *group)
176 {
177         struct trace_probe *tp;
178
179         list_for_each_entry(tp, &probe_list, list)
180                 if (strcmp(tp->call.name, event) == 0 &&
181                     strcmp(tp->call.class->system, group) == 0)
182                         return tp;
183         return NULL;
184 }
185
186 static int trace_probe_nr_files(struct trace_probe *tp)
187 {
188         struct ftrace_event_file **file;
189         int ret = 0;
190
191         /*
192          * Since all tp->files updater is protected by probe_enable_lock,
193          * we don't need to lock an rcu_read_lock.
194          */
195         file = rcu_dereference_raw(tp->files);
196         if (file)
197                 while (*(file++))
198                         ret++;
199
200         return ret;
201 }
202
203 static DEFINE_MUTEX(probe_enable_lock);
204
205 /*
206  * Enable trace_probe
207  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
208  */
209 static int
210 enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
211 {
212         int ret = 0;
213
214         mutex_lock(&probe_enable_lock);
215
216         if (file) {
217                 struct ftrace_event_file **new, **old;
218                 int n = trace_probe_nr_files(tp);
219
220                 old = rcu_dereference_raw(tp->files);
221                 /* 1 is for new one and 1 is for stopper */
222                 new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
223                               GFP_KERNEL);
224                 if (!new) {
225                         ret = -ENOMEM;
226                         goto out_unlock;
227                 }
228                 memcpy(new, old, n * sizeof(struct ftrace_event_file *));
229                 new[n] = file;
230                 /* The last one keeps a NULL */
231
232                 rcu_assign_pointer(tp->files, new);
233                 tp->flags |= TP_FLAG_TRACE;
234
235                 if (old) {
236                         /* Make sure the probe is done with old files */
237                         synchronize_sched();
238                         kfree(old);
239                 }
240         } else
241                 tp->flags |= TP_FLAG_PROFILE;
242
243         if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
244             !trace_probe_has_gone(tp)) {
245                 if (trace_probe_is_return(tp))
246                         ret = enable_kretprobe(&tp->rp);
247                 else
248                         ret = enable_kprobe(&tp->rp.kp);
249         }
250
251  out_unlock:
252         mutex_unlock(&probe_enable_lock);
253
254         return ret;
255 }
256
257 static int
258 trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
259 {
260         struct ftrace_event_file **files;
261         int i;
262
263         /*
264          * Since all tp->files updater is protected by probe_enable_lock,
265          * we don't need to lock an rcu_read_lock.
266          */
267         files = rcu_dereference_raw(tp->files);
268         if (files) {
269                 for (i = 0; files[i]; i++)
270                         if (files[i] == file)
271                                 return i;
272         }
273
274         return -1;
275 }
276
277 /*
278  * Disable trace_probe
279  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
280  */
281 static int
282 disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
283 {
284         struct ftrace_event_file **old = NULL;
285         int wait = 0;
286         int ret = 0;
287
288         mutex_lock(&probe_enable_lock);
289
290         if (file) {
291                 struct ftrace_event_file **new, **old;
292                 int n = trace_probe_nr_files(tp);
293                 int i, j;
294
295                 old = rcu_dereference_raw(tp->files);
296                 if (n == 0 || trace_probe_file_index(tp, file) < 0) {
297                         ret = -EINVAL;
298                         goto out_unlock;
299                 }
300
301                 if (n == 1) {   /* Remove the last file */
302                         tp->flags &= ~TP_FLAG_TRACE;
303                         new = NULL;
304                 } else {
305                         new = kzalloc(n * sizeof(struct ftrace_event_file *),
306                                       GFP_KERNEL);
307                         if (!new) {
308                                 ret = -ENOMEM;
309                                 goto out_unlock;
310                         }
311
312                         /* This copy & check loop copies the NULL stopper too */
313                         for (i = 0, j = 0; j < n && i < n + 1; i++)
314                                 if (old[i] != file)
315                                         new[j++] = old[i];
316                 }
317
318                 rcu_assign_pointer(tp->files, new);
319                 wait = 1;
320         } else
321                 tp->flags &= ~TP_FLAG_PROFILE;
322
323         if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
324                 if (trace_probe_is_return(tp))
325                         disable_kretprobe(&tp->rp);
326                 else
327                         disable_kprobe(&tp->rp.kp);
328                 wait = 1;
329         }
330
331  out_unlock:
332         mutex_unlock(&probe_enable_lock);
333
334         if (wait) {
335                 /*
336                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
337                  * to ensure disabled (all running handlers are finished).
338                  * This is not only for kfree(), but also the caller,
339                  * trace_remove_event_call() supposes it for releasing
340                  * event_call related objects, which will be accessed in
341                  * the kprobe_trace_func/kretprobe_trace_func.
342                  */
343                 synchronize_sched();
344                 kfree(old);     /* Ignored if link == NULL */
345         }
346
347         return ret;
348 }
349
350 /* Internal register function - just handle k*probes and flags */
351 static int __register_trace_probe(struct trace_probe *tp)
352 {
353         int i, ret;
354
355         if (trace_probe_is_registered(tp))
356                 return -EINVAL;
357
358         for (i = 0; i < tp->nr_args; i++)
359                 traceprobe_update_arg(&tp->args[i]);
360
361         /* Set/clear disabled flag according to tp->flag */
362         if (trace_probe_is_enabled(tp))
363                 tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
364         else
365                 tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
366
367         if (trace_probe_is_return(tp))
368                 ret = register_kretprobe(&tp->rp);
369         else
370                 ret = register_kprobe(&tp->rp.kp);
371
372         if (ret == 0)
373                 tp->flags |= TP_FLAG_REGISTERED;
374         else {
375                 pr_warning("Could not insert probe at %s+%lu: %d\n",
376                            trace_probe_symbol(tp), trace_probe_offset(tp), ret);
377                 if (ret == -ENOENT && trace_probe_is_on_module(tp)) {
378                         pr_warning("This probe might be able to register after"
379                                    "target module is loaded. Continue.\n");
380                         ret = 0;
381                 } else if (ret == -EILSEQ) {
382                         pr_warning("Probing address(0x%p) is not an "
383                                    "instruction boundary.\n",
384                                    tp->rp.kp.addr);
385                         ret = -EINVAL;
386                 }
387         }
388
389         return ret;
390 }
391
392 /* Internal unregister function - just handle k*probes and flags */
393 static void __unregister_trace_probe(struct trace_probe *tp)
394 {
395         if (trace_probe_is_registered(tp)) {
396                 if (trace_probe_is_return(tp))
397                         unregister_kretprobe(&tp->rp);
398                 else
399                         unregister_kprobe(&tp->rp.kp);
400                 tp->flags &= ~TP_FLAG_REGISTERED;
401                 /* Cleanup kprobe for reuse */
402                 if (tp->rp.kp.symbol_name)
403                         tp->rp.kp.addr = NULL;
404         }
405 }
406
407 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
408 static int unregister_trace_probe(struct trace_probe *tp)
409 {
410         /* Enabled event can not be unregistered */
411         if (trace_probe_is_enabled(tp))
412                 return -EBUSY;
413
414         /* Will fail if probe is being used by ftrace or perf */
415         if (unregister_probe_event(tp))
416                 return -EBUSY;
417
418         __unregister_trace_probe(tp);
419         list_del(&tp->list);
420
421         return 0;
422 }
423
424 /* Register a trace_probe and probe_event */
425 static int register_trace_probe(struct trace_probe *tp)
426 {
427         struct trace_probe *old_tp;
428         int ret;
429
430         mutex_lock(&probe_lock);
431
432         /* Delete old (same name) event if exist */
433         old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
434         if (old_tp) {
435                 ret = unregister_trace_probe(old_tp);
436                 if (ret < 0)
437                         goto end;
438                 free_trace_probe(old_tp);
439         }
440
441         /* Register new event */
442         ret = register_probe_event(tp);
443         if (ret) {
444                 pr_warning("Failed to register probe event(%d)\n", ret);
445                 goto end;
446         }
447
448         /* Register k*probe */
449         ret = __register_trace_probe(tp);
450         if (ret < 0)
451                 unregister_probe_event(tp);
452         else
453                 list_add_tail(&tp->list, &probe_list);
454
455 end:
456         mutex_unlock(&probe_lock);
457         return ret;
458 }
459
460 /* Module notifier call back, checking event on the module */
461 static int trace_probe_module_callback(struct notifier_block *nb,
462                                        unsigned long val, void *data)
463 {
464         struct module *mod = data;
465         struct trace_probe *tp;
466         int ret;
467
468         if (val != MODULE_STATE_COMING)
469                 return NOTIFY_DONE;
470
471         /* Update probes on coming module */
472         mutex_lock(&probe_lock);
473         list_for_each_entry(tp, &probe_list, list) {
474                 if (trace_probe_within_module(tp, mod)) {
475                         /* Don't need to check busy - this should have gone. */
476                         __unregister_trace_probe(tp);
477                         ret = __register_trace_probe(tp);
478                         if (ret)
479                                 pr_warning("Failed to re-register probe %s on"
480                                            "%s: %d\n",
481                                            tp->call.name, mod->name, ret);
482                 }
483         }
484         mutex_unlock(&probe_lock);
485
486         return NOTIFY_DONE;
487 }
488
489 static struct notifier_block trace_probe_module_nb = {
490         .notifier_call = trace_probe_module_callback,
491         .priority = 1   /* Invoked after kprobe module callback */
492 };
493
494 static int create_trace_probe(int argc, char **argv)
495 {
496         /*
497          * Argument syntax:
498          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
499          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
500          * Fetch args:
501          *  $retval     : fetch return value
502          *  $stack      : fetch stack address
503          *  $stackN     : fetch Nth of stack (N:0-)
504          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
505          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
506          *  %REG        : fetch register REG
507          * Dereferencing memory fetch:
508          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
509          * Alias name of args:
510          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
511          * Type of args:
512          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
513          */
514         struct trace_probe *tp;
515         int i, ret = 0;
516         bool is_return = false, is_delete = false;
517         char *symbol = NULL, *event = NULL, *group = NULL;
518         char *arg;
519         unsigned long offset = 0;
520         void *addr = NULL;
521         char buf[MAX_EVENT_NAME_LEN];
522
523         /* argc must be >= 1 */
524         if (argv[0][0] == 'p')
525                 is_return = false;
526         else if (argv[0][0] == 'r')
527                 is_return = true;
528         else if (argv[0][0] == '-')
529                 is_delete = true;
530         else {
531                 pr_info("Probe definition must be started with 'p', 'r' or"
532                         " '-'.\n");
533                 return -EINVAL;
534         }
535
536         if (argv[0][1] == ':') {
537                 event = &argv[0][2];
538                 if (strchr(event, '/')) {
539                         group = event;
540                         event = strchr(group, '/') + 1;
541                         event[-1] = '\0';
542                         if (strlen(group) == 0) {
543                                 pr_info("Group name is not specified\n");
544                                 return -EINVAL;
545                         }
546                 }
547                 if (strlen(event) == 0) {
548                         pr_info("Event name is not specified\n");
549                         return -EINVAL;
550                 }
551         }
552         if (!group)
553                 group = KPROBE_EVENT_SYSTEM;
554
555         if (is_delete) {
556                 if (!event) {
557                         pr_info("Delete command needs an event name.\n");
558                         return -EINVAL;
559                 }
560                 mutex_lock(&probe_lock);
561                 tp = find_trace_probe(event, group);
562                 if (!tp) {
563                         mutex_unlock(&probe_lock);
564                         pr_info("Event %s/%s doesn't exist.\n", group, event);
565                         return -ENOENT;
566                 }
567                 /* delete an event */
568                 ret = unregister_trace_probe(tp);
569                 if (ret == 0)
570                         free_trace_probe(tp);
571                 mutex_unlock(&probe_lock);
572                 return ret;
573         }
574
575         if (argc < 2) {
576                 pr_info("Probe point is not specified.\n");
577                 return -EINVAL;
578         }
579         if (isdigit(argv[1][0])) {
580                 if (is_return) {
581                         pr_info("Return probe point must be a symbol.\n");
582                         return -EINVAL;
583                 }
584                 /* an address specified */
585                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
586                 if (ret) {
587                         pr_info("Failed to parse address.\n");
588                         return ret;
589                 }
590         } else {
591                 /* a symbol specified */
592                 symbol = argv[1];
593                 /* TODO: support .init module functions */
594                 ret = traceprobe_split_symbol_offset(symbol, &offset);
595                 if (ret) {
596                         pr_info("Failed to parse symbol.\n");
597                         return ret;
598                 }
599                 if (offset && is_return) {
600                         pr_info("Return probe must be used without offset.\n");
601                         return -EINVAL;
602                 }
603         }
604         argc -= 2; argv += 2;
605
606         /* setup a probe */
607         if (!event) {
608                 /* Make a new event name */
609                 if (symbol)
610                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
611                                  is_return ? 'r' : 'p', symbol, offset);
612                 else
613                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
614                                  is_return ? 'r' : 'p', addr);
615                 event = buf;
616         }
617         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
618                                is_return);
619         if (IS_ERR(tp)) {
620                 pr_info("Failed to allocate trace_probe.(%d)\n",
621                         (int)PTR_ERR(tp));
622                 return PTR_ERR(tp);
623         }
624
625         /* parse arguments */
626         ret = 0;
627         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
628                 /* Increment count for freeing args in error case */
629                 tp->nr_args++;
630
631                 /* Parse argument name */
632                 arg = strchr(argv[i], '=');
633                 if (arg) {
634                         *arg++ = '\0';
635                         tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
636                 } else {
637                         arg = argv[i];
638                         /* If argument name is omitted, set "argN" */
639                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
640                         tp->args[i].name = kstrdup(buf, GFP_KERNEL);
641                 }
642
643                 if (!tp->args[i].name) {
644                         pr_info("Failed to allocate argument[%d] name.\n", i);
645                         ret = -ENOMEM;
646                         goto error;
647                 }
648
649                 if (!is_good_name(tp->args[i].name)) {
650                         pr_info("Invalid argument[%d] name: %s\n",
651                                 i, tp->args[i].name);
652                         ret = -EINVAL;
653                         goto error;
654                 }
655
656                 if (traceprobe_conflict_field_name(tp->args[i].name,
657                                                         tp->args, i)) {
658                         pr_info("Argument[%d] name '%s' conflicts with "
659                                 "another field.\n", i, argv[i]);
660                         ret = -EINVAL;
661                         goto error;
662                 }
663
664                 /* Parse fetch argument */
665                 ret = traceprobe_parse_probe_arg(arg, &tp->size, &tp->args[i],
666                                                 is_return, true);
667                 if (ret) {
668                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
669                         goto error;
670                 }
671         }
672
673         ret = register_trace_probe(tp);
674         if (ret)
675                 goto error;
676         return 0;
677
678 error:
679         free_trace_probe(tp);
680         return ret;
681 }
682
683 static int release_all_trace_probes(void)
684 {
685         struct trace_probe *tp;
686         int ret = 0;
687
688         mutex_lock(&probe_lock);
689         /* Ensure no probe is in use. */
690         list_for_each_entry(tp, &probe_list, list)
691                 if (trace_probe_is_enabled(tp)) {
692                         ret = -EBUSY;
693                         goto end;
694                 }
695         /* TODO: Use batch unregistration */
696         while (!list_empty(&probe_list)) {
697                 tp = list_entry(probe_list.next, struct trace_probe, list);
698                 ret = unregister_trace_probe(tp);
699                 if (ret)
700                         goto end;
701                 free_trace_probe(tp);
702         }
703
704 end:
705         mutex_unlock(&probe_lock);
706
707         return ret;
708 }
709
710 /* Probes listing interfaces */
711 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
712 {
713         mutex_lock(&probe_lock);
714         return seq_list_start(&probe_list, *pos);
715 }
716
717 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
718 {
719         return seq_list_next(v, &probe_list, pos);
720 }
721
722 static void probes_seq_stop(struct seq_file *m, void *v)
723 {
724         mutex_unlock(&probe_lock);
725 }
726
727 static int probes_seq_show(struct seq_file *m, void *v)
728 {
729         struct trace_probe *tp = v;
730         int i;
731
732         seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p');
733         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
734
735         if (!tp->symbol)
736                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
737         else if (tp->rp.kp.offset)
738                 seq_printf(m, " %s+%u", trace_probe_symbol(tp),
739                            tp->rp.kp.offset);
740         else
741                 seq_printf(m, " %s", trace_probe_symbol(tp));
742
743         for (i = 0; i < tp->nr_args; i++)
744                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
745         seq_printf(m, "\n");
746
747         return 0;
748 }
749
750 static const struct seq_operations probes_seq_op = {
751         .start  = probes_seq_start,
752         .next   = probes_seq_next,
753         .stop   = probes_seq_stop,
754         .show   = probes_seq_show
755 };
756
757 static int probes_open(struct inode *inode, struct file *file)
758 {
759         int ret;
760
761         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
762                 ret = release_all_trace_probes();
763                 if (ret < 0)
764                         return ret;
765         }
766
767         return seq_open(file, &probes_seq_op);
768 }
769
770 static ssize_t probes_write(struct file *file, const char __user *buffer,
771                             size_t count, loff_t *ppos)
772 {
773         return traceprobe_probes_write(file, buffer, count, ppos,
774                         create_trace_probe);
775 }
776
777 static const struct file_operations kprobe_events_ops = {
778         .owner          = THIS_MODULE,
779         .open           = probes_open,
780         .read           = seq_read,
781         .llseek         = seq_lseek,
782         .release        = seq_release,
783         .write          = probes_write,
784 };
785
786 /* Probes profiling interfaces */
787 static int probes_profile_seq_show(struct seq_file *m, void *v)
788 {
789         struct trace_probe *tp = v;
790
791         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
792                    tp->rp.kp.nmissed);
793
794         return 0;
795 }
796
797 static const struct seq_operations profile_seq_op = {
798         .start  = probes_seq_start,
799         .next   = probes_seq_next,
800         .stop   = probes_seq_stop,
801         .show   = probes_profile_seq_show
802 };
803
804 static int profile_open(struct inode *inode, struct file *file)
805 {
806         return seq_open(file, &profile_seq_op);
807 }
808
809 static const struct file_operations kprobe_profile_ops = {
810         .owner          = THIS_MODULE,
811         .open           = profile_open,
812         .read           = seq_read,
813         .llseek         = seq_lseek,
814         .release        = seq_release,
815 };
816
817 /* Sum up total data length for dynamic arraies (strings) */
818 static __kprobes int __get_data_size(struct trace_probe *tp,
819                                      struct pt_regs *regs)
820 {
821         int i, ret = 0;
822         u32 len;
823
824         for (i = 0; i < tp->nr_args; i++)
825                 if (unlikely(tp->args[i].fetch_size.fn)) {
826                         call_fetch(&tp->args[i].fetch_size, regs, &len);
827                         ret += len;
828                 }
829
830         return ret;
831 }
832
833 /* Store the value of each argument */
834 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
835                                        struct pt_regs *regs,
836                                        u8 *data, int maxlen)
837 {
838         int i;
839         u32 end = tp->size;
840         u32 *dl;        /* Data (relative) location */
841
842         for (i = 0; i < tp->nr_args; i++) {
843                 if (unlikely(tp->args[i].fetch_size.fn)) {
844                         /*
845                          * First, we set the relative location and
846                          * maximum data length to *dl
847                          */
848                         dl = (u32 *)(data + tp->args[i].offset);
849                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
850                         /* Then try to fetch string or dynamic array data */
851                         call_fetch(&tp->args[i].fetch, regs, dl);
852                         /* Reduce maximum length */
853                         end += get_rloc_len(*dl);
854                         maxlen -= get_rloc_len(*dl);
855                         /* Trick here, convert data_rloc to data_loc */
856                         *dl = convert_rloc_to_loc(*dl,
857                                  ent_size + tp->args[i].offset);
858                 } else
859                         /* Just fetching data normally */
860                         call_fetch(&tp->args[i].fetch, regs,
861                                    data + tp->args[i].offset);
862         }
863 }
864
865 /* Kprobe handler */
866 static __kprobes void
867 __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
868                     struct ftrace_event_file *ftrace_file)
869 {
870         struct kprobe_trace_entry_head *entry;
871         struct ring_buffer_event *event;
872         struct ring_buffer *buffer;
873         int size, dsize, pc;
874         unsigned long irq_flags;
875         struct ftrace_event_call *call = &tp->call;
876
877         WARN_ON(call != ftrace_file->event_call);
878
879         if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
880                 return;
881
882         local_save_flags(irq_flags);
883         pc = preempt_count();
884
885         dsize = __get_data_size(tp, regs);
886         size = sizeof(*entry) + tp->size + dsize;
887
888         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
889                                                 call->event.type,
890                                                 size, irq_flags, pc);
891         if (!event)
892                 return;
893
894         entry = ring_buffer_event_data(event);
895         entry->ip = (unsigned long)tp->rp.kp.addr;
896         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
897
898         if (!filter_current_check_discard(buffer, call, entry, event))
899                 trace_buffer_unlock_commit_regs(buffer, event,
900                                                 irq_flags, pc, regs);
901 }
902
903 static __kprobes void
904 kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
905 {
906         /*
907          * Note: preempt is already disabled around the kprobe handler.
908          * However, we still need an smp_read_barrier_depends() corresponding
909          * to smp_wmb() in rcu_assign_pointer() to access the pointer.
910          */
911         struct ftrace_event_file **file = rcu_dereference_raw(tp->files);
912
913         if (unlikely(!file))
914                 return;
915
916         while (*file) {
917                 __kprobe_trace_func(tp, regs, *file);
918                 file++;
919         }
920 }
921
922 /* Kretprobe handler */
923 static __kprobes void
924 __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
925                        struct pt_regs *regs,
926                        struct ftrace_event_file *ftrace_file)
927 {
928         struct kretprobe_trace_entry_head *entry;
929         struct ring_buffer_event *event;
930         struct ring_buffer *buffer;
931         int size, pc, dsize;
932         unsigned long irq_flags;
933         struct ftrace_event_call *call = &tp->call;
934
935         WARN_ON(call != ftrace_file->event_call);
936
937         if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
938                 return;
939
940         local_save_flags(irq_flags);
941         pc = preempt_count();
942
943         dsize = __get_data_size(tp, regs);
944         size = sizeof(*entry) + tp->size + dsize;
945
946         event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
947                                                 call->event.type,
948                                                 size, irq_flags, pc);
949         if (!event)
950                 return;
951
952         entry = ring_buffer_event_data(event);
953         entry->func = (unsigned long)tp->rp.kp.addr;
954         entry->ret_ip = (unsigned long)ri->ret_addr;
955         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
956
957         if (!filter_current_check_discard(buffer, call, entry, event))
958                 trace_buffer_unlock_commit_regs(buffer, event,
959                                                 irq_flags, pc, regs);
960 }
961
962 static __kprobes void
963 kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
964                      struct pt_regs *regs)
965 {
966         /*
967          * Note: preempt is already disabled around the kprobe handler.
968          * However, we still need an smp_read_barrier_depends() corresponding
969          * to smp_wmb() in rcu_assign_pointer() to access the pointer.
970          */
971         struct ftrace_event_file **file = rcu_dereference_raw(tp->files);
972
973         if (unlikely(!file))
974                 return;
975
976         while (*file) {
977                 __kretprobe_trace_func(tp, ri, regs, *file);
978                 file++;
979         }
980 }
981
982 /* Event entry printers */
983 static enum print_line_t
984 print_kprobe_event(struct trace_iterator *iter, int flags,
985                    struct trace_event *event)
986 {
987         struct kprobe_trace_entry_head *field;
988         struct trace_seq *s = &iter->seq;
989         struct trace_probe *tp;
990         u8 *data;
991         int i;
992
993         field = (struct kprobe_trace_entry_head *)iter->ent;
994         tp = container_of(event, struct trace_probe, call.event);
995
996         if (!trace_seq_printf(s, "%s: (", tp->call.name))
997                 goto partial;
998
999         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1000                 goto partial;
1001
1002         if (!trace_seq_puts(s, ")"))
1003                 goto partial;
1004
1005         data = (u8 *)&field[1];
1006         for (i = 0; i < tp->nr_args; i++)
1007                 if (!tp->args[i].type->print(s, tp->args[i].name,
1008                                              data + tp->args[i].offset, field))
1009                         goto partial;
1010
1011         if (!trace_seq_puts(s, "\n"))
1012                 goto partial;
1013
1014         return TRACE_TYPE_HANDLED;
1015 partial:
1016         return TRACE_TYPE_PARTIAL_LINE;
1017 }
1018
1019 static enum print_line_t
1020 print_kretprobe_event(struct trace_iterator *iter, int flags,
1021                       struct trace_event *event)
1022 {
1023         struct kretprobe_trace_entry_head *field;
1024         struct trace_seq *s = &iter->seq;
1025         struct trace_probe *tp;
1026         u8 *data;
1027         int i;
1028
1029         field = (struct kretprobe_trace_entry_head *)iter->ent;
1030         tp = container_of(event, struct trace_probe, call.event);
1031
1032         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1033                 goto partial;
1034
1035         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1036                 goto partial;
1037
1038         if (!trace_seq_puts(s, " <- "))
1039                 goto partial;
1040
1041         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1042                 goto partial;
1043
1044         if (!trace_seq_puts(s, ")"))
1045                 goto partial;
1046
1047         data = (u8 *)&field[1];
1048         for (i = 0; i < tp->nr_args; i++)
1049                 if (!tp->args[i].type->print(s, tp->args[i].name,
1050                                              data + tp->args[i].offset, field))
1051                         goto partial;
1052
1053         if (!trace_seq_puts(s, "\n"))
1054                 goto partial;
1055
1056         return TRACE_TYPE_HANDLED;
1057 partial:
1058         return TRACE_TYPE_PARTIAL_LINE;
1059 }
1060
1061
1062 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1063 {
1064         int ret, i;
1065         struct kprobe_trace_entry_head field;
1066         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1067
1068         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1069         /* Set argument names as fields */
1070         for (i = 0; i < tp->nr_args; i++) {
1071                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1072                                          tp->args[i].name,
1073                                          sizeof(field) + tp->args[i].offset,
1074                                          tp->args[i].type->size,
1075                                          tp->args[i].type->is_signed,
1076                                          FILTER_OTHER);
1077                 if (ret)
1078                         return ret;
1079         }
1080         return 0;
1081 }
1082
1083 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1084 {
1085         int ret, i;
1086         struct kretprobe_trace_entry_head field;
1087         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1088
1089         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1090         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1091         /* Set argument names as fields */
1092         for (i = 0; i < tp->nr_args; i++) {
1093                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1094                                          tp->args[i].name,
1095                                          sizeof(field) + tp->args[i].offset,
1096                                          tp->args[i].type->size,
1097                                          tp->args[i].type->is_signed,
1098                                          FILTER_OTHER);
1099                 if (ret)
1100                         return ret;
1101         }
1102         return 0;
1103 }
1104
1105 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1106 {
1107         int i;
1108         int pos = 0;
1109
1110         const char *fmt, *arg;
1111
1112         if (!trace_probe_is_return(tp)) {
1113                 fmt = "(%lx)";
1114                 arg = "REC->" FIELD_STRING_IP;
1115         } else {
1116                 fmt = "(%lx <- %lx)";
1117                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1118         }
1119
1120         /* When len=0, we just calculate the needed length */
1121 #define LEN_OR_ZERO (len ? len - pos : 0)
1122
1123         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1124
1125         for (i = 0; i < tp->nr_args; i++) {
1126                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1127                                 tp->args[i].name, tp->args[i].type->fmt);
1128         }
1129
1130         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1131
1132         for (i = 0; i < tp->nr_args; i++) {
1133                 if (strcmp(tp->args[i].type->name, "string") == 0)
1134                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1135                                         ", __get_str(%s)",
1136                                         tp->args[i].name);
1137                 else
1138                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1139                                         tp->args[i].name);
1140         }
1141
1142 #undef LEN_OR_ZERO
1143
1144         /* return the length of print_fmt */
1145         return pos;
1146 }
1147
1148 static int set_print_fmt(struct trace_probe *tp)
1149 {
1150         int len;
1151         char *print_fmt;
1152
1153         /* First: called with 0 length to calculate the needed length */
1154         len = __set_print_fmt(tp, NULL, 0);
1155         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1156         if (!print_fmt)
1157                 return -ENOMEM;
1158
1159         /* Second: actually write the @print_fmt */
1160         __set_print_fmt(tp, print_fmt, len + 1);
1161         tp->call.print_fmt = print_fmt;
1162
1163         return 0;
1164 }
1165
1166 #ifdef CONFIG_PERF_EVENTS
1167
1168 /* Kprobe profile handler */
1169 static __kprobes void
1170 kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
1171 {
1172         struct ftrace_event_call *call = &tp->call;
1173         struct kprobe_trace_entry_head *entry;
1174         struct hlist_head *head;
1175         int size, __size, dsize;
1176         int rctx;
1177
1178         dsize = __get_data_size(tp, regs);
1179         __size = sizeof(*entry) + tp->size + dsize;
1180         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1181         size -= sizeof(u32);
1182         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1183                      "profile buffer not large enough"))
1184                 return;
1185
1186         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1187         if (!entry)
1188                 return;
1189
1190         entry->ip = (unsigned long)tp->rp.kp.addr;
1191         memset(&entry[1], 0, dsize);
1192         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1193
1194         head = this_cpu_ptr(call->perf_events);
1195         perf_trace_buf_submit(entry, size, rctx,
1196                                         entry->ip, 1, regs, head, NULL);
1197 }
1198
1199 /* Kretprobe profile handler */
1200 static __kprobes void
1201 kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
1202                     struct pt_regs *regs)
1203 {
1204         struct ftrace_event_call *call = &tp->call;
1205         struct kretprobe_trace_entry_head *entry;
1206         struct hlist_head *head;
1207         int size, __size, dsize;
1208         int rctx;
1209
1210         dsize = __get_data_size(tp, regs);
1211         __size = sizeof(*entry) + tp->size + dsize;
1212         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1213         size -= sizeof(u32);
1214         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1215                      "profile buffer not large enough"))
1216                 return;
1217
1218         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1219         if (!entry)
1220                 return;
1221
1222         entry->func = (unsigned long)tp->rp.kp.addr;
1223         entry->ret_ip = (unsigned long)ri->ret_addr;
1224         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1225
1226         head = this_cpu_ptr(call->perf_events);
1227         perf_trace_buf_submit(entry, size, rctx,
1228                                         entry->ret_ip, 1, regs, head, NULL);
1229 }
1230 #endif  /* CONFIG_PERF_EVENTS */
1231
1232 static __kprobes
1233 int kprobe_register(struct ftrace_event_call *event,
1234                     enum trace_reg type, void *data)
1235 {
1236         struct trace_probe *tp = (struct trace_probe *)event->data;
1237         struct ftrace_event_file *file = data;
1238
1239         switch (type) {
1240         case TRACE_REG_REGISTER:
1241                 return enable_trace_probe(tp, file);
1242         case TRACE_REG_UNREGISTER:
1243                 return disable_trace_probe(tp, file);
1244
1245 #ifdef CONFIG_PERF_EVENTS
1246         case TRACE_REG_PERF_REGISTER:
1247                 return enable_trace_probe(tp, NULL);
1248         case TRACE_REG_PERF_UNREGISTER:
1249                 return disable_trace_probe(tp, NULL);
1250         case TRACE_REG_PERF_OPEN:
1251         case TRACE_REG_PERF_CLOSE:
1252         case TRACE_REG_PERF_ADD:
1253         case TRACE_REG_PERF_DEL:
1254                 return 0;
1255 #endif
1256         }
1257         return 0;
1258 }
1259
1260 static __kprobes
1261 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1262 {
1263         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1264
1265         tp->nhit++;
1266
1267         if (tp->flags & TP_FLAG_TRACE)
1268                 kprobe_trace_func(tp, regs);
1269 #ifdef CONFIG_PERF_EVENTS
1270         if (tp->flags & TP_FLAG_PROFILE)
1271                 kprobe_perf_func(tp, regs);
1272 #endif
1273         return 0;       /* We don't tweek kernel, so just return 0 */
1274 }
1275
1276 static __kprobes
1277 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1278 {
1279         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1280
1281         tp->nhit++;
1282
1283         if (tp->flags & TP_FLAG_TRACE)
1284                 kretprobe_trace_func(tp, ri, regs);
1285 #ifdef CONFIG_PERF_EVENTS
1286         if (tp->flags & TP_FLAG_PROFILE)
1287                 kretprobe_perf_func(tp, ri, regs);
1288 #endif
1289         return 0;       /* We don't tweek kernel, so just return 0 */
1290 }
1291
1292 static struct trace_event_functions kretprobe_funcs = {
1293         .trace          = print_kretprobe_event
1294 };
1295
1296 static struct trace_event_functions kprobe_funcs = {
1297         .trace          = print_kprobe_event
1298 };
1299
1300 static int register_probe_event(struct trace_probe *tp)
1301 {
1302         struct ftrace_event_call *call = &tp->call;
1303         int ret;
1304
1305         /* Initialize ftrace_event_call */
1306         INIT_LIST_HEAD(&call->class->fields);
1307         if (trace_probe_is_return(tp)) {
1308                 call->event.funcs = &kretprobe_funcs;
1309                 call->class->define_fields = kretprobe_event_define_fields;
1310         } else {
1311                 call->event.funcs = &kprobe_funcs;
1312                 call->class->define_fields = kprobe_event_define_fields;
1313         }
1314         if (set_print_fmt(tp) < 0)
1315                 return -ENOMEM;
1316         ret = register_ftrace_event(&call->event);
1317         if (!ret) {
1318                 kfree(call->print_fmt);
1319                 return -ENODEV;
1320         }
1321         call->flags = 0;
1322         call->class->reg = kprobe_register;
1323         call->data = tp;
1324         ret = trace_add_event_call(call);
1325         if (ret) {
1326                 pr_info("Failed to register kprobe event: %s\n", call->name);
1327                 kfree(call->print_fmt);
1328                 unregister_ftrace_event(&call->event);
1329         }
1330         return ret;
1331 }
1332
1333 static int unregister_probe_event(struct trace_probe *tp)
1334 {
1335         int ret;
1336
1337         /* tp->event is unregistered in trace_remove_event_call() */
1338         ret = trace_remove_event_call(&tp->call);
1339         if (!ret)
1340                 kfree(tp->call.print_fmt);
1341         return ret;
1342 }
1343
1344 /* Make a debugfs interface for controlling probe points */
1345 static __init int init_kprobe_trace(void)
1346 {
1347         struct dentry *d_tracer;
1348         struct dentry *entry;
1349
1350         if (register_module_notifier(&trace_probe_module_nb))
1351                 return -EINVAL;
1352
1353         d_tracer = tracing_init_dentry();
1354         if (!d_tracer)
1355                 return 0;
1356
1357         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1358                                     NULL, &kprobe_events_ops);
1359
1360         /* Event list interface */
1361         if (!entry)
1362                 pr_warning("Could not create debugfs "
1363                            "'kprobe_events' entry\n");
1364
1365         /* Profile interface */
1366         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1367                                     NULL, &kprobe_profile_ops);
1368
1369         if (!entry)
1370                 pr_warning("Could not create debugfs "
1371                            "'kprobe_profile' entry\n");
1372         return 0;
1373 }
1374 fs_initcall(init_kprobe_trace);
1375
1376
1377 #ifdef CONFIG_FTRACE_STARTUP_TEST
1378
1379 /*
1380  * The "__used" keeps gcc from removing the function symbol
1381  * from the kallsyms table.
1382  */
1383 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1384                                                int a4, int a5, int a6)
1385 {
1386         return a1 + a2 + a3 + a4 + a5 + a6;
1387 }
1388
1389 static struct ftrace_event_file *
1390 find_trace_probe_file(struct trace_probe *tp, struct trace_array *tr)
1391 {
1392         struct ftrace_event_file *file;
1393
1394         list_for_each_entry(file, &tr->events, list)
1395                 if (file->event_call == &tp->call)
1396                         return file;
1397
1398         return NULL;
1399 }
1400
1401 static __init int kprobe_trace_self_tests_init(void)
1402 {
1403         int ret, warn = 0;
1404         int (*target)(int, int, int, int, int, int);
1405         struct trace_probe *tp;
1406         struct ftrace_event_file *file;
1407
1408         target = kprobe_trace_selftest_target;
1409
1410         pr_info("Testing kprobe tracing: ");
1411
1412         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1413                                   "$stack $stack0 +0($stack)",
1414                                   create_trace_probe);
1415         if (WARN_ON_ONCE(ret)) {
1416                 pr_warn("error on probing function entry.\n");
1417                 warn++;
1418         } else {
1419                 /* Enable trace point */
1420                 tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
1421                 if (WARN_ON_ONCE(tp == NULL)) {
1422                         pr_warn("error on getting new probe.\n");
1423                         warn++;
1424                 } else {
1425                         file = find_trace_probe_file(tp, 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_probe(tp, file);
1431                 }
1432         }
1433
1434         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1435                                   "$retval", create_trace_probe);
1436         if (WARN_ON_ONCE(ret)) {
1437                 pr_warn("error on probing function return.\n");
1438                 warn++;
1439         } else {
1440                 /* Enable trace point */
1441                 tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
1442                 if (WARN_ON_ONCE(tp == NULL)) {
1443                         pr_warn("error on getting 2nd new probe.\n");
1444                         warn++;
1445                 } else {
1446                         file = find_trace_probe_file(tp, top_trace_array());
1447                         if (WARN_ON_ONCE(file == NULL)) {
1448                                 pr_warn("error on getting probe file.\n");
1449                                 warn++;
1450                         } else
1451                                 enable_trace_probe(tp, file);
1452                 }
1453         }
1454
1455         if (warn)
1456                 goto end;
1457
1458         ret = target(1, 2, 3, 4, 5, 6);
1459
1460         /* Disable trace points before removing it */
1461         tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
1462         if (WARN_ON_ONCE(tp == NULL)) {
1463                 pr_warn("error on getting test probe.\n");
1464                 warn++;
1465         } else {
1466                 file = find_trace_probe_file(tp, top_trace_array());
1467                 if (WARN_ON_ONCE(file == NULL)) {
1468                         pr_warn("error on getting probe file.\n");
1469                         warn++;
1470                 } else
1471                         disable_trace_probe(tp, file);
1472         }
1473
1474         tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
1475         if (WARN_ON_ONCE(tp == NULL)) {
1476                 pr_warn("error on getting 2nd test probe.\n");
1477                 warn++;
1478         } else {
1479                 file = find_trace_probe_file(tp, top_trace_array());
1480                 if (WARN_ON_ONCE(file == NULL)) {
1481                         pr_warn("error on getting probe file.\n");
1482                         warn++;
1483                 } else
1484                         disable_trace_probe(tp, file);
1485         }
1486
1487         ret = traceprobe_command("-:testprobe", create_trace_probe);
1488         if (WARN_ON_ONCE(ret)) {
1489                 pr_warn("error on deleting a probe.\n");
1490                 warn++;
1491         }
1492
1493         ret = traceprobe_command("-:testprobe2", create_trace_probe);
1494         if (WARN_ON_ONCE(ret)) {
1495                 pr_warn("error on deleting a probe.\n");
1496                 warn++;
1497         }
1498
1499 end:
1500         release_all_trace_probes();
1501         if (warn)
1502                 pr_cont("NG: Some tests are failed. Please check them.\n");
1503         else
1504                 pr_cont("OK\n");
1505         return 0;
1506 }
1507
1508 late_initcall(kprobe_trace_self_tests_init);
1509
1510 #endif