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Linux/kernel/trace/trace_kprobe.c

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  1 /*
  2  * Kprobes-based tracing events
  3  *
  4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful,
 11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13  * GNU General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU General Public License
 16  * along with this program; if not, write to the Free Software
 17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 18  */
 19 
 20 #include <linux/module.h>
 21 #include <linux/uaccess.h>
 22 
 23 #include "trace_probe.h"
 24 
 25 #define KPROBE_EVENT_SYSTEM "kprobes"
 26 
 27 /**
 28  * Kprobe event core functions
 29  */
 30 struct trace_kprobe {
 31         struct list_head        list;
 32         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 33         unsigned long           nhit;
 34         const char              *symbol;        /* symbol name */
 35         struct trace_probe      tp;
 36 };
 37 
 38 #define SIZEOF_TRACE_KPROBE(n)                          \
 39         (offsetof(struct trace_kprobe, tp.args) +       \
 40         (sizeof(struct probe_arg) * (n)))
 41 
 42 
 43 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
 44 {
 45         return tk->rp.handler != NULL;
 46 }
 47 
 48 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
 49 {
 50         return tk->symbol ? tk->symbol : "unknown";
 51 }
 52 
 53 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
 54 {
 55         return tk->rp.kp.offset;
 56 }
 57 
 58 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 59 {
 60         return !!(kprobe_gone(&tk->rp.kp));
 61 }
 62 
 63 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 64                                                  struct module *mod)
 65 {
 66         int len = strlen(mod->name);
 67         const char *name = trace_kprobe_symbol(tk);
 68         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
 69 }
 70 
 71 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
 72 {
 73         return !!strchr(trace_kprobe_symbol(tk), ':');
 74 }
 75 
 76 static int register_kprobe_event(struct trace_kprobe *tk);
 77 static int unregister_kprobe_event(struct trace_kprobe *tk);
 78 
 79 static DEFINE_MUTEX(probe_lock);
 80 static LIST_HEAD(probe_list);
 81 
 82 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 83 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 84                                 struct pt_regs *regs);
 85 
 86 /* Memory fetching by symbol */
 87 struct symbol_cache {
 88         char            *symbol;
 89         long            offset;
 90         unsigned long   addr;
 91 };
 92 
 93 unsigned long update_symbol_cache(struct symbol_cache *sc)
 94 {
 95         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 96 
 97         if (sc->addr)
 98                 sc->addr += sc->offset;
 99 
100         return sc->addr;
101 }
102 
103 void free_symbol_cache(struct symbol_cache *sc)
104 {
105         kfree(sc->symbol);
106         kfree(sc);
107 }
108 
109 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
110 {
111         struct symbol_cache *sc;
112 
113         if (!sym || strlen(sym) == 0)
114                 return NULL;
115 
116         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
117         if (!sc)
118                 return NULL;
119 
120         sc->symbol = kstrdup(sym, GFP_KERNEL);
121         if (!sc->symbol) {
122                 kfree(sc);
123                 return NULL;
124         }
125         sc->offset = offset;
126         update_symbol_cache(sc);
127 
128         return sc;
129 }
130 
131 /*
132  * Kprobes-specific fetch functions
133  */
134 #define DEFINE_FETCH_stack(type)                                        \
135 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
136                                           void *offset, void *dest)     \
137 {                                                                       \
138         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
139                                 (unsigned int)((unsigned long)offset)); \
140 }                                                                       \
141 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
142 
143 DEFINE_BASIC_FETCH_FUNCS(stack)
144 /* No string on the stack entry */
145 #define fetch_stack_string      NULL
146 #define fetch_stack_string_size NULL
147 
148 #define DEFINE_FETCH_memory(type)                                       \
149 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
150                                           void *addr, void *dest)       \
151 {                                                                       \
152         type retval;                                                    \
153         if (probe_kernel_address(addr, retval))                         \
154                 *(type *)dest = 0;                                      \
155         else                                                            \
156                 *(type *)dest = retval;                                 \
157 }                                                                       \
158 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
159 
160 DEFINE_BASIC_FETCH_FUNCS(memory)
161 /*
162  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
163  * length and relative data location.
164  */
165 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
166                                             void *addr, void *dest)
167 {
168         int maxlen = get_rloc_len(*(u32 *)dest);
169         u8 *dst = get_rloc_data(dest);
170         long ret;
171 
172         if (!maxlen)
173                 return;
174 
175         /*
176          * Try to get string again, since the string can be changed while
177          * probing.
178          */
179         ret = strncpy_from_unsafe(dst, addr, maxlen);
180 
181         if (ret < 0) {  /* Failed to fetch string */
182                 dst[0] = '\0';
183                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
184         } else {
185                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
186         }
187 }
188 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
189 
190 /* Return the length of string -- including null terminal byte */
191 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
192                                                  void *addr, void *dest)
193 {
194         mm_segment_t old_fs;
195         int ret, len = 0;
196         u8 c;
197 
198         old_fs = get_fs();
199         set_fs(KERNEL_DS);
200         pagefault_disable();
201 
202         do {
203                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
204                 len++;
205         } while (c && ret == 0 && len < MAX_STRING_SIZE);
206 
207         pagefault_enable();
208         set_fs(old_fs);
209 
210         if (ret < 0)    /* Failed to check the length */
211                 *(u32 *)dest = 0;
212         else
213                 *(u32 *)dest = len;
214 }
215 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
216 
217 #define DEFINE_FETCH_symbol(type)                                       \
218 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
219 {                                                                       \
220         struct symbol_cache *sc = data;                                 \
221         if (sc->addr)                                                   \
222                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
223         else                                                            \
224                 *(type *)dest = 0;                                      \
225 }                                                                       \
226 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
227 
228 DEFINE_BASIC_FETCH_FUNCS(symbol)
229 DEFINE_FETCH_symbol(string)
230 DEFINE_FETCH_symbol(string_size)
231 
232 /* kprobes don't support file_offset fetch methods */
233 #define fetch_file_offset_u8            NULL
234 #define fetch_file_offset_u16           NULL
235 #define fetch_file_offset_u32           NULL
236 #define fetch_file_offset_u64           NULL
237 #define fetch_file_offset_string        NULL
238 #define fetch_file_offset_string_size   NULL
239 
240 /* Fetch type information table */
241 static const struct fetch_type kprobes_fetch_type_table[] = {
242         /* Special types */
243         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
244                                         sizeof(u32), 1, "__data_loc char[]"),
245         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
246                                         string_size, sizeof(u32), 0, "u32"),
247         /* Basic types */
248         ASSIGN_FETCH_TYPE(u8,  u8,  0),
249         ASSIGN_FETCH_TYPE(u16, u16, 0),
250         ASSIGN_FETCH_TYPE(u32, u32, 0),
251         ASSIGN_FETCH_TYPE(u64, u64, 0),
252         ASSIGN_FETCH_TYPE(s8,  u8,  1),
253         ASSIGN_FETCH_TYPE(s16, u16, 1),
254         ASSIGN_FETCH_TYPE(s32, u32, 1),
255         ASSIGN_FETCH_TYPE(s64, u64, 1),
256 
257         ASSIGN_FETCH_TYPE_END
258 };
259 
260 /*
261  * Allocate new trace_probe and initialize it (including kprobes).
262  */
263 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
264                                              const char *event,
265                                              void *addr,
266                                              const char *symbol,
267                                              unsigned long offs,
268                                              int nargs, bool is_return)
269 {
270         struct trace_kprobe *tk;
271         int ret = -ENOMEM;
272 
273         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
274         if (!tk)
275                 return ERR_PTR(ret);
276 
277         if (symbol) {
278                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
279                 if (!tk->symbol)
280                         goto error;
281                 tk->rp.kp.symbol_name = tk->symbol;
282                 tk->rp.kp.offset = offs;
283         } else
284                 tk->rp.kp.addr = addr;
285 
286         if (is_return)
287                 tk->rp.handler = kretprobe_dispatcher;
288         else
289                 tk->rp.kp.pre_handler = kprobe_dispatcher;
290 
291         if (!event || !is_good_name(event)) {
292                 ret = -EINVAL;
293                 goto error;
294         }
295 
296         tk->tp.call.class = &tk->tp.class;
297         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
298         if (!tk->tp.call.name)
299                 goto error;
300 
301         if (!group || !is_good_name(group)) {
302                 ret = -EINVAL;
303                 goto error;
304         }
305 
306         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
307         if (!tk->tp.class.system)
308                 goto error;
309 
310         INIT_LIST_HEAD(&tk->list);
311         INIT_LIST_HEAD(&tk->tp.files);
312         return tk;
313 error:
314         kfree(tk->tp.call.name);
315         kfree(tk->symbol);
316         kfree(tk);
317         return ERR_PTR(ret);
318 }
319 
320 static void free_trace_kprobe(struct trace_kprobe *tk)
321 {
322         int i;
323 
324         for (i = 0; i < tk->tp.nr_args; i++)
325                 traceprobe_free_probe_arg(&tk->tp.args[i]);
326 
327         kfree(tk->tp.call.class->system);
328         kfree(tk->tp.call.name);
329         kfree(tk->symbol);
330         kfree(tk);
331 }
332 
333 static struct trace_kprobe *find_trace_kprobe(const char *event,
334                                               const char *group)
335 {
336         struct trace_kprobe *tk;
337 
338         list_for_each_entry(tk, &probe_list, list)
339                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
340                     strcmp(tk->tp.call.class->system, group) == 0)
341                         return tk;
342         return NULL;
343 }
344 
345 /*
346  * Enable trace_probe
347  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
348  */
349 static int
350 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
351 {
352         int ret = 0;
353 
354         if (file) {
355                 struct event_file_link *link;
356 
357                 link = kmalloc(sizeof(*link), GFP_KERNEL);
358                 if (!link) {
359                         ret = -ENOMEM;
360                         goto out;
361                 }
362 
363                 link->file = file;
364                 list_add_tail_rcu(&link->list, &tk->tp.files);
365 
366                 tk->tp.flags |= TP_FLAG_TRACE;
367         } else
368                 tk->tp.flags |= TP_FLAG_PROFILE;
369 
370         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
371                 if (trace_kprobe_is_return(tk))
372                         ret = enable_kretprobe(&tk->rp);
373                 else
374                         ret = enable_kprobe(&tk->rp.kp);
375         }
376  out:
377         return ret;
378 }
379 
380 /*
381  * Disable trace_probe
382  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
383  */
384 static int
385 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
386 {
387         struct event_file_link *link = NULL;
388         int wait = 0;
389         int ret = 0;
390 
391         if (file) {
392                 link = find_event_file_link(&tk->tp, file);
393                 if (!link) {
394                         ret = -EINVAL;
395                         goto out;
396                 }
397 
398                 list_del_rcu(&link->list);
399                 wait = 1;
400                 if (!list_empty(&tk->tp.files))
401                         goto out;
402 
403                 tk->tp.flags &= ~TP_FLAG_TRACE;
404         } else
405                 tk->tp.flags &= ~TP_FLAG_PROFILE;
406 
407         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
408                 if (trace_kprobe_is_return(tk))
409                         disable_kretprobe(&tk->rp);
410                 else
411                         disable_kprobe(&tk->rp.kp);
412                 wait = 1;
413         }
414  out:
415         if (wait) {
416                 /*
417                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
418                  * to ensure disabled (all running handlers are finished).
419                  * This is not only for kfree(), but also the caller,
420                  * trace_remove_event_call() supposes it for releasing
421                  * event_call related objects, which will be accessed in
422                  * the kprobe_trace_func/kretprobe_trace_func.
423                  */
424                 synchronize_sched();
425                 kfree(link);    /* Ignored if link == NULL */
426         }
427 
428         return ret;
429 }
430 
431 /* Internal register function - just handle k*probes and flags */
432 static int __register_trace_kprobe(struct trace_kprobe *tk)
433 {
434         int i, ret;
435 
436         if (trace_probe_is_registered(&tk->tp))
437                 return -EINVAL;
438 
439         for (i = 0; i < tk->tp.nr_args; i++)
440                 traceprobe_update_arg(&tk->tp.args[i]);
441 
442         /* Set/clear disabled flag according to tp->flag */
443         if (trace_probe_is_enabled(&tk->tp))
444                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
445         else
446                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
447 
448         if (trace_kprobe_is_return(tk))
449                 ret = register_kretprobe(&tk->rp);
450         else
451                 ret = register_kprobe(&tk->rp.kp);
452 
453         if (ret == 0)
454                 tk->tp.flags |= TP_FLAG_REGISTERED;
455         else {
456                 pr_warning("Could not insert probe at %s+%lu: %d\n",
457                            trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
458                 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
459                         pr_warning("This probe might be able to register after"
460                                    "target module is loaded. Continue.\n");
461                         ret = 0;
462                 } else if (ret == -EILSEQ) {
463                         pr_warning("Probing address(0x%p) is not an "
464                                    "instruction boundary.\n",
465                                    tk->rp.kp.addr);
466                         ret = -EINVAL;
467                 }
468         }
469 
470         return ret;
471 }
472 
473 /* Internal unregister function - just handle k*probes and flags */
474 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
475 {
476         if (trace_probe_is_registered(&tk->tp)) {
477                 if (trace_kprobe_is_return(tk))
478                         unregister_kretprobe(&tk->rp);
479                 else
480                         unregister_kprobe(&tk->rp.kp);
481                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
482                 /* Cleanup kprobe for reuse */
483                 if (tk->rp.kp.symbol_name)
484                         tk->rp.kp.addr = NULL;
485         }
486 }
487 
488 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
489 static int unregister_trace_kprobe(struct trace_kprobe *tk)
490 {
491         /* Enabled event can not be unregistered */
492         if (trace_probe_is_enabled(&tk->tp))
493                 return -EBUSY;
494 
495         /* Will fail if probe is being used by ftrace or perf */
496         if (unregister_kprobe_event(tk))
497                 return -EBUSY;
498 
499         __unregister_trace_kprobe(tk);
500         list_del(&tk->list);
501 
502         return 0;
503 }
504 
505 /* Register a trace_probe and probe_event */
506 static int register_trace_kprobe(struct trace_kprobe *tk)
507 {
508         struct trace_kprobe *old_tk;
509         int ret;
510 
511         mutex_lock(&probe_lock);
512 
513         /* Delete old (same name) event if exist */
514         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
515                         tk->tp.call.class->system);
516         if (old_tk) {
517                 ret = unregister_trace_kprobe(old_tk);
518                 if (ret < 0)
519                         goto end;
520                 free_trace_kprobe(old_tk);
521         }
522 
523         /* Register new event */
524         ret = register_kprobe_event(tk);
525         if (ret) {
526                 pr_warning("Failed to register probe event(%d)\n", ret);
527                 goto end;
528         }
529 
530         /* Register k*probe */
531         ret = __register_trace_kprobe(tk);
532         if (ret < 0)
533                 unregister_kprobe_event(tk);
534         else
535                 list_add_tail(&tk->list, &probe_list);
536 
537 end:
538         mutex_unlock(&probe_lock);
539         return ret;
540 }
541 
542 /* Module notifier call back, checking event on the module */
543 static int trace_kprobe_module_callback(struct notifier_block *nb,
544                                        unsigned long val, void *data)
545 {
546         struct module *mod = data;
547         struct trace_kprobe *tk;
548         int ret;
549 
550         if (val != MODULE_STATE_COMING)
551                 return NOTIFY_DONE;
552 
553         /* Update probes on coming module */
554         mutex_lock(&probe_lock);
555         list_for_each_entry(tk, &probe_list, list) {
556                 if (trace_kprobe_within_module(tk, mod)) {
557                         /* Don't need to check busy - this should have gone. */
558                         __unregister_trace_kprobe(tk);
559                         ret = __register_trace_kprobe(tk);
560                         if (ret)
561                                 pr_warning("Failed to re-register probe %s on"
562                                            "%s: %d\n",
563                                            trace_event_name(&tk->tp.call),
564                                            mod->name, ret);
565                 }
566         }
567         mutex_unlock(&probe_lock);
568 
569         return NOTIFY_DONE;
570 }
571 
572 static struct notifier_block trace_kprobe_module_nb = {
573         .notifier_call = trace_kprobe_module_callback,
574         .priority = 1   /* Invoked after kprobe module callback */
575 };
576 
577 static int create_trace_kprobe(int argc, char **argv)
578 {
579         /*
580          * Argument syntax:
581          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
582          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
583          * Fetch args:
584          *  $retval     : fetch return value
585          *  $stack      : fetch stack address
586          *  $stackN     : fetch Nth of stack (N:0-)
587          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
588          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
589          *  %REG        : fetch register REG
590          * Dereferencing memory fetch:
591          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
592          * Alias name of args:
593          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
594          * Type of args:
595          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
596          */
597         struct trace_kprobe *tk;
598         int i, ret = 0;
599         bool is_return = false, is_delete = false;
600         char *symbol = NULL, *event = NULL, *group = NULL;
601         char *arg;
602         unsigned long offset = 0;
603         void *addr = NULL;
604         char buf[MAX_EVENT_NAME_LEN];
605 
606         /* argc must be >= 1 */
607         if (argv[0][0] == 'p')
608                 is_return = false;
609         else if (argv[0][0] == 'r')
610                 is_return = true;
611         else if (argv[0][0] == '-')
612                 is_delete = true;
613         else {
614                 pr_info("Probe definition must be started with 'p', 'r' or"
615                         " '-'.\n");
616                 return -EINVAL;
617         }
618 
619         if (argv[0][1] == ':') {
620                 event = &argv[0][2];
621                 if (strchr(event, '/')) {
622                         group = event;
623                         event = strchr(group, '/') + 1;
624                         event[-1] = '\0';
625                         if (strlen(group) == 0) {
626                                 pr_info("Group name is not specified\n");
627                                 return -EINVAL;
628                         }
629                 }
630                 if (strlen(event) == 0) {
631                         pr_info("Event name is not specified\n");
632                         return -EINVAL;
633                 }
634         }
635         if (!group)
636                 group = KPROBE_EVENT_SYSTEM;
637 
638         if (is_delete) {
639                 if (!event) {
640                         pr_info("Delete command needs an event name.\n");
641                         return -EINVAL;
642                 }
643                 mutex_lock(&probe_lock);
644                 tk = find_trace_kprobe(event, group);
645                 if (!tk) {
646                         mutex_unlock(&probe_lock);
647                         pr_info("Event %s/%s doesn't exist.\n", group, event);
648                         return -ENOENT;
649                 }
650                 /* delete an event */
651                 ret = unregister_trace_kprobe(tk);
652                 if (ret == 0)
653                         free_trace_kprobe(tk);
654                 mutex_unlock(&probe_lock);
655                 return ret;
656         }
657 
658         if (argc < 2) {
659                 pr_info("Probe point is not specified.\n");
660                 return -EINVAL;
661         }
662         if (isdigit(argv[1][0])) {
663                 if (is_return) {
664                         pr_info("Return probe point must be a symbol.\n");
665                         return -EINVAL;
666                 }
667                 /* an address specified */
668                 ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
669                 if (ret) {
670                         pr_info("Failed to parse address.\n");
671                         return ret;
672                 }
673         } else {
674                 /* a symbol specified */
675                 symbol = argv[1];
676                 /* TODO: support .init module functions */
677                 ret = traceprobe_split_symbol_offset(symbol, &offset);
678                 if (ret) {
679                         pr_info("Failed to parse symbol.\n");
680                         return ret;
681                 }
682                 if (offset && is_return) {
683                         pr_info("Return probe must be used without offset.\n");
684                         return -EINVAL;
685                 }
686         }
687         argc -= 2; argv += 2;
688 
689         /* setup a probe */
690         if (!event) {
691                 /* Make a new event name */
692                 if (symbol)
693                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
694                                  is_return ? 'r' : 'p', symbol, offset);
695                 else
696                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
697                                  is_return ? 'r' : 'p', addr);
698                 event = buf;
699         }
700         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc,
701                                is_return);
702         if (IS_ERR(tk)) {
703                 pr_info("Failed to allocate trace_probe.(%d)\n",
704                         (int)PTR_ERR(tk));
705                 return PTR_ERR(tk);
706         }
707 
708         /* parse arguments */
709         ret = 0;
710         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
711                 struct probe_arg *parg = &tk->tp.args[i];
712 
713                 /* Increment count for freeing args in error case */
714                 tk->tp.nr_args++;
715 
716                 /* Parse argument name */
717                 arg = strchr(argv[i], '=');
718                 if (arg) {
719                         *arg++ = '\0';
720                         parg->name = kstrdup(argv[i], GFP_KERNEL);
721                 } else {
722                         arg = argv[i];
723                         /* If argument name is omitted, set "argN" */
724                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
725                         parg->name = kstrdup(buf, GFP_KERNEL);
726                 }
727 
728                 if (!parg->name) {
729                         pr_info("Failed to allocate argument[%d] name.\n", i);
730                         ret = -ENOMEM;
731                         goto error;
732                 }
733 
734                 if (!is_good_name(parg->name)) {
735                         pr_info("Invalid argument[%d] name: %s\n",
736                                 i, parg->name);
737                         ret = -EINVAL;
738                         goto error;
739                 }
740 
741                 if (traceprobe_conflict_field_name(parg->name,
742                                                         tk->tp.args, i)) {
743                         pr_info("Argument[%d] name '%s' conflicts with "
744                                 "another field.\n", i, argv[i]);
745                         ret = -EINVAL;
746                         goto error;
747                 }
748 
749                 /* Parse fetch argument */
750                 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
751                                                 is_return, true,
752                                                 kprobes_fetch_type_table);
753                 if (ret) {
754                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
755                         goto error;
756                 }
757         }
758 
759         ret = register_trace_kprobe(tk);
760         if (ret)
761                 goto error;
762         return 0;
763 
764 error:
765         free_trace_kprobe(tk);
766         return ret;
767 }
768 
769 static int release_all_trace_kprobes(void)
770 {
771         struct trace_kprobe *tk;
772         int ret = 0;
773 
774         mutex_lock(&probe_lock);
775         /* Ensure no probe is in use. */
776         list_for_each_entry(tk, &probe_list, list)
777                 if (trace_probe_is_enabled(&tk->tp)) {
778                         ret = -EBUSY;
779                         goto end;
780                 }
781         /* TODO: Use batch unregistration */
782         while (!list_empty(&probe_list)) {
783                 tk = list_entry(probe_list.next, struct trace_kprobe, list);
784                 ret = unregister_trace_kprobe(tk);
785                 if (ret)
786                         goto end;
787                 free_trace_kprobe(tk);
788         }
789 
790 end:
791         mutex_unlock(&probe_lock);
792 
793         return ret;
794 }
795 
796 /* Probes listing interfaces */
797 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
798 {
799         mutex_lock(&probe_lock);
800         return seq_list_start(&probe_list, *pos);
801 }
802 
803 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
804 {
805         return seq_list_next(v, &probe_list, pos);
806 }
807 
808 static void probes_seq_stop(struct seq_file *m, void *v)
809 {
810         mutex_unlock(&probe_lock);
811 }
812 
813 static int probes_seq_show(struct seq_file *m, void *v)
814 {
815         struct trace_kprobe *tk = v;
816         int i;
817 
818         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
819         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
820                         trace_event_name(&tk->tp.call));
821 
822         if (!tk->symbol)
823                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
824         else if (tk->rp.kp.offset)
825                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
826                            tk->rp.kp.offset);
827         else
828                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
829 
830         for (i = 0; i < tk->tp.nr_args; i++)
831                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
832         seq_putc(m, '\n');
833 
834         return 0;
835 }
836 
837 static const struct seq_operations probes_seq_op = {
838         .start  = probes_seq_start,
839         .next   = probes_seq_next,
840         .stop   = probes_seq_stop,
841         .show   = probes_seq_show
842 };
843 
844 static int probes_open(struct inode *inode, struct file *file)
845 {
846         int ret;
847 
848         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
849                 ret = release_all_trace_kprobes();
850                 if (ret < 0)
851                         return ret;
852         }
853 
854         return seq_open(file, &probes_seq_op);
855 }
856 
857 static ssize_t probes_write(struct file *file, const char __user *buffer,
858                             size_t count, loff_t *ppos)
859 {
860         return traceprobe_probes_write(file, buffer, count, ppos,
861                         create_trace_kprobe);
862 }
863 
864 static const struct file_operations kprobe_events_ops = {
865         .owner          = THIS_MODULE,
866         .open           = probes_open,
867         .read           = seq_read,
868         .llseek         = seq_lseek,
869         .release        = seq_release,
870         .write          = probes_write,
871 };
872 
873 /* Probes profiling interfaces */
874 static int probes_profile_seq_show(struct seq_file *m, void *v)
875 {
876         struct trace_kprobe *tk = v;
877 
878         seq_printf(m, "  %-44s %15lu %15lu\n",
879                    trace_event_name(&tk->tp.call), tk->nhit,
880                    tk->rp.kp.nmissed);
881 
882         return 0;
883 }
884 
885 static const struct seq_operations profile_seq_op = {
886         .start  = probes_seq_start,
887         .next   = probes_seq_next,
888         .stop   = probes_seq_stop,
889         .show   = probes_profile_seq_show
890 };
891 
892 static int profile_open(struct inode *inode, struct file *file)
893 {
894         return seq_open(file, &profile_seq_op);
895 }
896 
897 static const struct file_operations kprobe_profile_ops = {
898         .owner          = THIS_MODULE,
899         .open           = profile_open,
900         .read           = seq_read,
901         .llseek         = seq_lseek,
902         .release        = seq_release,
903 };
904 
905 /* Kprobe handler */
906 static nokprobe_inline void
907 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
908                     struct trace_event_file *trace_file)
909 {
910         struct kprobe_trace_entry_head *entry;
911         struct ring_buffer_event *event;
912         struct ring_buffer *buffer;
913         int size, dsize, pc;
914         unsigned long irq_flags;
915         struct trace_event_call *call = &tk->tp.call;
916 
917         WARN_ON(call != trace_file->event_call);
918 
919         if (trace_trigger_soft_disabled(trace_file))
920                 return;
921 
922         local_save_flags(irq_flags);
923         pc = preempt_count();
924 
925         dsize = __get_data_size(&tk->tp, regs);
926         size = sizeof(*entry) + tk->tp.size + dsize;
927 
928         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
929                                                 call->event.type,
930                                                 size, irq_flags, pc);
931         if (!event)
932                 return;
933 
934         entry = ring_buffer_event_data(event);
935         entry->ip = (unsigned long)tk->rp.kp.addr;
936         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
937 
938         event_trigger_unlock_commit_regs(trace_file, buffer, event,
939                                          entry, irq_flags, pc, regs);
940 }
941 
942 static void
943 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
944 {
945         struct event_file_link *link;
946 
947         list_for_each_entry_rcu(link, &tk->tp.files, list)
948                 __kprobe_trace_func(tk, regs, link->file);
949 }
950 NOKPROBE_SYMBOL(kprobe_trace_func);
951 
952 /* Kretprobe handler */
953 static nokprobe_inline void
954 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
955                        struct pt_regs *regs,
956                        struct trace_event_file *trace_file)
957 {
958         struct kretprobe_trace_entry_head *entry;
959         struct ring_buffer_event *event;
960         struct ring_buffer *buffer;
961         int size, pc, dsize;
962         unsigned long irq_flags;
963         struct trace_event_call *call = &tk->tp.call;
964 
965         WARN_ON(call != trace_file->event_call);
966 
967         if (trace_trigger_soft_disabled(trace_file))
968                 return;
969 
970         local_save_flags(irq_flags);
971         pc = preempt_count();
972 
973         dsize = __get_data_size(&tk->tp, regs);
974         size = sizeof(*entry) + tk->tp.size + dsize;
975 
976         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
977                                                 call->event.type,
978                                                 size, irq_flags, pc);
979         if (!event)
980                 return;
981 
982         entry = ring_buffer_event_data(event);
983         entry->func = (unsigned long)tk->rp.kp.addr;
984         entry->ret_ip = (unsigned long)ri->ret_addr;
985         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
986 
987         event_trigger_unlock_commit_regs(trace_file, buffer, event,
988                                          entry, irq_flags, pc, regs);
989 }
990 
991 static void
992 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
993                      struct pt_regs *regs)
994 {
995         struct event_file_link *link;
996 
997         list_for_each_entry_rcu(link, &tk->tp.files, list)
998                 __kretprobe_trace_func(tk, ri, regs, link->file);
999 }
1000 NOKPROBE_SYMBOL(kretprobe_trace_func);
1001 
1002 /* Event entry printers */
1003 static enum print_line_t
1004 print_kprobe_event(struct trace_iterator *iter, int flags,
1005                    struct trace_event *event)
1006 {
1007         struct kprobe_trace_entry_head *field;
1008         struct trace_seq *s = &iter->seq;
1009         struct trace_probe *tp;
1010         u8 *data;
1011         int i;
1012 
1013         field = (struct kprobe_trace_entry_head *)iter->ent;
1014         tp = container_of(event, struct trace_probe, call.event);
1015 
1016         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1017 
1018         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1019                 goto out;
1020 
1021         trace_seq_putc(s, ')');
1022 
1023         data = (u8 *)&field[1];
1024         for (i = 0; i < tp->nr_args; i++)
1025                 if (!tp->args[i].type->print(s, tp->args[i].name,
1026                                              data + tp->args[i].offset, field))
1027                         goto out;
1028 
1029         trace_seq_putc(s, '\n');
1030  out:
1031         return trace_handle_return(s);
1032 }
1033 
1034 static enum print_line_t
1035 print_kretprobe_event(struct trace_iterator *iter, int flags,
1036                       struct trace_event *event)
1037 {
1038         struct kretprobe_trace_entry_head *field;
1039         struct trace_seq *s = &iter->seq;
1040         struct trace_probe *tp;
1041         u8 *data;
1042         int i;
1043 
1044         field = (struct kretprobe_trace_entry_head *)iter->ent;
1045         tp = container_of(event, struct trace_probe, call.event);
1046 
1047         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1048 
1049         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1050                 goto out;
1051 
1052         trace_seq_puts(s, " <- ");
1053 
1054         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1055                 goto out;
1056 
1057         trace_seq_putc(s, ')');
1058 
1059         data = (u8 *)&field[1];
1060         for (i = 0; i < tp->nr_args; i++)
1061                 if (!tp->args[i].type->print(s, tp->args[i].name,
1062                                              data + tp->args[i].offset, field))
1063                         goto out;
1064 
1065         trace_seq_putc(s, '\n');
1066 
1067  out:
1068         return trace_handle_return(s);
1069 }
1070 
1071 
1072 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1073 {
1074         int ret, i;
1075         struct kprobe_trace_entry_head field;
1076         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1077 
1078         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1079         /* Set argument names as fields */
1080         for (i = 0; i < tk->tp.nr_args; i++) {
1081                 struct probe_arg *parg = &tk->tp.args[i];
1082 
1083                 ret = trace_define_field(event_call, parg->type->fmttype,
1084                                          parg->name,
1085                                          sizeof(field) + parg->offset,
1086                                          parg->type->size,
1087                                          parg->type->is_signed,
1088                                          FILTER_OTHER);
1089                 if (ret)
1090                         return ret;
1091         }
1092         return 0;
1093 }
1094 
1095 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1096 {
1097         int ret, i;
1098         struct kretprobe_trace_entry_head field;
1099         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1100 
1101         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1102         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1103         /* Set argument names as fields */
1104         for (i = 0; i < tk->tp.nr_args; i++) {
1105                 struct probe_arg *parg = &tk->tp.args[i];
1106 
1107                 ret = trace_define_field(event_call, parg->type->fmttype,
1108                                          parg->name,
1109                                          sizeof(field) + parg->offset,
1110                                          parg->type->size,
1111                                          parg->type->is_signed,
1112                                          FILTER_OTHER);
1113                 if (ret)
1114                         return ret;
1115         }
1116         return 0;
1117 }
1118 
1119 #ifdef CONFIG_PERF_EVENTS
1120 
1121 /* Kprobe profile handler */
1122 static void
1123 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1124 {
1125         struct trace_event_call *call = &tk->tp.call;
1126         struct bpf_prog *prog = call->prog;
1127         struct kprobe_trace_entry_head *entry;
1128         struct hlist_head *head;
1129         int size, __size, dsize;
1130         int rctx;
1131 
1132         if (prog && !trace_call_bpf(prog, regs))
1133                 return;
1134 
1135         head = this_cpu_ptr(call->perf_events);
1136         if (hlist_empty(head))
1137                 return;
1138 
1139         dsize = __get_data_size(&tk->tp, regs);
1140         __size = sizeof(*entry) + tk->tp.size + dsize;
1141         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1142         size -= sizeof(u32);
1143 
1144         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1145         if (!entry)
1146                 return;
1147 
1148         entry->ip = (unsigned long)tk->rp.kp.addr;
1149         memset(&entry[1], 0, dsize);
1150         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1151         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1152 }
1153 NOKPROBE_SYMBOL(kprobe_perf_func);
1154 
1155 /* Kretprobe profile handler */
1156 static void
1157 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1158                     struct pt_regs *regs)
1159 {
1160         struct trace_event_call *call = &tk->tp.call;
1161         struct bpf_prog *prog = call->prog;
1162         struct kretprobe_trace_entry_head *entry;
1163         struct hlist_head *head;
1164         int size, __size, dsize;
1165         int rctx;
1166 
1167         if (prog && !trace_call_bpf(prog, regs))
1168                 return;
1169 
1170         head = this_cpu_ptr(call->perf_events);
1171         if (hlist_empty(head))
1172                 return;
1173 
1174         dsize = __get_data_size(&tk->tp, regs);
1175         __size = sizeof(*entry) + tk->tp.size + dsize;
1176         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1177         size -= sizeof(u32);
1178 
1179         entry = perf_trace_buf_prepare(size, call->event.type, NULL, &rctx);
1180         if (!entry)
1181                 return;
1182 
1183         entry->func = (unsigned long)tk->rp.kp.addr;
1184         entry->ret_ip = (unsigned long)ri->ret_addr;
1185         store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1186         perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
1187 }
1188 NOKPROBE_SYMBOL(kretprobe_perf_func);
1189 #endif  /* CONFIG_PERF_EVENTS */
1190 
1191 /*
1192  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1193  *
1194  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1195  * lockless, but we can't race with this __init function.
1196  */
1197 static int kprobe_register(struct trace_event_call *event,
1198                            enum trace_reg type, void *data)
1199 {
1200         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1201         struct trace_event_file *file = data;
1202 
1203         switch (type) {
1204         case TRACE_REG_REGISTER:
1205                 return enable_trace_kprobe(tk, file);
1206         case TRACE_REG_UNREGISTER:
1207                 return disable_trace_kprobe(tk, file);
1208 
1209 #ifdef CONFIG_PERF_EVENTS
1210         case TRACE_REG_PERF_REGISTER:
1211                 return enable_trace_kprobe(tk, NULL);
1212         case TRACE_REG_PERF_UNREGISTER:
1213                 return disable_trace_kprobe(tk, NULL);
1214         case TRACE_REG_PERF_OPEN:
1215         case TRACE_REG_PERF_CLOSE:
1216         case TRACE_REG_PERF_ADD:
1217         case TRACE_REG_PERF_DEL:
1218                 return 0;
1219 #endif
1220         }
1221         return 0;
1222 }
1223 
1224 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1225 {
1226         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1227 
1228         tk->nhit++;
1229 
1230         if (tk->tp.flags & TP_FLAG_TRACE)
1231                 kprobe_trace_func(tk, regs);
1232 #ifdef CONFIG_PERF_EVENTS
1233         if (tk->tp.flags & TP_FLAG_PROFILE)
1234                 kprobe_perf_func(tk, regs);
1235 #endif
1236         return 0;       /* We don't tweek kernel, so just return 0 */
1237 }
1238 NOKPROBE_SYMBOL(kprobe_dispatcher);
1239 
1240 static int
1241 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1242 {
1243         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1244 
1245         tk->nhit++;
1246 
1247         if (tk->tp.flags & TP_FLAG_TRACE)
1248                 kretprobe_trace_func(tk, ri, regs);
1249 #ifdef CONFIG_PERF_EVENTS
1250         if (tk->tp.flags & TP_FLAG_PROFILE)
1251                 kretprobe_perf_func(tk, ri, regs);
1252 #endif
1253         return 0;       /* We don't tweek kernel, so just return 0 */
1254 }
1255 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1256 
1257 static struct trace_event_functions kretprobe_funcs = {
1258         .trace          = print_kretprobe_event
1259 };
1260 
1261 static struct trace_event_functions kprobe_funcs = {
1262         .trace          = print_kprobe_event
1263 };
1264 
1265 static int register_kprobe_event(struct trace_kprobe *tk)
1266 {
1267         struct trace_event_call *call = &tk->tp.call;
1268         int ret;
1269 
1270         /* Initialize trace_event_call */
1271         INIT_LIST_HEAD(&call->class->fields);
1272         if (trace_kprobe_is_return(tk)) {
1273                 call->event.funcs = &kretprobe_funcs;
1274                 call->class->define_fields = kretprobe_event_define_fields;
1275         } else {
1276                 call->event.funcs = &kprobe_funcs;
1277                 call->class->define_fields = kprobe_event_define_fields;
1278         }
1279         if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1280                 return -ENOMEM;
1281         ret = register_trace_event(&call->event);
1282         if (!ret) {
1283                 kfree(call->print_fmt);
1284                 return -ENODEV;
1285         }
1286         call->flags = TRACE_EVENT_FL_KPROBE;
1287         call->class->reg = kprobe_register;
1288         call->data = tk;
1289         ret = trace_add_event_call(call);
1290         if (ret) {
1291                 pr_info("Failed to register kprobe event: %s\n",
1292                         trace_event_name(call));
1293                 kfree(call->print_fmt);
1294                 unregister_trace_event(&call->event);
1295         }
1296         return ret;
1297 }
1298 
1299 static int unregister_kprobe_event(struct trace_kprobe *tk)
1300 {
1301         int ret;
1302 
1303         /* tp->event is unregistered in trace_remove_event_call() */
1304         ret = trace_remove_event_call(&tk->tp.call);
1305         if (!ret)
1306                 kfree(tk->tp.call.print_fmt);
1307         return ret;
1308 }
1309 
1310 /* Make a tracefs interface for controlling probe points */
1311 static __init int init_kprobe_trace(void)
1312 {
1313         struct dentry *d_tracer;
1314         struct dentry *entry;
1315 
1316         if (register_module_notifier(&trace_kprobe_module_nb))
1317                 return -EINVAL;
1318 
1319         d_tracer = tracing_init_dentry();
1320         if (IS_ERR(d_tracer))
1321                 return 0;
1322 
1323         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1324                                     NULL, &kprobe_events_ops);
1325 
1326         /* Event list interface */
1327         if (!entry)
1328                 pr_warning("Could not create tracefs "
1329                            "'kprobe_events' entry\n");
1330 
1331         /* Profile interface */
1332         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1333                                     NULL, &kprobe_profile_ops);
1334 
1335         if (!entry)
1336                 pr_warning("Could not create tracefs "
1337                            "'kprobe_profile' entry\n");
1338         return 0;
1339 }
1340 fs_initcall(init_kprobe_trace);
1341 
1342 
1343 #ifdef CONFIG_FTRACE_STARTUP_TEST
1344 
1345 /*
1346  * The "__used" keeps gcc from removing the function symbol
1347  * from the kallsyms table.
1348  */
1349 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1350                                                int a4, int a5, int a6)
1351 {
1352         return a1 + a2 + a3 + a4 + a5 + a6;
1353 }
1354 
1355 static struct trace_event_file *
1356 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1357 {
1358         struct trace_event_file *file;
1359 
1360         list_for_each_entry(file, &tr->events, list)
1361                 if (file->event_call == &tk->tp.call)
1362                         return file;
1363 
1364         return NULL;
1365 }
1366 
1367 /*
1368  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1369  * stage, we can do this lockless.
1370  */
1371 static __init int kprobe_trace_self_tests_init(void)
1372 {
1373         int ret, warn = 0;
1374         int (*target)(int, int, int, int, int, int);
1375         struct trace_kprobe *tk;
1376         struct trace_event_file *file;
1377 
1378         if (tracing_is_disabled())
1379                 return -ENODEV;
1380 
1381         target = kprobe_trace_selftest_target;
1382 
1383         pr_info("Testing kprobe tracing: ");
1384 
1385         ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target "
1386                                   "$stack $stack0 +0($stack)",
1387                                   create_trace_kprobe);
1388         if (WARN_ON_ONCE(ret)) {
1389                 pr_warn("error on probing function entry.\n");
1390                 warn++;
1391         } else {
1392                 /* Enable trace point */
1393                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1394                 if (WARN_ON_ONCE(tk == NULL)) {
1395                         pr_warn("error on getting new probe.\n");
1396                         warn++;
1397                 } else {
1398                         file = find_trace_probe_file(tk, top_trace_array());
1399                         if (WARN_ON_ONCE(file == NULL)) {
1400                                 pr_warn("error on getting probe file.\n");
1401                                 warn++;
1402                         } else
1403                                 enable_trace_kprobe(tk, file);
1404                 }
1405         }
1406 
1407         ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
1408                                   "$retval", create_trace_kprobe);
1409         if (WARN_ON_ONCE(ret)) {
1410                 pr_warn("error on probing function return.\n");
1411                 warn++;
1412         } else {
1413                 /* Enable trace point */
1414                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1415                 if (WARN_ON_ONCE(tk == NULL)) {
1416                         pr_warn("error on getting 2nd new probe.\n");
1417                         warn++;
1418                 } else {
1419                         file = find_trace_probe_file(tk, top_trace_array());
1420                         if (WARN_ON_ONCE(file == NULL)) {
1421                                 pr_warn("error on getting probe file.\n");
1422                                 warn++;
1423                         } else
1424                                 enable_trace_kprobe(tk, file);
1425                 }
1426         }
1427 
1428         if (warn)
1429                 goto end;
1430 
1431         ret = target(1, 2, 3, 4, 5, 6);
1432 
1433         /* Disable trace points before removing it */
1434         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1435         if (WARN_ON_ONCE(tk == NULL)) {
1436                 pr_warn("error on getting test probe.\n");
1437                 warn++;
1438         } else {
1439                 file = find_trace_probe_file(tk, top_trace_array());
1440                 if (WARN_ON_ONCE(file == NULL)) {
1441                         pr_warn("error on getting probe file.\n");
1442                         warn++;
1443                 } else
1444                         disable_trace_kprobe(tk, file);
1445         }
1446 
1447         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1448         if (WARN_ON_ONCE(tk == NULL)) {
1449                 pr_warn("error on getting 2nd test probe.\n");
1450                 warn++;
1451         } else {
1452                 file = find_trace_probe_file(tk, top_trace_array());
1453                 if (WARN_ON_ONCE(file == NULL)) {
1454                         pr_warn("error on getting probe file.\n");
1455                         warn++;
1456                 } else
1457                         disable_trace_kprobe(tk, file);
1458         }
1459 
1460         ret = traceprobe_command("-:testprobe", create_trace_kprobe);
1461         if (WARN_ON_ONCE(ret)) {
1462                 pr_warn("error on deleting a probe.\n");
1463                 warn++;
1464         }
1465 
1466         ret = traceprobe_command("-:testprobe2", create_trace_kprobe);
1467         if (WARN_ON_ONCE(ret)) {
1468                 pr_warn("error on deleting a probe.\n");
1469                 warn++;
1470         }
1471 
1472 end:
1473         release_all_trace_kprobes();
1474         if (warn)
1475                 pr_cont("NG: Some tests are failed. Please check them.\n");
1476         else
1477                 pr_cont("OK\n");
1478         return 0;
1479 }
1480 
1481 late_initcall(kprobe_trace_self_tests_init);
1482 
1483 #endif
1484 

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