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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_uprobe.c

Version: ~ [ linux-4.17-rc1 ] ~ [ linux-4.16.2 ] ~ [ linux-4.15.17 ] ~ [ linux-4.14.34 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.94 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.128 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.51 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.105 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.56 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.101 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * uprobes-based tracing events
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 as
  6  * published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  * GNU General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public License
 14  * along with this program; if not, write to the Free Software
 15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 16  *
 17  * Copyright (C) IBM Corporation, 2010-2012
 18  * Author:      Srikar Dronamraju <srikar@linux.vnet.ibm.com>
 19  */
 20 #define pr_fmt(fmt)     "trace_kprobe: " fmt
 21 
 22 #include <linux/module.h>
 23 #include <linux/uaccess.h>
 24 #include <linux/uprobes.h>
 25 #include <linux/namei.h>
 26 #include <linux/string.h>
 27 #include <linux/rculist.h>
 28 
 29 #include "trace_probe.h"
 30 
 31 #define UPROBE_EVENT_SYSTEM     "uprobes"
 32 
 33 struct uprobe_trace_entry_head {
 34         struct trace_entry      ent;
 35         unsigned long           vaddr[];
 36 };
 37 
 38 #define SIZEOF_TRACE_ENTRY(is_return)                   \
 39         (sizeof(struct uprobe_trace_entry_head) +       \
 40          sizeof(unsigned long) * (is_return ? 2 : 1))
 41 
 42 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
 43         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
 44 
 45 struct trace_uprobe_filter {
 46         rwlock_t                rwlock;
 47         int                     nr_systemwide;
 48         struct list_head        perf_events;
 49 };
 50 
 51 /*
 52  * uprobe event core functions
 53  */
 54 struct trace_uprobe {
 55         struct list_head                list;
 56         struct trace_uprobe_filter      filter;
 57         struct uprobe_consumer          consumer;
 58         struct inode                    *inode;
 59         char                            *filename;
 60         unsigned long                   offset;
 61         unsigned long                   nhit;
 62         struct trace_probe              tp;
 63 };
 64 
 65 #define SIZEOF_TRACE_UPROBE(n)                          \
 66         (offsetof(struct trace_uprobe, tp.args) +       \
 67         (sizeof(struct probe_arg) * (n)))
 68 
 69 static int register_uprobe_event(struct trace_uprobe *tu);
 70 static int unregister_uprobe_event(struct trace_uprobe *tu);
 71 
 72 static DEFINE_MUTEX(uprobe_lock);
 73 static LIST_HEAD(uprobe_list);
 74 
 75 struct uprobe_dispatch_data {
 76         struct trace_uprobe     *tu;
 77         unsigned long           bp_addr;
 78 };
 79 
 80 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
 81 static int uretprobe_dispatcher(struct uprobe_consumer *con,
 82                                 unsigned long func, struct pt_regs *regs);
 83 
 84 #ifdef CONFIG_STACK_GROWSUP
 85 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 86 {
 87         return addr - (n * sizeof(long));
 88 }
 89 #else
 90 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 91 {
 92         return addr + (n * sizeof(long));
 93 }
 94 #endif
 95 
 96 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
 97 {
 98         unsigned long ret;
 99         unsigned long addr = user_stack_pointer(regs);
100 
101         addr = adjust_stack_addr(addr, n);
102 
103         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
104                 return 0;
105 
106         return ret;
107 }
108 
109 /*
110  * Uprobes-specific fetch functions
111  */
112 #define DEFINE_FETCH_stack(type)                                        \
113 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,          \
114                                          void *offset, void *dest)      \
115 {                                                                       \
116         *(type *)dest = (type)get_user_stack_nth(regs,                  \
117                                               ((unsigned long)offset)); \
118 }
119 DEFINE_BASIC_FETCH_FUNCS(stack)
120 /* No string on the stack entry */
121 #define fetch_stack_string      NULL
122 #define fetch_stack_string_size NULL
123 
124 #define DEFINE_FETCH_memory(type)                                       \
125 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,         \
126                                           void *addr, void *dest)       \
127 {                                                                       \
128         type retval;                                                    \
129         void __user *vaddr = (void __force __user *) addr;              \
130                                                                         \
131         if (copy_from_user(&retval, vaddr, sizeof(type)))               \
132                 *(type *)dest = 0;                                      \
133         else                                                            \
134                 *(type *) dest = retval;                                \
135 }
136 DEFINE_BASIC_FETCH_FUNCS(memory)
137 /*
138  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
139  * length and relative data location.
140  */
141 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
142                                             void *addr, void *dest)
143 {
144         long ret;
145         u32 rloc = *(u32 *)dest;
146         int maxlen  = get_rloc_len(rloc);
147         u8 *dst = get_rloc_data(dest);
148         void __user *src = (void __force __user *) addr;
149 
150         if (!maxlen)
151                 return;
152 
153         ret = strncpy_from_user(dst, src, maxlen);
154         if (ret == maxlen)
155                 dst[--ret] = '\0';
156 
157         if (ret < 0) {  /* Failed to fetch string */
158                 ((u8 *)get_rloc_data(dest))[0] = '\0';
159                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
160         } else {
161                 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
162         }
163 }
164 
165 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
166                                                  void *addr, void *dest)
167 {
168         int len;
169         void __user *vaddr = (void __force __user *) addr;
170 
171         len = strnlen_user(vaddr, MAX_STRING_SIZE);
172 
173         if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
174                 *(u32 *)dest = 0;
175         else
176                 *(u32 *)dest = len;
177 }
178 
179 static unsigned long translate_user_vaddr(void *file_offset)
180 {
181         unsigned long base_addr;
182         struct uprobe_dispatch_data *udd;
183 
184         udd = (void *) current->utask->vaddr;
185 
186         base_addr = udd->bp_addr - udd->tu->offset;
187         return base_addr + (unsigned long)file_offset;
188 }
189 
190 #define DEFINE_FETCH_file_offset(type)                                  \
191 static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,    \
192                                                void *offset, void *dest)\
193 {                                                                       \
194         void *vaddr = (void *)translate_user_vaddr(offset);             \
195                                                                         \
196         FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);               \
197 }
198 DEFINE_BASIC_FETCH_FUNCS(file_offset)
199 DEFINE_FETCH_file_offset(string)
200 DEFINE_FETCH_file_offset(string_size)
201 
202 /* Fetch type information table */
203 static const struct fetch_type uprobes_fetch_type_table[] = {
204         /* Special types */
205         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
206                                         sizeof(u32), 1, "__data_loc char[]"),
207         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
208                                         string_size, sizeof(u32), 0, "u32"),
209         /* Basic types */
210         ASSIGN_FETCH_TYPE(u8,  u8,  0),
211         ASSIGN_FETCH_TYPE(u16, u16, 0),
212         ASSIGN_FETCH_TYPE(u32, u32, 0),
213         ASSIGN_FETCH_TYPE(u64, u64, 0),
214         ASSIGN_FETCH_TYPE(s8,  u8,  1),
215         ASSIGN_FETCH_TYPE(s16, u16, 1),
216         ASSIGN_FETCH_TYPE(s32, u32, 1),
217         ASSIGN_FETCH_TYPE(s64, u64, 1),
218         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
219         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
220         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
221         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
222 
223         ASSIGN_FETCH_TYPE_END
224 };
225 
226 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
227 {
228         rwlock_init(&filter->rwlock);
229         filter->nr_systemwide = 0;
230         INIT_LIST_HEAD(&filter->perf_events);
231 }
232 
233 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
234 {
235         return !filter->nr_systemwide && list_empty(&filter->perf_events);
236 }
237 
238 static inline bool is_ret_probe(struct trace_uprobe *tu)
239 {
240         return tu->consumer.ret_handler != NULL;
241 }
242 
243 /*
244  * Allocate new trace_uprobe and initialize it (including uprobes).
245  */
246 static struct trace_uprobe *
247 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
248 {
249         struct trace_uprobe *tu;
250 
251         if (!event || !is_good_name(event))
252                 return ERR_PTR(-EINVAL);
253 
254         if (!group || !is_good_name(group))
255                 return ERR_PTR(-EINVAL);
256 
257         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
258         if (!tu)
259                 return ERR_PTR(-ENOMEM);
260 
261         tu->tp.call.class = &tu->tp.class;
262         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
263         if (!tu->tp.call.name)
264                 goto error;
265 
266         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
267         if (!tu->tp.class.system)
268                 goto error;
269 
270         INIT_LIST_HEAD(&tu->list);
271         INIT_LIST_HEAD(&tu->tp.files);
272         tu->consumer.handler = uprobe_dispatcher;
273         if (is_ret)
274                 tu->consumer.ret_handler = uretprobe_dispatcher;
275         init_trace_uprobe_filter(&tu->filter);
276         return tu;
277 
278 error:
279         kfree(tu->tp.call.name);
280         kfree(tu);
281 
282         return ERR_PTR(-ENOMEM);
283 }
284 
285 static void free_trace_uprobe(struct trace_uprobe *tu)
286 {
287         int i;
288 
289         for (i = 0; i < tu->tp.nr_args; i++)
290                 traceprobe_free_probe_arg(&tu->tp.args[i]);
291 
292         iput(tu->inode);
293         kfree(tu->tp.call.class->system);
294         kfree(tu->tp.call.name);
295         kfree(tu->filename);
296         kfree(tu);
297 }
298 
299 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
300 {
301         struct trace_uprobe *tu;
302 
303         list_for_each_entry(tu, &uprobe_list, list)
304                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
305                     strcmp(tu->tp.call.class->system, group) == 0)
306                         return tu;
307 
308         return NULL;
309 }
310 
311 /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
312 static int unregister_trace_uprobe(struct trace_uprobe *tu)
313 {
314         int ret;
315 
316         ret = unregister_uprobe_event(tu);
317         if (ret)
318                 return ret;
319 
320         list_del(&tu->list);
321         free_trace_uprobe(tu);
322         return 0;
323 }
324 
325 /* Register a trace_uprobe and probe_event */
326 static int register_trace_uprobe(struct trace_uprobe *tu)
327 {
328         struct trace_uprobe *old_tu;
329         int ret;
330 
331         mutex_lock(&uprobe_lock);
332 
333         /* register as an event */
334         old_tu = find_probe_event(trace_event_name(&tu->tp.call),
335                         tu->tp.call.class->system);
336         if (old_tu) {
337                 /* delete old event */
338                 ret = unregister_trace_uprobe(old_tu);
339                 if (ret)
340                         goto end;
341         }
342 
343         ret = register_uprobe_event(tu);
344         if (ret) {
345                 pr_warn("Failed to register probe event(%d)\n", ret);
346                 goto end;
347         }
348 
349         list_add_tail(&tu->list, &uprobe_list);
350 
351 end:
352         mutex_unlock(&uprobe_lock);
353 
354         return ret;
355 }
356 
357 /*
358  * Argument syntax:
359  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
360  *
361  *  - Remove uprobe: -:[GRP/]EVENT
362  */
363 static int create_trace_uprobe(int argc, char **argv)
364 {
365         struct trace_uprobe *tu;
366         struct inode *inode;
367         char *arg, *event, *group, *filename;
368         char buf[MAX_EVENT_NAME_LEN];
369         struct path path;
370         unsigned long offset;
371         bool is_delete, is_return;
372         int i, ret;
373 
374         inode = NULL;
375         ret = 0;
376         is_delete = false;
377         is_return = false;
378         event = NULL;
379         group = NULL;
380 
381         /* argc must be >= 1 */
382         if (argv[0][0] == '-')
383                 is_delete = true;
384         else if (argv[0][0] == 'r')
385                 is_return = true;
386         else if (argv[0][0] != 'p') {
387                 pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
388                 return -EINVAL;
389         }
390 
391         if (argv[0][1] == ':') {
392                 event = &argv[0][2];
393                 arg = strchr(event, '/');
394 
395                 if (arg) {
396                         group = event;
397                         event = arg + 1;
398                         event[-1] = '\0';
399 
400                         if (strlen(group) == 0) {
401                                 pr_info("Group name is not specified\n");
402                                 return -EINVAL;
403                         }
404                 }
405                 if (strlen(event) == 0) {
406                         pr_info("Event name is not specified\n");
407                         return -EINVAL;
408                 }
409         }
410         if (!group)
411                 group = UPROBE_EVENT_SYSTEM;
412 
413         if (is_delete) {
414                 int ret;
415 
416                 if (!event) {
417                         pr_info("Delete command needs an event name.\n");
418                         return -EINVAL;
419                 }
420                 mutex_lock(&uprobe_lock);
421                 tu = find_probe_event(event, group);
422 
423                 if (!tu) {
424                         mutex_unlock(&uprobe_lock);
425                         pr_info("Event %s/%s doesn't exist.\n", group, event);
426                         return -ENOENT;
427                 }
428                 /* delete an event */
429                 ret = unregister_trace_uprobe(tu);
430                 mutex_unlock(&uprobe_lock);
431                 return ret;
432         }
433 
434         if (argc < 2) {
435                 pr_info("Probe point is not specified.\n");
436                 return -EINVAL;
437         }
438         /* Find the last occurrence, in case the path contains ':' too. */
439         arg = strrchr(argv[1], ':');
440         if (!arg) {
441                 ret = -EINVAL;
442                 goto fail_address_parse;
443         }
444 
445         *arg++ = '\0';
446         filename = argv[1];
447         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
448         if (ret)
449                 goto fail_address_parse;
450 
451         inode = igrab(d_real_inode(path.dentry));
452         path_put(&path);
453 
454         if (!inode || !S_ISREG(inode->i_mode)) {
455                 ret = -EINVAL;
456                 goto fail_address_parse;
457         }
458 
459         ret = kstrtoul(arg, 0, &offset);
460         if (ret)
461                 goto fail_address_parse;
462 
463         argc -= 2;
464         argv += 2;
465 
466         /* setup a probe */
467         if (!event) {
468                 char *tail;
469                 char *ptr;
470 
471                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
472                 if (!tail) {
473                         ret = -ENOMEM;
474                         goto fail_address_parse;
475                 }
476 
477                 ptr = strpbrk(tail, ".-_");
478                 if (ptr)
479                         *ptr = '\0';
480 
481                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
482                 event = buf;
483                 kfree(tail);
484         }
485 
486         tu = alloc_trace_uprobe(group, event, argc, is_return);
487         if (IS_ERR(tu)) {
488                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
489                 ret = PTR_ERR(tu);
490                 goto fail_address_parse;
491         }
492         tu->offset = offset;
493         tu->inode = inode;
494         tu->filename = kstrdup(filename, GFP_KERNEL);
495 
496         if (!tu->filename) {
497                 pr_info("Failed to allocate filename.\n");
498                 ret = -ENOMEM;
499                 goto error;
500         }
501 
502         /* parse arguments */
503         ret = 0;
504         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
505                 struct probe_arg *parg = &tu->tp.args[i];
506 
507                 /* Increment count for freeing args in error case */
508                 tu->tp.nr_args++;
509 
510                 /* Parse argument name */
511                 arg = strchr(argv[i], '=');
512                 if (arg) {
513                         *arg++ = '\0';
514                         parg->name = kstrdup(argv[i], GFP_KERNEL);
515                 } else {
516                         arg = argv[i];
517                         /* If argument name is omitted, set "argN" */
518                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
519                         parg->name = kstrdup(buf, GFP_KERNEL);
520                 }
521 
522                 if (!parg->name) {
523                         pr_info("Failed to allocate argument[%d] name.\n", i);
524                         ret = -ENOMEM;
525                         goto error;
526                 }
527 
528                 if (!is_good_name(parg->name)) {
529                         pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
530                         ret = -EINVAL;
531                         goto error;
532                 }
533 
534                 if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
535                         pr_info("Argument[%d] name '%s' conflicts with "
536                                 "another field.\n", i, argv[i]);
537                         ret = -EINVAL;
538                         goto error;
539                 }
540 
541                 /* Parse fetch argument */
542                 ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
543                                                  is_return, false,
544                                                  uprobes_fetch_type_table);
545                 if (ret) {
546                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
547                         goto error;
548                 }
549         }
550 
551         ret = register_trace_uprobe(tu);
552         if (ret)
553                 goto error;
554         return 0;
555 
556 error:
557         free_trace_uprobe(tu);
558         return ret;
559 
560 fail_address_parse:
561         iput(inode);
562 
563         pr_info("Failed to parse address or file.\n");
564 
565         return ret;
566 }
567 
568 static int cleanup_all_probes(void)
569 {
570         struct trace_uprobe *tu;
571         int ret = 0;
572 
573         mutex_lock(&uprobe_lock);
574         while (!list_empty(&uprobe_list)) {
575                 tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
576                 ret = unregister_trace_uprobe(tu);
577                 if (ret)
578                         break;
579         }
580         mutex_unlock(&uprobe_lock);
581         return ret;
582 }
583 
584 /* Probes listing interfaces */
585 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
586 {
587         mutex_lock(&uprobe_lock);
588         return seq_list_start(&uprobe_list, *pos);
589 }
590 
591 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
592 {
593         return seq_list_next(v, &uprobe_list, pos);
594 }
595 
596 static void probes_seq_stop(struct seq_file *m, void *v)
597 {
598         mutex_unlock(&uprobe_lock);
599 }
600 
601 static int probes_seq_show(struct seq_file *m, void *v)
602 {
603         struct trace_uprobe *tu = v;
604         char c = is_ret_probe(tu) ? 'r' : 'p';
605         int i;
606 
607         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
608                         trace_event_name(&tu->tp.call), tu->filename,
609                         (int)(sizeof(void *) * 2), tu->offset);
610 
611         for (i = 0; i < tu->tp.nr_args; i++)
612                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
613 
614         seq_putc(m, '\n');
615         return 0;
616 }
617 
618 static const struct seq_operations probes_seq_op = {
619         .start  = probes_seq_start,
620         .next   = probes_seq_next,
621         .stop   = probes_seq_stop,
622         .show   = probes_seq_show
623 };
624 
625 static int probes_open(struct inode *inode, struct file *file)
626 {
627         int ret;
628 
629         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
630                 ret = cleanup_all_probes();
631                 if (ret)
632                         return ret;
633         }
634 
635         return seq_open(file, &probes_seq_op);
636 }
637 
638 static ssize_t probes_write(struct file *file, const char __user *buffer,
639                             size_t count, loff_t *ppos)
640 {
641         return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
642 }
643 
644 static const struct file_operations uprobe_events_ops = {
645         .owner          = THIS_MODULE,
646         .open           = probes_open,
647         .read           = seq_read,
648         .llseek         = seq_lseek,
649         .release        = seq_release,
650         .write          = probes_write,
651 };
652 
653 /* Probes profiling interfaces */
654 static int probes_profile_seq_show(struct seq_file *m, void *v)
655 {
656         struct trace_uprobe *tu = v;
657 
658         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
659                         trace_event_name(&tu->tp.call), tu->nhit);
660         return 0;
661 }
662 
663 static const struct seq_operations profile_seq_op = {
664         .start  = probes_seq_start,
665         .next   = probes_seq_next,
666         .stop   = probes_seq_stop,
667         .show   = probes_profile_seq_show
668 };
669 
670 static int profile_open(struct inode *inode, struct file *file)
671 {
672         return seq_open(file, &profile_seq_op);
673 }
674 
675 static const struct file_operations uprobe_profile_ops = {
676         .owner          = THIS_MODULE,
677         .open           = profile_open,
678         .read           = seq_read,
679         .llseek         = seq_lseek,
680         .release        = seq_release,
681 };
682 
683 struct uprobe_cpu_buffer {
684         struct mutex mutex;
685         void *buf;
686 };
687 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
688 static int uprobe_buffer_refcnt;
689 
690 static int uprobe_buffer_init(void)
691 {
692         int cpu, err_cpu;
693 
694         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
695         if (uprobe_cpu_buffer == NULL)
696                 return -ENOMEM;
697 
698         for_each_possible_cpu(cpu) {
699                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
700                                                   GFP_KERNEL, 0);
701                 if (p == NULL) {
702                         err_cpu = cpu;
703                         goto err;
704                 }
705                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
706                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
707         }
708 
709         return 0;
710 
711 err:
712         for_each_possible_cpu(cpu) {
713                 if (cpu == err_cpu)
714                         break;
715                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
716         }
717 
718         free_percpu(uprobe_cpu_buffer);
719         return -ENOMEM;
720 }
721 
722 static int uprobe_buffer_enable(void)
723 {
724         int ret = 0;
725 
726         BUG_ON(!mutex_is_locked(&event_mutex));
727 
728         if (uprobe_buffer_refcnt++ == 0) {
729                 ret = uprobe_buffer_init();
730                 if (ret < 0)
731                         uprobe_buffer_refcnt--;
732         }
733 
734         return ret;
735 }
736 
737 static void uprobe_buffer_disable(void)
738 {
739         int cpu;
740 
741         BUG_ON(!mutex_is_locked(&event_mutex));
742 
743         if (--uprobe_buffer_refcnt == 0) {
744                 for_each_possible_cpu(cpu)
745                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
746                                                              cpu)->buf);
747 
748                 free_percpu(uprobe_cpu_buffer);
749                 uprobe_cpu_buffer = NULL;
750         }
751 }
752 
753 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
754 {
755         struct uprobe_cpu_buffer *ucb;
756         int cpu;
757 
758         cpu = raw_smp_processor_id();
759         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
760 
761         /*
762          * Use per-cpu buffers for fastest access, but we might migrate
763          * so the mutex makes sure we have sole access to it.
764          */
765         mutex_lock(&ucb->mutex);
766 
767         return ucb;
768 }
769 
770 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
771 {
772         mutex_unlock(&ucb->mutex);
773 }
774 
775 static void __uprobe_trace_func(struct trace_uprobe *tu,
776                                 unsigned long func, struct pt_regs *regs,
777                                 struct uprobe_cpu_buffer *ucb, int dsize,
778                                 struct trace_event_file *trace_file)
779 {
780         struct uprobe_trace_entry_head *entry;
781         struct ring_buffer_event *event;
782         struct ring_buffer *buffer;
783         void *data;
784         int size, esize;
785         struct trace_event_call *call = &tu->tp.call;
786 
787         WARN_ON(call != trace_file->event_call);
788 
789         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
790                 return;
791 
792         if (trace_trigger_soft_disabled(trace_file))
793                 return;
794 
795         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
796         size = esize + tu->tp.size + dsize;
797         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
798                                                 call->event.type, size, 0, 0);
799         if (!event)
800                 return;
801 
802         entry = ring_buffer_event_data(event);
803         if (is_ret_probe(tu)) {
804                 entry->vaddr[0] = func;
805                 entry->vaddr[1] = instruction_pointer(regs);
806                 data = DATAOF_TRACE_ENTRY(entry, true);
807         } else {
808                 entry->vaddr[0] = instruction_pointer(regs);
809                 data = DATAOF_TRACE_ENTRY(entry, false);
810         }
811 
812         memcpy(data, ucb->buf, tu->tp.size + dsize);
813 
814         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
815 }
816 
817 /* uprobe handler */
818 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
819                              struct uprobe_cpu_buffer *ucb, int dsize)
820 {
821         struct event_file_link *link;
822 
823         if (is_ret_probe(tu))
824                 return 0;
825 
826         rcu_read_lock();
827         list_for_each_entry_rcu(link, &tu->tp.files, list)
828                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
829         rcu_read_unlock();
830 
831         return 0;
832 }
833 
834 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
835                                  struct pt_regs *regs,
836                                  struct uprobe_cpu_buffer *ucb, int dsize)
837 {
838         struct event_file_link *link;
839 
840         rcu_read_lock();
841         list_for_each_entry_rcu(link, &tu->tp.files, list)
842                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
843         rcu_read_unlock();
844 }
845 
846 /* Event entry printers */
847 static enum print_line_t
848 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
849 {
850         struct uprobe_trace_entry_head *entry;
851         struct trace_seq *s = &iter->seq;
852         struct trace_uprobe *tu;
853         u8 *data;
854         int i;
855 
856         entry = (struct uprobe_trace_entry_head *)iter->ent;
857         tu = container_of(event, struct trace_uprobe, tp.call.event);
858 
859         if (is_ret_probe(tu)) {
860                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
861                                  trace_event_name(&tu->tp.call),
862                                  entry->vaddr[1], entry->vaddr[0]);
863                 data = DATAOF_TRACE_ENTRY(entry, true);
864         } else {
865                 trace_seq_printf(s, "%s: (0x%lx)",
866                                  trace_event_name(&tu->tp.call),
867                                  entry->vaddr[0]);
868                 data = DATAOF_TRACE_ENTRY(entry, false);
869         }
870 
871         for (i = 0; i < tu->tp.nr_args; i++) {
872                 struct probe_arg *parg = &tu->tp.args[i];
873 
874                 if (!parg->type->print(s, parg->name, data + parg->offset, entry))
875                         goto out;
876         }
877 
878         trace_seq_putc(s, '\n');
879 
880  out:
881         return trace_handle_return(s);
882 }
883 
884 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
885                                 enum uprobe_filter_ctx ctx,
886                                 struct mm_struct *mm);
887 
888 static int
889 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
890                    filter_func_t filter)
891 {
892         bool enabled = trace_probe_is_enabled(&tu->tp);
893         struct event_file_link *link = NULL;
894         int ret;
895 
896         if (file) {
897                 if (tu->tp.flags & TP_FLAG_PROFILE)
898                         return -EINTR;
899 
900                 link = kmalloc(sizeof(*link), GFP_KERNEL);
901                 if (!link)
902                         return -ENOMEM;
903 
904                 link->file = file;
905                 list_add_tail_rcu(&link->list, &tu->tp.files);
906 
907                 tu->tp.flags |= TP_FLAG_TRACE;
908         } else {
909                 if (tu->tp.flags & TP_FLAG_TRACE)
910                         return -EINTR;
911 
912                 tu->tp.flags |= TP_FLAG_PROFILE;
913         }
914 
915         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
916 
917         if (enabled)
918                 return 0;
919 
920         ret = uprobe_buffer_enable();
921         if (ret)
922                 goto err_flags;
923 
924         tu->consumer.filter = filter;
925         ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
926         if (ret)
927                 goto err_buffer;
928 
929         return 0;
930 
931  err_buffer:
932         uprobe_buffer_disable();
933 
934  err_flags:
935         if (file) {
936                 list_del(&link->list);
937                 kfree(link);
938                 tu->tp.flags &= ~TP_FLAG_TRACE;
939         } else {
940                 tu->tp.flags &= ~TP_FLAG_PROFILE;
941         }
942         return ret;
943 }
944 
945 static void
946 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
947 {
948         if (!trace_probe_is_enabled(&tu->tp))
949                 return;
950 
951         if (file) {
952                 struct event_file_link *link;
953 
954                 link = find_event_file_link(&tu->tp, file);
955                 if (!link)
956                         return;
957 
958                 list_del_rcu(&link->list);
959                 /* synchronize with u{,ret}probe_trace_func */
960                 synchronize_sched();
961                 kfree(link);
962 
963                 if (!list_empty(&tu->tp.files))
964                         return;
965         }
966 
967         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
968 
969         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
970         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
971 
972         uprobe_buffer_disable();
973 }
974 
975 static int uprobe_event_define_fields(struct trace_event_call *event_call)
976 {
977         int ret, i, size;
978         struct uprobe_trace_entry_head field;
979         struct trace_uprobe *tu = event_call->data;
980 
981         if (is_ret_probe(tu)) {
982                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
983                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
984                 size = SIZEOF_TRACE_ENTRY(true);
985         } else {
986                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
987                 size = SIZEOF_TRACE_ENTRY(false);
988         }
989         /* Set argument names as fields */
990         for (i = 0; i < tu->tp.nr_args; i++) {
991                 struct probe_arg *parg = &tu->tp.args[i];
992 
993                 ret = trace_define_field(event_call, parg->type->fmttype,
994                                          parg->name, size + parg->offset,
995                                          parg->type->size, parg->type->is_signed,
996                                          FILTER_OTHER);
997 
998                 if (ret)
999                         return ret;
1000         }
1001         return 0;
1002 }
1003 
1004 #ifdef CONFIG_PERF_EVENTS
1005 static bool
1006 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1007 {
1008         struct perf_event *event;
1009 
1010         if (filter->nr_systemwide)
1011                 return true;
1012 
1013         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1014                 if (event->hw.target->mm == mm)
1015                         return true;
1016         }
1017 
1018         return false;
1019 }
1020 
1021 static inline bool
1022 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1023 {
1024         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1025 }
1026 
1027 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1028 {
1029         bool done;
1030 
1031         write_lock(&tu->filter.rwlock);
1032         if (event->hw.target) {
1033                 list_del(&event->hw.tp_list);
1034                 done = tu->filter.nr_systemwide ||
1035                         (event->hw.target->flags & PF_EXITING) ||
1036                         uprobe_filter_event(tu, event);
1037         } else {
1038                 tu->filter.nr_systemwide--;
1039                 done = tu->filter.nr_systemwide;
1040         }
1041         write_unlock(&tu->filter.rwlock);
1042 
1043         if (!done)
1044                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1045 
1046         return 0;
1047 }
1048 
1049 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1050 {
1051         bool done;
1052         int err;
1053 
1054         write_lock(&tu->filter.rwlock);
1055         if (event->hw.target) {
1056                 /*
1057                  * event->parent != NULL means copy_process(), we can avoid
1058                  * uprobe_apply(). current->mm must be probed and we can rely
1059                  * on dup_mmap() which preserves the already installed bp's.
1060                  *
1061                  * attr.enable_on_exec means that exec/mmap will install the
1062                  * breakpoints we need.
1063                  */
1064                 done = tu->filter.nr_systemwide ||
1065                         event->parent || event->attr.enable_on_exec ||
1066                         uprobe_filter_event(tu, event);
1067                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1068         } else {
1069                 done = tu->filter.nr_systemwide;
1070                 tu->filter.nr_systemwide++;
1071         }
1072         write_unlock(&tu->filter.rwlock);
1073 
1074         err = 0;
1075         if (!done) {
1076                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1077                 if (err)
1078                         uprobe_perf_close(tu, event);
1079         }
1080         return err;
1081 }
1082 
1083 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1084                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1085 {
1086         struct trace_uprobe *tu;
1087         int ret;
1088 
1089         tu = container_of(uc, struct trace_uprobe, consumer);
1090         read_lock(&tu->filter.rwlock);
1091         ret = __uprobe_perf_filter(&tu->filter, mm);
1092         read_unlock(&tu->filter.rwlock);
1093 
1094         return ret;
1095 }
1096 
1097 static void __uprobe_perf_func(struct trace_uprobe *tu,
1098                                unsigned long func, struct pt_regs *regs,
1099                                struct uprobe_cpu_buffer *ucb, int dsize)
1100 {
1101         struct trace_event_call *call = &tu->tp.call;
1102         struct uprobe_trace_entry_head *entry;
1103         struct hlist_head *head;
1104         void *data;
1105         int size, esize;
1106         int rctx;
1107 
1108         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1109                 return;
1110 
1111         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1112 
1113         size = esize + tu->tp.size + dsize;
1114         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1115         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1116                 return;
1117 
1118         preempt_disable();
1119         head = this_cpu_ptr(call->perf_events);
1120         if (hlist_empty(head))
1121                 goto out;
1122 
1123         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1124         if (!entry)
1125                 goto out;
1126 
1127         if (is_ret_probe(tu)) {
1128                 entry->vaddr[0] = func;
1129                 entry->vaddr[1] = instruction_pointer(regs);
1130                 data = DATAOF_TRACE_ENTRY(entry, true);
1131         } else {
1132                 entry->vaddr[0] = instruction_pointer(regs);
1133                 data = DATAOF_TRACE_ENTRY(entry, false);
1134         }
1135 
1136         memcpy(data, ucb->buf, tu->tp.size + dsize);
1137 
1138         if (size - esize > tu->tp.size + dsize) {
1139                 int len = tu->tp.size + dsize;
1140 
1141                 memset(data + len, 0, size - esize - len);
1142         }
1143 
1144         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1145                               head, NULL);
1146  out:
1147         preempt_enable();
1148 }
1149 
1150 /* uprobe profile handler */
1151 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1152                             struct uprobe_cpu_buffer *ucb, int dsize)
1153 {
1154         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1155                 return UPROBE_HANDLER_REMOVE;
1156 
1157         if (!is_ret_probe(tu))
1158                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1159         return 0;
1160 }
1161 
1162 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1163                                 struct pt_regs *regs,
1164                                 struct uprobe_cpu_buffer *ucb, int dsize)
1165 {
1166         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1167 }
1168 #endif  /* CONFIG_PERF_EVENTS */
1169 
1170 static int
1171 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1172                       void *data)
1173 {
1174         struct trace_uprobe *tu = event->data;
1175         struct trace_event_file *file = data;
1176 
1177         switch (type) {
1178         case TRACE_REG_REGISTER:
1179                 return probe_event_enable(tu, file, NULL);
1180 
1181         case TRACE_REG_UNREGISTER:
1182                 probe_event_disable(tu, file);
1183                 return 0;
1184 
1185 #ifdef CONFIG_PERF_EVENTS
1186         case TRACE_REG_PERF_REGISTER:
1187                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1188 
1189         case TRACE_REG_PERF_UNREGISTER:
1190                 probe_event_disable(tu, NULL);
1191                 return 0;
1192 
1193         case TRACE_REG_PERF_OPEN:
1194                 return uprobe_perf_open(tu, data);
1195 
1196         case TRACE_REG_PERF_CLOSE:
1197                 return uprobe_perf_close(tu, data);
1198 
1199 #endif
1200         default:
1201                 return 0;
1202         }
1203         return 0;
1204 }
1205 
1206 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1207 {
1208         struct trace_uprobe *tu;
1209         struct uprobe_dispatch_data udd;
1210         struct uprobe_cpu_buffer *ucb;
1211         int dsize, esize;
1212         int ret = 0;
1213 
1214 
1215         tu = container_of(con, struct trace_uprobe, consumer);
1216         tu->nhit++;
1217 
1218         udd.tu = tu;
1219         udd.bp_addr = instruction_pointer(regs);
1220 
1221         current->utask->vaddr = (unsigned long) &udd;
1222 
1223         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1224                 return 0;
1225 
1226         dsize = __get_data_size(&tu->tp, regs);
1227         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1228 
1229         ucb = uprobe_buffer_get();
1230         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1231 
1232         if (tu->tp.flags & TP_FLAG_TRACE)
1233                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1234 
1235 #ifdef CONFIG_PERF_EVENTS
1236         if (tu->tp.flags & TP_FLAG_PROFILE)
1237                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1238 #endif
1239         uprobe_buffer_put(ucb);
1240         return ret;
1241 }
1242 
1243 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1244                                 unsigned long func, struct pt_regs *regs)
1245 {
1246         struct trace_uprobe *tu;
1247         struct uprobe_dispatch_data udd;
1248         struct uprobe_cpu_buffer *ucb;
1249         int dsize, esize;
1250 
1251         tu = container_of(con, struct trace_uprobe, consumer);
1252 
1253         udd.tu = tu;
1254         udd.bp_addr = func;
1255 
1256         current->utask->vaddr = (unsigned long) &udd;
1257 
1258         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1259                 return 0;
1260 
1261         dsize = __get_data_size(&tu->tp, regs);
1262         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1263 
1264         ucb = uprobe_buffer_get();
1265         store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
1266 
1267         if (tu->tp.flags & TP_FLAG_TRACE)
1268                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1269 
1270 #ifdef CONFIG_PERF_EVENTS
1271         if (tu->tp.flags & TP_FLAG_PROFILE)
1272                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1273 #endif
1274         uprobe_buffer_put(ucb);
1275         return 0;
1276 }
1277 
1278 static struct trace_event_functions uprobe_funcs = {
1279         .trace          = print_uprobe_event
1280 };
1281 
1282 static inline void init_trace_event_call(struct trace_uprobe *tu,
1283                                          struct trace_event_call *call)
1284 {
1285         INIT_LIST_HEAD(&call->class->fields);
1286         call->event.funcs = &uprobe_funcs;
1287         call->class->define_fields = uprobe_event_define_fields;
1288 
1289         call->flags = TRACE_EVENT_FL_UPROBE;
1290         call->class->reg = trace_uprobe_register;
1291         call->data = tu;
1292 }
1293 
1294 static int register_uprobe_event(struct trace_uprobe *tu)
1295 {
1296         struct trace_event_call *call = &tu->tp.call;
1297         int ret = 0;
1298 
1299         init_trace_event_call(tu, call);
1300 
1301         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1302                 return -ENOMEM;
1303 
1304         ret = register_trace_event(&call->event);
1305         if (!ret) {
1306                 kfree(call->print_fmt);
1307                 return -ENODEV;
1308         }
1309 
1310         ret = trace_add_event_call(call);
1311 
1312         if (ret) {
1313                 pr_info("Failed to register uprobe event: %s\n",
1314                         trace_event_name(call));
1315                 kfree(call->print_fmt);
1316                 unregister_trace_event(&call->event);
1317         }
1318 
1319         return ret;
1320 }
1321 
1322 static int unregister_uprobe_event(struct trace_uprobe *tu)
1323 {
1324         int ret;
1325 
1326         /* tu->event is unregistered in trace_remove_event_call() */
1327         ret = trace_remove_event_call(&tu->tp.call);
1328         if (ret)
1329                 return ret;
1330         kfree(tu->tp.call.print_fmt);
1331         tu->tp.call.print_fmt = NULL;
1332         return 0;
1333 }
1334 
1335 #ifdef CONFIG_PERF_EVENTS
1336 struct trace_event_call *
1337 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
1338 {
1339         struct trace_uprobe *tu;
1340         struct inode *inode;
1341         struct path path;
1342         int ret;
1343 
1344         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1345         if (ret)
1346                 return ERR_PTR(ret);
1347 
1348         inode = igrab(d_inode(path.dentry));
1349         path_put(&path);
1350 
1351         if (!inode || !S_ISREG(inode->i_mode)) {
1352                 iput(inode);
1353                 return ERR_PTR(-EINVAL);
1354         }
1355 
1356         /*
1357          * local trace_kprobes are not added to probe_list, so they are never
1358          * searched in find_trace_kprobe(). Therefore, there is no concern of
1359          * duplicated name "DUMMY_EVENT" here.
1360          */
1361         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1362                                 is_return);
1363 
1364         if (IS_ERR(tu)) {
1365                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1366                         (int)PTR_ERR(tu));
1367                 return ERR_CAST(tu);
1368         }
1369 
1370         tu->offset = offs;
1371         tu->inode = inode;
1372         tu->filename = kstrdup(name, GFP_KERNEL);
1373         init_trace_event_call(tu, &tu->tp.call);
1374 
1375         if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1376                 ret = -ENOMEM;
1377                 goto error;
1378         }
1379 
1380         return &tu->tp.call;
1381 error:
1382         free_trace_uprobe(tu);
1383         return ERR_PTR(ret);
1384 }
1385 
1386 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1387 {
1388         struct trace_uprobe *tu;
1389 
1390         tu = container_of(event_call, struct trace_uprobe, tp.call);
1391 
1392         kfree(tu->tp.call.print_fmt);
1393         tu->tp.call.print_fmt = NULL;
1394 
1395         free_trace_uprobe(tu);
1396 }
1397 #endif /* CONFIG_PERF_EVENTS */
1398 
1399 /* Make a trace interface for controling probe points */
1400 static __init int init_uprobe_trace(void)
1401 {
1402         struct dentry *d_tracer;
1403 
1404         d_tracer = tracing_init_dentry();
1405         if (IS_ERR(d_tracer))
1406                 return 0;
1407 
1408         trace_create_file("uprobe_events", 0644, d_tracer,
1409                                     NULL, &uprobe_events_ops);
1410         /* Profile interface */
1411         trace_create_file("uprobe_profile", 0444, d_tracer,
1412                                     NULL, &uprobe_profile_ops);
1413         return 0;
1414 }
1415 
1416 fs_initcall(init_uprobe_trace);
1417 

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