~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/kernel/kprobes.c

Version: ~ [ linux-5.8-rc5 ] ~ [ linux-5.7.8 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.51 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.132 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.188 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.230 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.230 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ 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-2.6.32.71 ] ~ [ 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  *  Kernel Probes (KProbes)
  3  *  kernel/kprobes.c
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU General Public License as published by
  7  * the Free Software Foundation; either version 2 of the License, or
  8  * (at your option) any later version.
  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  * Copyright (C) IBM Corporation, 2002, 2004
 20  *
 21  * 2002-Oct     Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
 22  *              Probes initial implementation (includes suggestions from
 23  *              Rusty Russell).
 24  * 2004-Aug     Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
 25  *              hlists and exceptions notifier as suggested by Andi Kleen.
 26  * 2004-July    Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
 27  *              interface to access function arguments.
 28  * 2004-Sep     Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
 29  *              exceptions notifier to be first on the priority list.
 30  * 2005-May     Hien Nguyen <hien@us.ibm.com>, Jim Keniston
 31  *              <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
 32  *              <prasanna@in.ibm.com> added function-return probes.
 33  */
 34 #include <linux/kprobes.h>
 35 #include <linux/hash.h>
 36 #include <linux/init.h>
 37 #include <linux/slab.h>
 38 #include <linux/stddef.h>
 39 #include <linux/export.h>
 40 #include <linux/moduleloader.h>
 41 #include <linux/kallsyms.h>
 42 #include <linux/freezer.h>
 43 #include <linux/seq_file.h>
 44 #include <linux/debugfs.h>
 45 #include <linux/sysctl.h>
 46 #include <linux/kdebug.h>
 47 #include <linux/memory.h>
 48 #include <linux/ftrace.h>
 49 #include <linux/cpu.h>
 50 #include <linux/jump_label.h>
 51 
 52 #include <asm/sections.h>
 53 #include <asm/cacheflush.h>
 54 #include <asm/errno.h>
 55 #include <linux/uaccess.h>
 56 
 57 #define KPROBE_HASH_BITS 6
 58 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
 59 
 60 
 61 static int kprobes_initialized;
 62 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 63 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 64 
 65 /* NOTE: change this value only with kprobe_mutex held */
 66 static bool kprobes_all_disarmed;
 67 
 68 /* This protects kprobe_table and optimizing_list */
 69 static DEFINE_MUTEX(kprobe_mutex);
 70 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 71 static struct {
 72         raw_spinlock_t lock ____cacheline_aligned_in_smp;
 73 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
 74 
 75 kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
 76                                         unsigned int __unused)
 77 {
 78         return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
 79 }
 80 
 81 static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
 82 {
 83         return &(kretprobe_table_locks[hash].lock);
 84 }
 85 
 86 /* Blacklist -- list of struct kprobe_blacklist_entry */
 87 static LIST_HEAD(kprobe_blacklist);
 88 
 89 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 90 /*
 91  * kprobe->ainsn.insn points to the copy of the instruction to be
 92  * single-stepped. x86_64, POWER4 and above have no-exec support and
 93  * stepping on the instruction on a vmalloced/kmalloced/data page
 94  * is a recipe for disaster
 95  */
 96 struct kprobe_insn_page {
 97         struct list_head list;
 98         kprobe_opcode_t *insns;         /* Page of instruction slots */
 99         struct kprobe_insn_cache *cache;
100         int nused;
101         int ngarbage;
102         char slot_used[];
103 };
104 
105 #define KPROBE_INSN_PAGE_SIZE(slots)                    \
106         (offsetof(struct kprobe_insn_page, slot_used) + \
107          (sizeof(char) * (slots)))
108 
109 static int slots_per_page(struct kprobe_insn_cache *c)
110 {
111         return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
112 }
113 
114 enum kprobe_slot_state {
115         SLOT_CLEAN = 0,
116         SLOT_DIRTY = 1,
117         SLOT_USED = 2,
118 };
119 
120 void __weak *alloc_insn_page(void)
121 {
122         return module_alloc(PAGE_SIZE);
123 }
124 
125 void __weak free_insn_page(void *page)
126 {
127         module_memfree(page);
128 }
129 
130 struct kprobe_insn_cache kprobe_insn_slots = {
131         .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
132         .alloc = alloc_insn_page,
133         .free = free_insn_page,
134         .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
135         .insn_size = MAX_INSN_SIZE,
136         .nr_garbage = 0,
137 };
138 static int collect_garbage_slots(struct kprobe_insn_cache *c);
139 
140 /**
141  * __get_insn_slot() - Find a slot on an executable page for an instruction.
142  * We allocate an executable page if there's no room on existing ones.
143  */
144 kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
145 {
146         struct kprobe_insn_page *kip;
147         kprobe_opcode_t *slot = NULL;
148 
149         /* Since the slot array is not protected by rcu, we need a mutex */
150         mutex_lock(&c->mutex);
151  retry:
152         rcu_read_lock();
153         list_for_each_entry_rcu(kip, &c->pages, list) {
154                 if (kip->nused < slots_per_page(c)) {
155                         int i;
156                         for (i = 0; i < slots_per_page(c); i++) {
157                                 if (kip->slot_used[i] == SLOT_CLEAN) {
158                                         kip->slot_used[i] = SLOT_USED;
159                                         kip->nused++;
160                                         slot = kip->insns + (i * c->insn_size);
161                                         rcu_read_unlock();
162                                         goto out;
163                                 }
164                         }
165                         /* kip->nused is broken. Fix it. */
166                         kip->nused = slots_per_page(c);
167                         WARN_ON(1);
168                 }
169         }
170         rcu_read_unlock();
171 
172         /* If there are any garbage slots, collect it and try again. */
173         if (c->nr_garbage && collect_garbage_slots(c) == 0)
174                 goto retry;
175 
176         /* All out of space.  Need to allocate a new page. */
177         kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
178         if (!kip)
179                 goto out;
180 
181         /*
182          * Use module_alloc so this page is within +/- 2GB of where the
183          * kernel image and loaded module images reside. This is required
184          * so x86_64 can correctly handle the %rip-relative fixups.
185          */
186         kip->insns = c->alloc();
187         if (!kip->insns) {
188                 kfree(kip);
189                 goto out;
190         }
191         INIT_LIST_HEAD(&kip->list);
192         memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
193         kip->slot_used[0] = SLOT_USED;
194         kip->nused = 1;
195         kip->ngarbage = 0;
196         kip->cache = c;
197         list_add_rcu(&kip->list, &c->pages);
198         slot = kip->insns;
199 out:
200         mutex_unlock(&c->mutex);
201         return slot;
202 }
203 
204 /* Return 1 if all garbages are collected, otherwise 0. */
205 static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
206 {
207         kip->slot_used[idx] = SLOT_CLEAN;
208         kip->nused--;
209         if (kip->nused == 0) {
210                 /*
211                  * Page is no longer in use.  Free it unless
212                  * it's the last one.  We keep the last one
213                  * so as not to have to set it up again the
214                  * next time somebody inserts a probe.
215                  */
216                 if (!list_is_singular(&kip->list)) {
217                         list_del_rcu(&kip->list);
218                         synchronize_rcu();
219                         kip->cache->free(kip->insns);
220                         kfree(kip);
221                 }
222                 return 1;
223         }
224         return 0;
225 }
226 
227 static int collect_garbage_slots(struct kprobe_insn_cache *c)
228 {
229         struct kprobe_insn_page *kip, *next;
230 
231         /* Ensure no-one is interrupted on the garbages */
232         synchronize_sched();
233 
234         list_for_each_entry_safe(kip, next, &c->pages, list) {
235                 int i;
236                 if (kip->ngarbage == 0)
237                         continue;
238                 kip->ngarbage = 0;      /* we will collect all garbages */
239                 for (i = 0; i < slots_per_page(c); i++) {
240                         if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i))
241                                 break;
242                 }
243         }
244         c->nr_garbage = 0;
245         return 0;
246 }
247 
248 void __free_insn_slot(struct kprobe_insn_cache *c,
249                       kprobe_opcode_t *slot, int dirty)
250 {
251         struct kprobe_insn_page *kip;
252         long idx;
253 
254         mutex_lock(&c->mutex);
255         rcu_read_lock();
256         list_for_each_entry_rcu(kip, &c->pages, list) {
257                 idx = ((long)slot - (long)kip->insns) /
258                         (c->insn_size * sizeof(kprobe_opcode_t));
259                 if (idx >= 0 && idx < slots_per_page(c))
260                         goto out;
261         }
262         /* Could not find this slot. */
263         WARN_ON(1);
264         kip = NULL;
265 out:
266         rcu_read_unlock();
267         /* Mark and sweep: this may sleep */
268         if (kip) {
269                 /* Check double free */
270                 WARN_ON(kip->slot_used[idx] != SLOT_USED);
271                 if (dirty) {
272                         kip->slot_used[idx] = SLOT_DIRTY;
273                         kip->ngarbage++;
274                         if (++c->nr_garbage > slots_per_page(c))
275                                 collect_garbage_slots(c);
276                 } else {
277                         collect_one_slot(kip, idx);
278                 }
279         }
280         mutex_unlock(&c->mutex);
281 }
282 
283 /*
284  * Check given address is on the page of kprobe instruction slots.
285  * This will be used for checking whether the address on a stack
286  * is on a text area or not.
287  */
288 bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
289 {
290         struct kprobe_insn_page *kip;
291         bool ret = false;
292 
293         rcu_read_lock();
294         list_for_each_entry_rcu(kip, &c->pages, list) {
295                 if (addr >= (unsigned long)kip->insns &&
296                     addr < (unsigned long)kip->insns + PAGE_SIZE) {
297                         ret = true;
298                         break;
299                 }
300         }
301         rcu_read_unlock();
302 
303         return ret;
304 }
305 
306 #ifdef CONFIG_OPTPROBES
307 /* For optimized_kprobe buffer */
308 struct kprobe_insn_cache kprobe_optinsn_slots = {
309         .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
310         .alloc = alloc_insn_page,
311         .free = free_insn_page,
312         .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
313         /* .insn_size is initialized later */
314         .nr_garbage = 0,
315 };
316 #endif
317 #endif
318 
319 /* We have preemption disabled.. so it is safe to use __ versions */
320 static inline void set_kprobe_instance(struct kprobe *kp)
321 {
322         __this_cpu_write(kprobe_instance, kp);
323 }
324 
325 static inline void reset_kprobe_instance(void)
326 {
327         __this_cpu_write(kprobe_instance, NULL);
328 }
329 
330 /*
331  * This routine is called either:
332  *      - under the kprobe_mutex - during kprobe_[un]register()
333  *                              OR
334  *      - with preemption disabled - from arch/xxx/kernel/kprobes.c
335  */
336 struct kprobe *get_kprobe(void *addr)
337 {
338         struct hlist_head *head;
339         struct kprobe *p;
340 
341         head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
342         hlist_for_each_entry_rcu(p, head, hlist) {
343                 if (p->addr == addr)
344                         return p;
345         }
346 
347         return NULL;
348 }
349 NOKPROBE_SYMBOL(get_kprobe);
350 
351 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
352 
353 /* Return true if the kprobe is an aggregator */
354 static inline int kprobe_aggrprobe(struct kprobe *p)
355 {
356         return p->pre_handler == aggr_pre_handler;
357 }
358 
359 /* Return true(!0) if the kprobe is unused */
360 static inline int kprobe_unused(struct kprobe *p)
361 {
362         return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
363                list_empty(&p->list);
364 }
365 
366 /*
367  * Keep all fields in the kprobe consistent
368  */
369 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
370 {
371         memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
372         memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
373 }
374 
375 #ifdef CONFIG_OPTPROBES
376 /* NOTE: change this value only with kprobe_mutex held */
377 static bool kprobes_allow_optimization;
378 
379 /*
380  * Call all pre_handler on the list, but ignores its return value.
381  * This must be called from arch-dep optimized caller.
382  */
383 void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
384 {
385         struct kprobe *kp;
386 
387         list_for_each_entry_rcu(kp, &p->list, list) {
388                 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
389                         set_kprobe_instance(kp);
390                         kp->pre_handler(kp, regs);
391                 }
392                 reset_kprobe_instance();
393         }
394 }
395 NOKPROBE_SYMBOL(opt_pre_handler);
396 
397 /* Free optimized instructions and optimized_kprobe */
398 static void free_aggr_kprobe(struct kprobe *p)
399 {
400         struct optimized_kprobe *op;
401 
402         op = container_of(p, struct optimized_kprobe, kp);
403         arch_remove_optimized_kprobe(op);
404         arch_remove_kprobe(p);
405         kfree(op);
406 }
407 
408 /* Return true(!0) if the kprobe is ready for optimization. */
409 static inline int kprobe_optready(struct kprobe *p)
410 {
411         struct optimized_kprobe *op;
412 
413         if (kprobe_aggrprobe(p)) {
414                 op = container_of(p, struct optimized_kprobe, kp);
415                 return arch_prepared_optinsn(&op->optinsn);
416         }
417 
418         return 0;
419 }
420 
421 /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
422 static inline int kprobe_disarmed(struct kprobe *p)
423 {
424         struct optimized_kprobe *op;
425 
426         /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
427         if (!kprobe_aggrprobe(p))
428                 return kprobe_disabled(p);
429 
430         op = container_of(p, struct optimized_kprobe, kp);
431 
432         return kprobe_disabled(p) && list_empty(&op->list);
433 }
434 
435 /* Return true(!0) if the probe is queued on (un)optimizing lists */
436 static int kprobe_queued(struct kprobe *p)
437 {
438         struct optimized_kprobe *op;
439 
440         if (kprobe_aggrprobe(p)) {
441                 op = container_of(p, struct optimized_kprobe, kp);
442                 if (!list_empty(&op->list))
443                         return 1;
444         }
445         return 0;
446 }
447 
448 /*
449  * Return an optimized kprobe whose optimizing code replaces
450  * instructions including addr (exclude breakpoint).
451  */
452 static struct kprobe *get_optimized_kprobe(unsigned long addr)
453 {
454         int i;
455         struct kprobe *p = NULL;
456         struct optimized_kprobe *op;
457 
458         /* Don't check i == 0, since that is a breakpoint case. */
459         for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
460                 p = get_kprobe((void *)(addr - i));
461 
462         if (p && kprobe_optready(p)) {
463                 op = container_of(p, struct optimized_kprobe, kp);
464                 if (arch_within_optimized_kprobe(op, addr))
465                         return p;
466         }
467 
468         return NULL;
469 }
470 
471 /* Optimization staging list, protected by kprobe_mutex */
472 static LIST_HEAD(optimizing_list);
473 static LIST_HEAD(unoptimizing_list);
474 static LIST_HEAD(freeing_list);
475 
476 static void kprobe_optimizer(struct work_struct *work);
477 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
478 #define OPTIMIZE_DELAY 5
479 
480 /*
481  * Optimize (replace a breakpoint with a jump) kprobes listed on
482  * optimizing_list.
483  */
484 static void do_optimize_kprobes(void)
485 {
486         /*
487          * The optimization/unoptimization refers online_cpus via
488          * stop_machine() and cpu-hotplug modifies online_cpus.
489          * And same time, text_mutex will be held in cpu-hotplug and here.
490          * This combination can cause a deadlock (cpu-hotplug try to lock
491          * text_mutex but stop_machine can not be done because online_cpus
492          * has been changed)
493          * To avoid this deadlock, caller must have locked cpu hotplug
494          * for preventing cpu-hotplug outside of text_mutex locking.
495          */
496         lockdep_assert_cpus_held();
497 
498         /* Optimization never be done when disarmed */
499         if (kprobes_all_disarmed || !kprobes_allow_optimization ||
500             list_empty(&optimizing_list))
501                 return;
502 
503         mutex_lock(&text_mutex);
504         arch_optimize_kprobes(&optimizing_list);
505         mutex_unlock(&text_mutex);
506 }
507 
508 /*
509  * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
510  * if need) kprobes listed on unoptimizing_list.
511  */
512 static void do_unoptimize_kprobes(void)
513 {
514         struct optimized_kprobe *op, *tmp;
515 
516         /* See comment in do_optimize_kprobes() */
517         lockdep_assert_cpus_held();
518 
519         /* Unoptimization must be done anytime */
520         if (list_empty(&unoptimizing_list))
521                 return;
522 
523         mutex_lock(&text_mutex);
524         arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
525         /* Loop free_list for disarming */
526         list_for_each_entry_safe(op, tmp, &freeing_list, list) {
527                 /* Disarm probes if marked disabled */
528                 if (kprobe_disabled(&op->kp))
529                         arch_disarm_kprobe(&op->kp);
530                 if (kprobe_unused(&op->kp)) {
531                         /*
532                          * Remove unused probes from hash list. After waiting
533                          * for synchronization, these probes are reclaimed.
534                          * (reclaiming is done by do_free_cleaned_kprobes.)
535                          */
536                         hlist_del_rcu(&op->kp.hlist);
537                 } else
538                         list_del_init(&op->list);
539         }
540         mutex_unlock(&text_mutex);
541 }
542 
543 /* Reclaim all kprobes on the free_list */
544 static void do_free_cleaned_kprobes(void)
545 {
546         struct optimized_kprobe *op, *tmp;
547 
548         list_for_each_entry_safe(op, tmp, &freeing_list, list) {
549                 BUG_ON(!kprobe_unused(&op->kp));
550                 list_del_init(&op->list);
551                 free_aggr_kprobe(&op->kp);
552         }
553 }
554 
555 /* Start optimizer after OPTIMIZE_DELAY passed */
556 static void kick_kprobe_optimizer(void)
557 {
558         schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
559 }
560 
561 /* Kprobe jump optimizer */
562 static void kprobe_optimizer(struct work_struct *work)
563 {
564         mutex_lock(&kprobe_mutex);
565         cpus_read_lock();
566         /* Lock modules while optimizing kprobes */
567         mutex_lock(&module_mutex);
568 
569         /*
570          * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
571          * kprobes before waiting for quiesence period.
572          */
573         do_unoptimize_kprobes();
574 
575         /*
576          * Step 2: Wait for quiesence period to ensure all potentially
577          * preempted tasks to have normally scheduled. Because optprobe
578          * may modify multiple instructions, there is a chance that Nth
579          * instruction is preempted. In that case, such tasks can return
580          * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
581          * Note that on non-preemptive kernel, this is transparently converted
582          * to synchronoze_sched() to wait for all interrupts to have completed.
583          */
584         synchronize_rcu_tasks();
585 
586         /* Step 3: Optimize kprobes after quiesence period */
587         do_optimize_kprobes();
588 
589         /* Step 4: Free cleaned kprobes after quiesence period */
590         do_free_cleaned_kprobes();
591 
592         mutex_unlock(&module_mutex);
593         cpus_read_unlock();
594         mutex_unlock(&kprobe_mutex);
595 
596         /* Step 5: Kick optimizer again if needed */
597         if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
598                 kick_kprobe_optimizer();
599 }
600 
601 /* Wait for completing optimization and unoptimization */
602 void wait_for_kprobe_optimizer(void)
603 {
604         mutex_lock(&kprobe_mutex);
605 
606         while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
607                 mutex_unlock(&kprobe_mutex);
608 
609                 /* this will also make optimizing_work execute immmediately */
610                 flush_delayed_work(&optimizing_work);
611                 /* @optimizing_work might not have been queued yet, relax */
612                 cpu_relax();
613 
614                 mutex_lock(&kprobe_mutex);
615         }
616 
617         mutex_unlock(&kprobe_mutex);
618 }
619 
620 /* Optimize kprobe if p is ready to be optimized */
621 static void optimize_kprobe(struct kprobe *p)
622 {
623         struct optimized_kprobe *op;
624 
625         /* Check if the kprobe is disabled or not ready for optimization. */
626         if (!kprobe_optready(p) || !kprobes_allow_optimization ||
627             (kprobe_disabled(p) || kprobes_all_disarmed))
628                 return;
629 
630         /* Both of break_handler and post_handler are not supported. */
631         if (p->break_handler || p->post_handler)
632                 return;
633 
634         op = container_of(p, struct optimized_kprobe, kp);
635 
636         /* Check there is no other kprobes at the optimized instructions */
637         if (arch_check_optimized_kprobe(op) < 0)
638                 return;
639 
640         /* Check if it is already optimized. */
641         if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
642                 return;
643         op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
644 
645         if (!list_empty(&op->list))
646                 /* This is under unoptimizing. Just dequeue the probe */
647                 list_del_init(&op->list);
648         else {
649                 list_add(&op->list, &optimizing_list);
650                 kick_kprobe_optimizer();
651         }
652 }
653 
654 /* Short cut to direct unoptimizing */
655 static void force_unoptimize_kprobe(struct optimized_kprobe *op)
656 {
657         lockdep_assert_cpus_held();
658         arch_unoptimize_kprobe(op);
659         if (kprobe_disabled(&op->kp))
660                 arch_disarm_kprobe(&op->kp);
661 }
662 
663 /* Unoptimize a kprobe if p is optimized */
664 static void unoptimize_kprobe(struct kprobe *p, bool force)
665 {
666         struct optimized_kprobe *op;
667 
668         if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
669                 return; /* This is not an optprobe nor optimized */
670 
671         op = container_of(p, struct optimized_kprobe, kp);
672         if (!kprobe_optimized(p)) {
673                 /* Unoptimized or unoptimizing case */
674                 if (force && !list_empty(&op->list)) {
675                         /*
676                          * Only if this is unoptimizing kprobe and forced,
677                          * forcibly unoptimize it. (No need to unoptimize
678                          * unoptimized kprobe again :)
679                          */
680                         list_del_init(&op->list);
681                         force_unoptimize_kprobe(op);
682                 }
683                 return;
684         }
685 
686         op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
687         if (!list_empty(&op->list)) {
688                 /* Dequeue from the optimization queue */
689                 list_del_init(&op->list);
690                 return;
691         }
692         /* Optimized kprobe case */
693         if (force)
694                 /* Forcibly update the code: this is a special case */
695                 force_unoptimize_kprobe(op);
696         else {
697                 list_add(&op->list, &unoptimizing_list);
698                 kick_kprobe_optimizer();
699         }
700 }
701 
702 /* Cancel unoptimizing for reusing */
703 static void reuse_unused_kprobe(struct kprobe *ap)
704 {
705         struct optimized_kprobe *op;
706 
707         BUG_ON(!kprobe_unused(ap));
708         /*
709          * Unused kprobe MUST be on the way of delayed unoptimizing (means
710          * there is still a relative jump) and disabled.
711          */
712         op = container_of(ap, struct optimized_kprobe, kp);
713         if (unlikely(list_empty(&op->list)))
714                 printk(KERN_WARNING "Warning: found a stray unused "
715                         "aggrprobe@%p\n", ap->addr);
716         /* Enable the probe again */
717         ap->flags &= ~KPROBE_FLAG_DISABLED;
718         /* Optimize it again (remove from op->list) */
719         BUG_ON(!kprobe_optready(ap));
720         optimize_kprobe(ap);
721 }
722 
723 /* Remove optimized instructions */
724 static void kill_optimized_kprobe(struct kprobe *p)
725 {
726         struct optimized_kprobe *op;
727 
728         op = container_of(p, struct optimized_kprobe, kp);
729         if (!list_empty(&op->list))
730                 /* Dequeue from the (un)optimization queue */
731                 list_del_init(&op->list);
732         op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
733 
734         if (kprobe_unused(p)) {
735                 /* Enqueue if it is unused */
736                 list_add(&op->list, &freeing_list);
737                 /*
738                  * Remove unused probes from the hash list. After waiting
739                  * for synchronization, this probe is reclaimed.
740                  * (reclaiming is done by do_free_cleaned_kprobes().)
741                  */
742                 hlist_del_rcu(&op->kp.hlist);
743         }
744 
745         /* Don't touch the code, because it is already freed. */
746         arch_remove_optimized_kprobe(op);
747 }
748 
749 static inline
750 void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
751 {
752         if (!kprobe_ftrace(p))
753                 arch_prepare_optimized_kprobe(op, p);
754 }
755 
756 /* Try to prepare optimized instructions */
757 static void prepare_optimized_kprobe(struct kprobe *p)
758 {
759         struct optimized_kprobe *op;
760 
761         op = container_of(p, struct optimized_kprobe, kp);
762         __prepare_optimized_kprobe(op, p);
763 }
764 
765 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
766 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
767 {
768         struct optimized_kprobe *op;
769 
770         op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
771         if (!op)
772                 return NULL;
773 
774         INIT_LIST_HEAD(&op->list);
775         op->kp.addr = p->addr;
776         __prepare_optimized_kprobe(op, p);
777 
778         return &op->kp;
779 }
780 
781 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
782 
783 /*
784  * Prepare an optimized_kprobe and optimize it
785  * NOTE: p must be a normal registered kprobe
786  */
787 static void try_to_optimize_kprobe(struct kprobe *p)
788 {
789         struct kprobe *ap;
790         struct optimized_kprobe *op;
791 
792         /* Impossible to optimize ftrace-based kprobe */
793         if (kprobe_ftrace(p))
794                 return;
795 
796         /* For preparing optimization, jump_label_text_reserved() is called */
797         cpus_read_lock();
798         jump_label_lock();
799         mutex_lock(&text_mutex);
800 
801         ap = alloc_aggr_kprobe(p);
802         if (!ap)
803                 goto out;
804 
805         op = container_of(ap, struct optimized_kprobe, kp);
806         if (!arch_prepared_optinsn(&op->optinsn)) {
807                 /* If failed to setup optimizing, fallback to kprobe */
808                 arch_remove_optimized_kprobe(op);
809                 kfree(op);
810                 goto out;
811         }
812 
813         init_aggr_kprobe(ap, p);
814         optimize_kprobe(ap);    /* This just kicks optimizer thread */
815 
816 out:
817         mutex_unlock(&text_mutex);
818         jump_label_unlock();
819         cpus_read_unlock();
820 }
821 
822 #ifdef CONFIG_SYSCTL
823 static void optimize_all_kprobes(void)
824 {
825         struct hlist_head *head;
826         struct kprobe *p;
827         unsigned int i;
828 
829         mutex_lock(&kprobe_mutex);
830         /* If optimization is already allowed, just return */
831         if (kprobes_allow_optimization)
832                 goto out;
833 
834         cpus_read_lock();
835         kprobes_allow_optimization = true;
836         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
837                 head = &kprobe_table[i];
838                 hlist_for_each_entry_rcu(p, head, hlist)
839                         if (!kprobe_disabled(p))
840                                 optimize_kprobe(p);
841         }
842         cpus_read_unlock();
843         printk(KERN_INFO "Kprobes globally optimized\n");
844 out:
845         mutex_unlock(&kprobe_mutex);
846 }
847 
848 static void unoptimize_all_kprobes(void)
849 {
850         struct hlist_head *head;
851         struct kprobe *p;
852         unsigned int i;
853 
854         mutex_lock(&kprobe_mutex);
855         /* If optimization is already prohibited, just return */
856         if (!kprobes_allow_optimization) {
857                 mutex_unlock(&kprobe_mutex);
858                 return;
859         }
860 
861         cpus_read_lock();
862         kprobes_allow_optimization = false;
863         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
864                 head = &kprobe_table[i];
865                 hlist_for_each_entry_rcu(p, head, hlist) {
866                         if (!kprobe_disabled(p))
867                                 unoptimize_kprobe(p, false);
868                 }
869         }
870         cpus_read_unlock();
871         mutex_unlock(&kprobe_mutex);
872 
873         /* Wait for unoptimizing completion */
874         wait_for_kprobe_optimizer();
875         printk(KERN_INFO "Kprobes globally unoptimized\n");
876 }
877 
878 static DEFINE_MUTEX(kprobe_sysctl_mutex);
879 int sysctl_kprobes_optimization;
880 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
881                                       void __user *buffer, size_t *length,
882                                       loff_t *ppos)
883 {
884         int ret;
885 
886         mutex_lock(&kprobe_sysctl_mutex);
887         sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
888         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
889 
890         if (sysctl_kprobes_optimization)
891                 optimize_all_kprobes();
892         else
893                 unoptimize_all_kprobes();
894         mutex_unlock(&kprobe_sysctl_mutex);
895 
896         return ret;
897 }
898 #endif /* CONFIG_SYSCTL */
899 
900 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
901 static void __arm_kprobe(struct kprobe *p)
902 {
903         struct kprobe *_p;
904 
905         /* Check collision with other optimized kprobes */
906         _p = get_optimized_kprobe((unsigned long)p->addr);
907         if (unlikely(_p))
908                 /* Fallback to unoptimized kprobe */
909                 unoptimize_kprobe(_p, true);
910 
911         arch_arm_kprobe(p);
912         optimize_kprobe(p);     /* Try to optimize (add kprobe to a list) */
913 }
914 
915 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
916 static void __disarm_kprobe(struct kprobe *p, bool reopt)
917 {
918         struct kprobe *_p;
919 
920         /* Try to unoptimize */
921         unoptimize_kprobe(p, kprobes_all_disarmed);
922 
923         if (!kprobe_queued(p)) {
924                 arch_disarm_kprobe(p);
925                 /* If another kprobe was blocked, optimize it. */
926                 _p = get_optimized_kprobe((unsigned long)p->addr);
927                 if (unlikely(_p) && reopt)
928                         optimize_kprobe(_p);
929         }
930         /* TODO: reoptimize others after unoptimized this probe */
931 }
932 
933 #else /* !CONFIG_OPTPROBES */
934 
935 #define optimize_kprobe(p)                      do {} while (0)
936 #define unoptimize_kprobe(p, f)                 do {} while (0)
937 #define kill_optimized_kprobe(p)                do {} while (0)
938 #define prepare_optimized_kprobe(p)             do {} while (0)
939 #define try_to_optimize_kprobe(p)               do {} while (0)
940 #define __arm_kprobe(p)                         arch_arm_kprobe(p)
941 #define __disarm_kprobe(p, o)                   arch_disarm_kprobe(p)
942 #define kprobe_disarmed(p)                      kprobe_disabled(p)
943 #define wait_for_kprobe_optimizer()             do {} while (0)
944 
945 /* There should be no unused kprobes can be reused without optimization */
946 static void reuse_unused_kprobe(struct kprobe *ap)
947 {
948         printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
949         BUG_ON(kprobe_unused(ap));
950 }
951 
952 static void free_aggr_kprobe(struct kprobe *p)
953 {
954         arch_remove_kprobe(p);
955         kfree(p);
956 }
957 
958 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
959 {
960         return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
961 }
962 #endif /* CONFIG_OPTPROBES */
963 
964 #ifdef CONFIG_KPROBES_ON_FTRACE
965 static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
966         .func = kprobe_ftrace_handler,
967         .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
968 };
969 static int kprobe_ftrace_enabled;
970 
971 /* Must ensure p->addr is really on ftrace */
972 static int prepare_kprobe(struct kprobe *p)
973 {
974         if (!kprobe_ftrace(p))
975                 return arch_prepare_kprobe(p);
976 
977         return arch_prepare_kprobe_ftrace(p);
978 }
979 
980 /* Caller must lock kprobe_mutex */
981 static int arm_kprobe_ftrace(struct kprobe *p)
982 {
983         int ret = 0;
984 
985         ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
986                                    (unsigned long)p->addr, 0, 0);
987         if (ret) {
988                 pr_debug("Failed to arm kprobe-ftrace at %p (%d)\n", p->addr, ret);
989                 return ret;
990         }
991 
992         if (kprobe_ftrace_enabled == 0) {
993                 ret = register_ftrace_function(&kprobe_ftrace_ops);
994                 if (ret) {
995                         pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
996                         goto err_ftrace;
997                 }
998         }
999 
1000         kprobe_ftrace_enabled++;
1001         return ret;
1002 
1003 err_ftrace:
1004         /*
1005          * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
1006          * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
1007          * empty filter_hash which would undesirably trace all functions.
1008          */
1009         ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
1010         return ret;
1011 }
1012 
1013 /* Caller must lock kprobe_mutex */
1014 static int disarm_kprobe_ftrace(struct kprobe *p)
1015 {
1016         int ret = 0;
1017 
1018         if (kprobe_ftrace_enabled == 1) {
1019                 ret = unregister_ftrace_function(&kprobe_ftrace_ops);
1020                 if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
1021                         return ret;
1022         }
1023 
1024         kprobe_ftrace_enabled--;
1025 
1026         ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
1027                            (unsigned long)p->addr, 1, 0);
1028         WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
1029         return ret;
1030 }
1031 #else   /* !CONFIG_KPROBES_ON_FTRACE */
1032 #define prepare_kprobe(p)       arch_prepare_kprobe(p)
1033 #define arm_kprobe_ftrace(p)    (-ENODEV)
1034 #define disarm_kprobe_ftrace(p) (-ENODEV)
1035 #endif
1036 
1037 /* Arm a kprobe with text_mutex */
1038 static int arm_kprobe(struct kprobe *kp)
1039 {
1040         if (unlikely(kprobe_ftrace(kp)))
1041                 return arm_kprobe_ftrace(kp);
1042 
1043         cpus_read_lock();
1044         mutex_lock(&text_mutex);
1045         __arm_kprobe(kp);
1046         mutex_unlock(&text_mutex);
1047         cpus_read_unlock();
1048 
1049         return 0;
1050 }
1051 
1052 /* Disarm a kprobe with text_mutex */
1053 static int disarm_kprobe(struct kprobe *kp, bool reopt)
1054 {
1055         if (unlikely(kprobe_ftrace(kp)))
1056                 return disarm_kprobe_ftrace(kp);
1057 
1058         cpus_read_lock();
1059         mutex_lock(&text_mutex);
1060         __disarm_kprobe(kp, reopt);
1061         mutex_unlock(&text_mutex);
1062         cpus_read_unlock();
1063 
1064         return 0;
1065 }
1066 
1067 /*
1068  * Aggregate handlers for multiple kprobes support - these handlers
1069  * take care of invoking the individual kprobe handlers on p->list
1070  */
1071 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
1072 {
1073         struct kprobe *kp;
1074 
1075         list_for_each_entry_rcu(kp, &p->list, list) {
1076                 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
1077                         set_kprobe_instance(kp);
1078                         if (kp->pre_handler(kp, regs))
1079                                 return 1;
1080                 }
1081                 reset_kprobe_instance();
1082         }
1083         return 0;
1084 }
1085 NOKPROBE_SYMBOL(aggr_pre_handler);
1086 
1087 static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1088                               unsigned long flags)
1089 {
1090         struct kprobe *kp;
1091 
1092         list_for_each_entry_rcu(kp, &p->list, list) {
1093                 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
1094                         set_kprobe_instance(kp);
1095                         kp->post_handler(kp, regs, flags);
1096                         reset_kprobe_instance();
1097                 }
1098         }
1099 }
1100 NOKPROBE_SYMBOL(aggr_post_handler);
1101 
1102 static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
1103                               int trapnr)
1104 {
1105         struct kprobe *cur = __this_cpu_read(kprobe_instance);
1106 
1107         /*
1108          * if we faulted "during" the execution of a user specified
1109          * probe handler, invoke just that probe's fault handler
1110          */
1111         if (cur && cur->fault_handler) {
1112                 if (cur->fault_handler(cur, regs, trapnr))
1113                         return 1;
1114         }
1115         return 0;
1116 }
1117 NOKPROBE_SYMBOL(aggr_fault_handler);
1118 
1119 static int aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
1120 {
1121         struct kprobe *cur = __this_cpu_read(kprobe_instance);
1122         int ret = 0;
1123 
1124         if (cur && cur->break_handler) {
1125                 if (cur->break_handler(cur, regs))
1126                         ret = 1;
1127         }
1128         reset_kprobe_instance();
1129         return ret;
1130 }
1131 NOKPROBE_SYMBOL(aggr_break_handler);
1132 
1133 /* Walks the list and increments nmissed count for multiprobe case */
1134 void kprobes_inc_nmissed_count(struct kprobe *p)
1135 {
1136         struct kprobe *kp;
1137         if (!kprobe_aggrprobe(p)) {
1138                 p->nmissed++;
1139         } else {
1140                 list_for_each_entry_rcu(kp, &p->list, list)
1141                         kp->nmissed++;
1142         }
1143         return;
1144 }
1145 NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
1146 
1147 void recycle_rp_inst(struct kretprobe_instance *ri,
1148                      struct hlist_head *head)
1149 {
1150         struct kretprobe *rp = ri->rp;
1151 
1152         /* remove rp inst off the rprobe_inst_table */
1153         hlist_del(&ri->hlist);
1154         INIT_HLIST_NODE(&ri->hlist);
1155         if (likely(rp)) {
1156                 raw_spin_lock(&rp->lock);
1157                 hlist_add_head(&ri->hlist, &rp->free_instances);
1158                 raw_spin_unlock(&rp->lock);
1159         } else
1160                 /* Unregistering */
1161                 hlist_add_head(&ri->hlist, head);
1162 }
1163 NOKPROBE_SYMBOL(recycle_rp_inst);
1164 
1165 void kretprobe_hash_lock(struct task_struct *tsk,
1166                          struct hlist_head **head, unsigned long *flags)
1167 __acquires(hlist_lock)
1168 {
1169         unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1170         raw_spinlock_t *hlist_lock;
1171 
1172         *head = &kretprobe_inst_table[hash];
1173         hlist_lock = kretprobe_table_lock_ptr(hash);
1174         raw_spin_lock_irqsave(hlist_lock, *flags);
1175 }
1176 NOKPROBE_SYMBOL(kretprobe_hash_lock);
1177 
1178 static void kretprobe_table_lock(unsigned long hash,
1179                                  unsigned long *flags)
1180 __acquires(hlist_lock)
1181 {
1182         raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1183         raw_spin_lock_irqsave(hlist_lock, *flags);
1184 }
1185 NOKPROBE_SYMBOL(kretprobe_table_lock);
1186 
1187 void kretprobe_hash_unlock(struct task_struct *tsk,
1188                            unsigned long *flags)
1189 __releases(hlist_lock)
1190 {
1191         unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1192         raw_spinlock_t *hlist_lock;
1193 
1194         hlist_lock = kretprobe_table_lock_ptr(hash);
1195         raw_spin_unlock_irqrestore(hlist_lock, *flags);
1196 }
1197 NOKPROBE_SYMBOL(kretprobe_hash_unlock);
1198 
1199 static void kretprobe_table_unlock(unsigned long hash,
1200                                    unsigned long *flags)
1201 __releases(hlist_lock)
1202 {
1203         raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1204         raw_spin_unlock_irqrestore(hlist_lock, *flags);
1205 }
1206 NOKPROBE_SYMBOL(kretprobe_table_unlock);
1207 
1208 /*
1209  * This function is called from finish_task_switch when task tk becomes dead,
1210  * so that we can recycle any function-return probe instances associated
1211  * with this task. These left over instances represent probed functions
1212  * that have been called but will never return.
1213  */
1214 void kprobe_flush_task(struct task_struct *tk)
1215 {
1216         struct kretprobe_instance *ri;
1217         struct hlist_head *head, empty_rp;
1218         struct hlist_node *tmp;
1219         unsigned long hash, flags = 0;
1220 
1221         if (unlikely(!kprobes_initialized))
1222                 /* Early boot.  kretprobe_table_locks not yet initialized. */
1223                 return;
1224 
1225         INIT_HLIST_HEAD(&empty_rp);
1226         hash = hash_ptr(tk, KPROBE_HASH_BITS);
1227         head = &kretprobe_inst_table[hash];
1228         kretprobe_table_lock(hash, &flags);
1229         hlist_for_each_entry_safe(ri, tmp, head, hlist) {
1230                 if (ri->task == tk)
1231                         recycle_rp_inst(ri, &empty_rp);
1232         }
1233         kretprobe_table_unlock(hash, &flags);
1234         hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
1235                 hlist_del(&ri->hlist);
1236                 kfree(ri);
1237         }
1238 }
1239 NOKPROBE_SYMBOL(kprobe_flush_task);
1240 
1241 static inline void free_rp_inst(struct kretprobe *rp)
1242 {
1243         struct kretprobe_instance *ri;
1244         struct hlist_node *next;
1245 
1246         hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
1247                 hlist_del(&ri->hlist);
1248                 kfree(ri);
1249         }
1250 }
1251 
1252 static void cleanup_rp_inst(struct kretprobe *rp)
1253 {
1254         unsigned long flags, hash;
1255         struct kretprobe_instance *ri;
1256         struct hlist_node *next;
1257         struct hlist_head *head;
1258 
1259         /* No race here */
1260         for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1261                 kretprobe_table_lock(hash, &flags);
1262                 head = &kretprobe_inst_table[hash];
1263                 hlist_for_each_entry_safe(ri, next, head, hlist) {
1264                         if (ri->rp == rp)
1265                                 ri->rp = NULL;
1266                 }
1267                 kretprobe_table_unlock(hash, &flags);
1268         }
1269         free_rp_inst(rp);
1270 }
1271 NOKPROBE_SYMBOL(cleanup_rp_inst);
1272 
1273 /*
1274 * Add the new probe to ap->list. Fail if this is the
1275 * second jprobe at the address - two jprobes can't coexist
1276 */
1277 static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1278 {
1279         BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
1280 
1281         if (p->break_handler || p->post_handler)
1282                 unoptimize_kprobe(ap, true);    /* Fall back to normal kprobe */
1283 
1284         if (p->break_handler) {
1285                 if (ap->break_handler)
1286                         return -EEXIST;
1287                 list_add_tail_rcu(&p->list, &ap->list);
1288                 ap->break_handler = aggr_break_handler;
1289         } else
1290                 list_add_rcu(&p->list, &ap->list);
1291         if (p->post_handler && !ap->post_handler)
1292                 ap->post_handler = aggr_post_handler;
1293 
1294         return 0;
1295 }
1296 
1297 /*
1298  * Fill in the required fields of the "manager kprobe". Replace the
1299  * earlier kprobe in the hlist with the manager kprobe
1300  */
1301 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1302 {
1303         /* Copy p's insn slot to ap */
1304         copy_kprobe(p, ap);
1305         flush_insn_slot(ap);
1306         ap->addr = p->addr;
1307         ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1308         ap->pre_handler = aggr_pre_handler;
1309         ap->fault_handler = aggr_fault_handler;
1310         /* We don't care the kprobe which has gone. */
1311         if (p->post_handler && !kprobe_gone(p))
1312                 ap->post_handler = aggr_post_handler;
1313         if (p->break_handler && !kprobe_gone(p))
1314                 ap->break_handler = aggr_break_handler;
1315 
1316         INIT_LIST_HEAD(&ap->list);
1317         INIT_HLIST_NODE(&ap->hlist);
1318 
1319         list_add_rcu(&p->list, &ap->list);
1320         hlist_replace_rcu(&p->hlist, &ap->hlist);
1321 }
1322 
1323 /*
1324  * This is the second or subsequent kprobe at the address - handle
1325  * the intricacies
1326  */
1327 static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
1328 {
1329         int ret = 0;
1330         struct kprobe *ap = orig_p;
1331 
1332         cpus_read_lock();
1333 
1334         /* For preparing optimization, jump_label_text_reserved() is called */
1335         jump_label_lock();
1336         mutex_lock(&text_mutex);
1337 
1338         if (!kprobe_aggrprobe(orig_p)) {
1339                 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1340                 ap = alloc_aggr_kprobe(orig_p);
1341                 if (!ap) {
1342                         ret = -ENOMEM;
1343                         goto out;
1344                 }
1345                 init_aggr_kprobe(ap, orig_p);
1346         } else if (kprobe_unused(ap))
1347                 /* This probe is going to die. Rescue it */
1348                 reuse_unused_kprobe(ap);
1349 
1350         if (kprobe_gone(ap)) {
1351                 /*
1352                  * Attempting to insert new probe at the same location that
1353                  * had a probe in the module vaddr area which already
1354                  * freed. So, the instruction slot has already been
1355                  * released. We need a new slot for the new probe.
1356                  */
1357                 ret = arch_prepare_kprobe(ap);
1358                 if (ret)
1359                         /*
1360                          * Even if fail to allocate new slot, don't need to
1361                          * free aggr_probe. It will be used next time, or
1362                          * freed by unregister_kprobe.
1363                          */
1364                         goto out;
1365 
1366                 /* Prepare optimized instructions if possible. */
1367                 prepare_optimized_kprobe(ap);
1368 
1369                 /*
1370                  * Clear gone flag to prevent allocating new slot again, and
1371                  * set disabled flag because it is not armed yet.
1372                  */
1373                 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1374                             | KPROBE_FLAG_DISABLED;
1375         }
1376 
1377         /* Copy ap's insn slot to p */
1378         copy_kprobe(ap, p);
1379         ret = add_new_kprobe(ap, p);
1380 
1381 out:
1382         mutex_unlock(&text_mutex);
1383         jump_label_unlock();
1384         cpus_read_unlock();
1385 
1386         if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
1387                 ap->flags &= ~KPROBE_FLAG_DISABLED;
1388                 if (!kprobes_all_disarmed) {
1389                         /* Arm the breakpoint again. */
1390                         ret = arm_kprobe(ap);
1391                         if (ret) {
1392                                 ap->flags |= KPROBE_FLAG_DISABLED;
1393                                 list_del_rcu(&p->list);
1394                                 synchronize_sched();
1395                         }
1396                 }
1397         }
1398         return ret;
1399 }
1400 
1401 bool __weak arch_within_kprobe_blacklist(unsigned long addr)
1402 {
1403         /* The __kprobes marked functions and entry code must not be probed */
1404         return addr >= (unsigned long)__kprobes_text_start &&
1405                addr < (unsigned long)__kprobes_text_end;
1406 }
1407 
1408 bool within_kprobe_blacklist(unsigned long addr)
1409 {
1410         struct kprobe_blacklist_entry *ent;
1411 
1412         if (arch_within_kprobe_blacklist(addr))
1413                 return true;
1414         /*
1415          * If there exists a kprobe_blacklist, verify and
1416          * fail any probe registration in the prohibited area
1417          */
1418         list_for_each_entry(ent, &kprobe_blacklist, list) {
1419                 if (addr >= ent->start_addr && addr < ent->end_addr)
1420                         return true;
1421         }
1422 
1423         return false;
1424 }
1425 
1426 /*
1427  * If we have a symbol_name argument, look it up and add the offset field
1428  * to it. This way, we can specify a relative address to a symbol.
1429  * This returns encoded errors if it fails to look up symbol or invalid
1430  * combination of parameters.
1431  */
1432 static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
1433                         const char *symbol_name, unsigned int offset)
1434 {
1435         if ((symbol_name && addr) || (!symbol_name && !addr))
1436                 goto invalid;
1437 
1438         if (symbol_name) {
1439                 addr = kprobe_lookup_name(symbol_name, offset);
1440                 if (!addr)
1441                         return ERR_PTR(-ENOENT);
1442         }
1443 
1444         addr = (kprobe_opcode_t *)(((char *)addr) + offset);
1445         if (addr)
1446                 return addr;
1447 
1448 invalid:
1449         return ERR_PTR(-EINVAL);
1450 }
1451 
1452 static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
1453 {
1454         return _kprobe_addr(p->addr, p->symbol_name, p->offset);
1455 }
1456 
1457 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1458 static struct kprobe *__get_valid_kprobe(struct kprobe *p)
1459 {
1460         struct kprobe *ap, *list_p;
1461 
1462         ap = get_kprobe(p->addr);
1463         if (unlikely(!ap))
1464                 return NULL;
1465 
1466         if (p != ap) {
1467                 list_for_each_entry_rcu(list_p, &ap->list, list)
1468                         if (list_p == p)
1469                         /* kprobe p is a valid probe */
1470                                 goto valid;
1471                 return NULL;
1472         }
1473 valid:
1474         return ap;
1475 }
1476 
1477 /* Return error if the kprobe is being re-registered */
1478 static inline int check_kprobe_rereg(struct kprobe *p)
1479 {
1480         int ret = 0;
1481 
1482         mutex_lock(&kprobe_mutex);
1483         if (__get_valid_kprobe(p))
1484                 ret = -EINVAL;
1485         mutex_unlock(&kprobe_mutex);
1486 
1487         return ret;
1488 }
1489 
1490 int __weak arch_check_ftrace_location(struct kprobe *p)
1491 {
1492         unsigned long ftrace_addr;
1493 
1494         ftrace_addr = ftrace_location((unsigned long)p->addr);
1495         if (ftrace_addr) {
1496 #ifdef CONFIG_KPROBES_ON_FTRACE
1497                 /* Given address is not on the instruction boundary */
1498                 if ((unsigned long)p->addr != ftrace_addr)
1499                         return -EILSEQ;
1500                 p->flags |= KPROBE_FLAG_FTRACE;
1501 #else   /* !CONFIG_KPROBES_ON_FTRACE */
1502                 return -EINVAL;
1503 #endif
1504         }
1505         return 0;
1506 }
1507 
1508 static int check_kprobe_address_safe(struct kprobe *p,
1509                                      struct module **probed_mod)
1510 {
1511         int ret;
1512 
1513         ret = arch_check_ftrace_location(p);
1514         if (ret)
1515                 return ret;
1516         jump_label_lock();
1517         preempt_disable();
1518 
1519         /* Ensure it is not in reserved area nor out of text */
1520         if (!kernel_text_address((unsigned long) p->addr) ||
1521             within_kprobe_blacklist((unsigned long) p->addr) ||
1522             jump_label_text_reserved(p->addr, p->addr)) {
1523                 ret = -EINVAL;
1524                 goto out;
1525         }
1526 
1527         /* Check if are we probing a module */
1528         *probed_mod = __module_text_address((unsigned long) p->addr);
1529         if (*probed_mod) {
1530                 /*
1531                  * We must hold a refcount of the probed module while updating
1532                  * its code to prohibit unexpected unloading.
1533                  */
1534                 if (unlikely(!try_module_get(*probed_mod))) {
1535                         ret = -ENOENT;
1536                         goto out;
1537                 }
1538 
1539                 /*
1540                  * If the module freed .init.text, we couldn't insert
1541                  * kprobes in there.
1542                  */
1543                 if (within_module_init((unsigned long)p->addr, *probed_mod) &&
1544                     (*probed_mod)->state != MODULE_STATE_COMING) {
1545                         module_put(*probed_mod);
1546                         *probed_mod = NULL;
1547                         ret = -ENOENT;
1548                 }
1549         }
1550 out:
1551         preempt_enable();
1552         jump_label_unlock();
1553 
1554         return ret;
1555 }
1556 
1557 int register_kprobe(struct kprobe *p)
1558 {
1559         int ret;
1560         struct kprobe *old_p;
1561         struct module *probed_mod;
1562         kprobe_opcode_t *addr;
1563 
1564         /* Adjust probe address from symbol */
1565         addr = kprobe_addr(p);
1566         if (IS_ERR(addr))
1567                 return PTR_ERR(addr);
1568         p->addr = addr;
1569 
1570         ret = check_kprobe_rereg(p);
1571         if (ret)
1572                 return ret;
1573 
1574         /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1575         p->flags &= KPROBE_FLAG_DISABLED;
1576         p->nmissed = 0;
1577         INIT_LIST_HEAD(&p->list);
1578 
1579         ret = check_kprobe_address_safe(p, &probed_mod);
1580         if (ret)
1581                 return ret;
1582 
1583         mutex_lock(&kprobe_mutex);
1584 
1585         old_p = get_kprobe(p->addr);
1586         if (old_p) {
1587                 /* Since this may unoptimize old_p, locking text_mutex. */
1588                 ret = register_aggr_kprobe(old_p, p);
1589                 goto out;
1590         }
1591 
1592         cpus_read_lock();
1593         /* Prevent text modification */
1594         mutex_lock(&text_mutex);
1595         ret = prepare_kprobe(p);
1596         mutex_unlock(&text_mutex);
1597         cpus_read_unlock();
1598         if (ret)
1599                 goto out;
1600 
1601         INIT_HLIST_NODE(&p->hlist);
1602         hlist_add_head_rcu(&p->hlist,
1603                        &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1604 
1605         if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
1606                 ret = arm_kprobe(p);
1607                 if (ret) {
1608                         hlist_del_rcu(&p->hlist);
1609                         synchronize_sched();
1610                         goto out;
1611                 }
1612         }
1613 
1614         /* Try to optimize kprobe */
1615         try_to_optimize_kprobe(p);
1616 out:
1617         mutex_unlock(&kprobe_mutex);
1618 
1619         if (probed_mod)
1620                 module_put(probed_mod);
1621 
1622         return ret;
1623 }
1624 EXPORT_SYMBOL_GPL(register_kprobe);
1625 
1626 /* Check if all probes on the aggrprobe are disabled */
1627 static int aggr_kprobe_disabled(struct kprobe *ap)
1628 {
1629         struct kprobe *kp;
1630 
1631         list_for_each_entry_rcu(kp, &ap->list, list)
1632                 if (!kprobe_disabled(kp))
1633                         /*
1634                          * There is an active probe on the list.
1635                          * We can't disable this ap.
1636                          */
1637                         return 0;
1638 
1639         return 1;
1640 }
1641 
1642 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1643 static struct kprobe *__disable_kprobe(struct kprobe *p)
1644 {
1645         struct kprobe *orig_p;
1646         int ret;
1647 
1648         /* Get an original kprobe for return */
1649         orig_p = __get_valid_kprobe(p);
1650         if (unlikely(orig_p == NULL))
1651                 return ERR_PTR(-EINVAL);
1652 
1653         if (!kprobe_disabled(p)) {
1654                 /* Disable probe if it is a child probe */
1655                 if (p != orig_p)
1656                         p->flags |= KPROBE_FLAG_DISABLED;
1657 
1658                 /* Try to disarm and disable this/parent probe */
1659                 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1660                         /*
1661                          * If kprobes_all_disarmed is set, orig_p
1662                          * should have already been disarmed, so
1663                          * skip unneed disarming process.
1664                          */
1665                         if (!kprobes_all_disarmed) {
1666                                 ret = disarm_kprobe(orig_p, true);
1667                                 if (ret) {
1668                                         p->flags &= ~KPROBE_FLAG_DISABLED;
1669                                         return ERR_PTR(ret);
1670                                 }
1671                         }
1672                         orig_p->flags |= KPROBE_FLAG_DISABLED;
1673                 }
1674         }
1675 
1676         return orig_p;
1677 }
1678 
1679 /*
1680  * Unregister a kprobe without a scheduler synchronization.
1681  */
1682 static int __unregister_kprobe_top(struct kprobe *p)
1683 {
1684         struct kprobe *ap, *list_p;
1685 
1686         /* Disable kprobe. This will disarm it if needed. */
1687         ap = __disable_kprobe(p);
1688         if (IS_ERR(ap))
1689                 return PTR_ERR(ap);
1690 
1691         if (ap == p)
1692                 /*
1693                  * This probe is an independent(and non-optimized) kprobe
1694                  * (not an aggrprobe). Remove from the hash list.
1695                  */
1696                 goto disarmed;
1697 
1698         /* Following process expects this probe is an aggrprobe */
1699         WARN_ON(!kprobe_aggrprobe(ap));
1700 
1701         if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1702                 /*
1703                  * !disarmed could be happen if the probe is under delayed
1704                  * unoptimizing.
1705                  */
1706                 goto disarmed;
1707         else {
1708                 /* If disabling probe has special handlers, update aggrprobe */
1709                 if (p->break_handler && !kprobe_gone(p))
1710                         ap->break_handler = NULL;
1711                 if (p->post_handler && !kprobe_gone(p)) {
1712                         list_for_each_entry_rcu(list_p, &ap->list, list) {
1713                                 if ((list_p != p) && (list_p->post_handler))
1714                                         goto noclean;
1715                         }
1716                         ap->post_handler = NULL;
1717                 }
1718 noclean:
1719                 /*
1720                  * Remove from the aggrprobe: this path will do nothing in
1721                  * __unregister_kprobe_bottom().
1722                  */
1723                 list_del_rcu(&p->list);
1724                 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1725                         /*
1726                          * Try to optimize this probe again, because post
1727                          * handler may have been changed.
1728                          */
1729                         optimize_kprobe(ap);
1730         }
1731         return 0;
1732 
1733 disarmed:
1734         BUG_ON(!kprobe_disarmed(ap));
1735         hlist_del_rcu(&ap->hlist);
1736         return 0;
1737 }
1738 
1739 static void __unregister_kprobe_bottom(struct kprobe *p)
1740 {
1741         struct kprobe *ap;
1742 
1743         if (list_empty(&p->list))
1744                 /* This is an independent kprobe */
1745                 arch_remove_kprobe(p);
1746         else if (list_is_singular(&p->list)) {
1747                 /* This is the last child of an aggrprobe */
1748                 ap = list_entry(p->list.next, struct kprobe, list);
1749                 list_del(&p->list);
1750                 free_aggr_kprobe(ap);
1751         }
1752         /* Otherwise, do nothing. */
1753 }
1754 
1755 int register_kprobes(struct kprobe **kps, int num)
1756 {
1757         int i, ret = 0;
1758 
1759         if (num <= 0)
1760                 return -EINVAL;
1761         for (i = 0; i < num; i++) {
1762                 ret = register_kprobe(kps[i]);
1763                 if (ret < 0) {
1764                         if (i > 0)
1765                                 unregister_kprobes(kps, i);
1766                         break;
1767                 }
1768         }
1769         return ret;
1770 }
1771 EXPORT_SYMBOL_GPL(register_kprobes);
1772 
1773 void unregister_kprobe(struct kprobe *p)
1774 {
1775         unregister_kprobes(&p, 1);
1776 }
1777 EXPORT_SYMBOL_GPL(unregister_kprobe);
1778 
1779 void unregister_kprobes(struct kprobe **kps, int num)
1780 {
1781         int i;
1782 
1783         if (num <= 0)
1784                 return;
1785         mutex_lock(&kprobe_mutex);
1786         for (i = 0; i < num; i++)
1787                 if (__unregister_kprobe_top(kps[i]) < 0)
1788                         kps[i]->addr = NULL;
1789         mutex_unlock(&kprobe_mutex);
1790 
1791         synchronize_sched();
1792         for (i = 0; i < num; i++)
1793                 if (kps[i]->addr)
1794                         __unregister_kprobe_bottom(kps[i]);
1795 }
1796 EXPORT_SYMBOL_GPL(unregister_kprobes);
1797 
1798 int __weak kprobe_exceptions_notify(struct notifier_block *self,
1799                                         unsigned long val, void *data)
1800 {
1801         return NOTIFY_DONE;
1802 }
1803 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
1804 
1805 static struct notifier_block kprobe_exceptions_nb = {
1806         .notifier_call = kprobe_exceptions_notify,
1807         .priority = 0x7fffffff /* we need to be notified first */
1808 };
1809 
1810 unsigned long __weak arch_deref_entry_point(void *entry)
1811 {
1812         return (unsigned long)entry;
1813 }
1814 
1815 #if 0
1816 int register_jprobes(struct jprobe **jps, int num)
1817 {
1818         int ret = 0, i;
1819 
1820         if (num <= 0)
1821                 return -EINVAL;
1822 
1823         for (i = 0; i < num; i++) {
1824                 ret = register_jprobe(jps[i]);
1825 
1826                 if (ret < 0) {
1827                         if (i > 0)
1828                                 unregister_jprobes(jps, i);
1829                         break;
1830                 }
1831         }
1832 
1833         return ret;
1834 }
1835 EXPORT_SYMBOL_GPL(register_jprobes);
1836 
1837 int register_jprobe(struct jprobe *jp)
1838 {
1839         unsigned long addr, offset;
1840         struct kprobe *kp = &jp->kp;
1841 
1842         /*
1843          * Verify probepoint as well as the jprobe handler are
1844          * valid function entry points.
1845          */
1846         addr = arch_deref_entry_point(jp->entry);
1847 
1848         if (kallsyms_lookup_size_offset(addr, NULL, &offset) && offset == 0 &&
1849             kprobe_on_func_entry(kp->addr, kp->symbol_name, kp->offset)) {
1850                 kp->pre_handler = setjmp_pre_handler;
1851                 kp->break_handler = longjmp_break_handler;
1852                 return register_kprobe(kp);
1853         }
1854 
1855         return -EINVAL;
1856 }
1857 EXPORT_SYMBOL_GPL(register_jprobe);
1858 
1859 void unregister_jprobe(struct jprobe *jp)
1860 {
1861         unregister_jprobes(&jp, 1);
1862 }
1863 EXPORT_SYMBOL_GPL(unregister_jprobe);
1864 
1865 void unregister_jprobes(struct jprobe **jps, int num)
1866 {
1867         int i;
1868 
1869         if (num <= 0)
1870                 return;
1871         mutex_lock(&kprobe_mutex);
1872         for (i = 0; i < num; i++)
1873                 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1874                         jps[i]->kp.addr = NULL;
1875         mutex_unlock(&kprobe_mutex);
1876 
1877         synchronize_sched();
1878         for (i = 0; i < num; i++) {
1879                 if (jps[i]->kp.addr)
1880                         __unregister_kprobe_bottom(&jps[i]->kp);
1881         }
1882 }
1883 EXPORT_SYMBOL_GPL(unregister_jprobes);
1884 #endif
1885 
1886 #ifdef CONFIG_KRETPROBES
1887 /*
1888  * This kprobe pre_handler is registered with every kretprobe. When probe
1889  * hits it will set up the return probe.
1890  */
1891 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
1892 {
1893         struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1894         unsigned long hash, flags = 0;
1895         struct kretprobe_instance *ri;
1896 
1897         /*
1898          * To avoid deadlocks, prohibit return probing in NMI contexts,
1899          * just skip the probe and increase the (inexact) 'nmissed'
1900          * statistical counter, so that the user is informed that
1901          * something happened:
1902          */
1903         if (unlikely(in_nmi())) {
1904                 rp->nmissed++;
1905                 return 0;
1906         }
1907 
1908         /* TODO: consider to only swap the RA after the last pre_handler fired */
1909         hash = hash_ptr(current, KPROBE_HASH_BITS);
1910         raw_spin_lock_irqsave(&rp->lock, flags);
1911         if (!hlist_empty(&rp->free_instances)) {
1912                 ri = hlist_entry(rp->free_instances.first,
1913                                 struct kretprobe_instance, hlist);
1914                 hlist_del(&ri->hlist);
1915                 raw_spin_unlock_irqrestore(&rp->lock, flags);
1916 
1917                 ri->rp = rp;
1918                 ri->task = current;
1919 
1920                 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1921                         raw_spin_lock_irqsave(&rp->lock, flags);
1922                         hlist_add_head(&ri->hlist, &rp->free_instances);
1923                         raw_spin_unlock_irqrestore(&rp->lock, flags);
1924                         return 0;
1925                 }
1926 
1927                 arch_prepare_kretprobe(ri, regs);
1928 
1929                 /* XXX(hch): why is there no hlist_move_head? */
1930                 INIT_HLIST_NODE(&ri->hlist);
1931                 kretprobe_table_lock(hash, &flags);
1932                 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1933                 kretprobe_table_unlock(hash, &flags);
1934         } else {
1935                 rp->nmissed++;
1936                 raw_spin_unlock_irqrestore(&rp->lock, flags);
1937         }
1938         return 0;
1939 }
1940 NOKPROBE_SYMBOL(pre_handler_kretprobe);
1941 
1942 bool __weak arch_kprobe_on_func_entry(unsigned long offset)
1943 {
1944         return !offset;
1945 }
1946 
1947 bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
1948 {
1949         kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset);
1950 
1951         if (IS_ERR(kp_addr))
1952                 return false;
1953 
1954         if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) ||
1955                                                 !arch_kprobe_on_func_entry(offset))
1956                 return false;
1957 
1958         return true;
1959 }
1960 
1961 int register_kretprobe(struct kretprobe *rp)
1962 {
1963         int ret = 0;
1964         struct kretprobe_instance *inst;
1965         int i;
1966         void *addr;
1967 
1968         if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset))
1969                 return -EINVAL;
1970 
1971         if (kretprobe_blacklist_size) {
1972                 addr = kprobe_addr(&rp->kp);
1973                 if (IS_ERR(addr))
1974                         return PTR_ERR(addr);
1975 
1976                 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1977                         if (kretprobe_blacklist[i].addr == addr)
1978                                 return -EINVAL;
1979                 }
1980         }
1981 
1982         rp->kp.pre_handler = pre_handler_kretprobe;
1983         rp->kp.post_handler = NULL;
1984         rp->kp.fault_handler = NULL;
1985         rp->kp.break_handler = NULL;
1986 
1987         /* Pre-allocate memory for max kretprobe instances */
1988         if (rp->maxactive <= 0) {
1989 #ifdef CONFIG_PREEMPT
1990                 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1991 #else
1992                 rp->maxactive = num_possible_cpus();
1993 #endif
1994         }
1995         raw_spin_lock_init(&rp->lock);
1996         INIT_HLIST_HEAD(&rp->free_instances);
1997         for (i = 0; i < rp->maxactive; i++) {
1998                 inst = kmalloc(sizeof(struct kretprobe_instance) +
1999                                rp->data_size, GFP_KERNEL);
2000                 if (inst == NULL) {
2001                         free_rp_inst(rp);
2002                         return -ENOMEM;
2003                 }
2004                 INIT_HLIST_NODE(&inst->hlist);
2005                 hlist_add_head(&inst->hlist, &rp->free_instances);
2006         }
2007 
2008         rp->nmissed = 0;
2009         /* Establish function entry probe point */
2010         ret = register_kprobe(&rp->kp);
2011         if (ret != 0)
2012                 free_rp_inst(rp);
2013         return ret;
2014 }
2015 EXPORT_SYMBOL_GPL(register_kretprobe);
2016 
2017 int register_kretprobes(struct kretprobe **rps, int num)
2018 {
2019         int ret = 0, i;
2020 
2021         if (num <= 0)
2022                 return -EINVAL;
2023         for (i = 0; i < num; i++) {
2024                 ret = register_kretprobe(rps[i]);
2025                 if (ret < 0) {
2026                         if (i > 0)
2027                                 unregister_kretprobes(rps, i);
2028                         break;
2029                 }
2030         }
2031         return ret;
2032 }
2033 EXPORT_SYMBOL_GPL(register_kretprobes);
2034 
2035 void unregister_kretprobe(struct kretprobe *rp)
2036 {
2037         unregister_kretprobes(&rp, 1);
2038 }
2039 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2040 
2041 void unregister_kretprobes(struct kretprobe **rps, int num)
2042 {
2043         int i;
2044 
2045         if (num <= 0)
2046                 return;
2047         mutex_lock(&kprobe_mutex);
2048         for (i = 0; i < num; i++)
2049                 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
2050                         rps[i]->kp.addr = NULL;
2051         mutex_unlock(&kprobe_mutex);
2052 
2053         synchronize_sched();
2054         for (i = 0; i < num; i++) {
2055                 if (rps[i]->kp.addr) {
2056                         __unregister_kprobe_bottom(&rps[i]->kp);
2057                         cleanup_rp_inst(rps[i]);
2058                 }
2059         }
2060 }
2061 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2062 
2063 #else /* CONFIG_KRETPROBES */
2064 int register_kretprobe(struct kretprobe *rp)
2065 {
2066         return -ENOSYS;
2067 }
2068 EXPORT_SYMBOL_GPL(register_kretprobe);
2069 
2070 int register_kretprobes(struct kretprobe **rps, int num)
2071 {
2072         return -ENOSYS;
2073 }
2074 EXPORT_SYMBOL_GPL(register_kretprobes);
2075 
2076 void unregister_kretprobe(struct kretprobe *rp)
2077 {
2078 }
2079 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2080 
2081 void unregister_kretprobes(struct kretprobe **rps, int num)
2082 {
2083 }
2084 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2085 
2086 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2087 {
2088         return 0;
2089 }
2090 NOKPROBE_SYMBOL(pre_handler_kretprobe);
2091 
2092 #endif /* CONFIG_KRETPROBES */
2093 
2094 /* Set the kprobe gone and remove its instruction buffer. */
2095 static void kill_kprobe(struct kprobe *p)
2096 {
2097         struct kprobe *kp;
2098 
2099         p->flags |= KPROBE_FLAG_GONE;
2100         if (kprobe_aggrprobe(p)) {
2101                 /*
2102                  * If this is an aggr_kprobe, we have to list all the
2103                  * chained probes and mark them GONE.
2104                  */
2105                 list_for_each_entry_rcu(kp, &p->list, list)
2106                         kp->flags |= KPROBE_FLAG_GONE;
2107                 p->post_handler = NULL;
2108                 p->break_handler = NULL;
2109                 kill_optimized_kprobe(p);
2110         }
2111         /*
2112          * Here, we can remove insn_slot safely, because no thread calls
2113          * the original probed function (which will be freed soon) any more.
2114          */
2115         arch_remove_kprobe(p);
2116 }
2117 
2118 /* Disable one kprobe */
2119 int disable_kprobe(struct kprobe *kp)
2120 {
2121         int ret = 0;
2122         struct kprobe *p;
2123 
2124         mutex_lock(&kprobe_mutex);
2125 
2126         /* Disable this kprobe */
2127         p = __disable_kprobe(kp);
2128         if (IS_ERR(p))
2129                 ret = PTR_ERR(p);
2130 
2131         mutex_unlock(&kprobe_mutex);
2132         return ret;
2133 }
2134 EXPORT_SYMBOL_GPL(disable_kprobe);
2135 
2136 /* Enable one kprobe */
2137 int enable_kprobe(struct kprobe *kp)
2138 {
2139         int ret = 0;
2140         struct kprobe *p;
2141 
2142         mutex_lock(&kprobe_mutex);
2143 
2144         /* Check whether specified probe is valid. */
2145         p = __get_valid_kprobe(kp);
2146         if (unlikely(p == NULL)) {
2147                 ret = -EINVAL;
2148                 goto out;
2149         }
2150 
2151         if (kprobe_gone(kp)) {
2152                 /* This kprobe has gone, we couldn't enable it. */
2153                 ret = -EINVAL;
2154                 goto out;
2155         }
2156 
2157         if (p != kp)
2158                 kp->flags &= ~KPROBE_FLAG_DISABLED;
2159 
2160         if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2161                 p->flags &= ~KPROBE_FLAG_DISABLED;
2162                 ret = arm_kprobe(p);
2163                 if (ret)
2164                         p->flags |= KPROBE_FLAG_DISABLED;
2165         }
2166 out:
2167         mutex_unlock(&kprobe_mutex);
2168         return ret;
2169 }
2170 EXPORT_SYMBOL_GPL(enable_kprobe);
2171 
2172 void dump_kprobe(struct kprobe *kp)
2173 {
2174         printk(KERN_WARNING "Dumping kprobe:\n");
2175         printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
2176                kp->symbol_name, kp->addr, kp->offset);
2177 }
2178 NOKPROBE_SYMBOL(dump_kprobe);
2179 
2180 /*
2181  * Lookup and populate the kprobe_blacklist.
2182  *
2183  * Unlike the kretprobe blacklist, we'll need to determine
2184  * the range of addresses that belong to the said functions,
2185  * since a kprobe need not necessarily be at the beginning
2186  * of a function.
2187  */
2188 static int __init populate_kprobe_blacklist(unsigned long *start,
2189                                              unsigned long *end)
2190 {
2191         unsigned long *iter;
2192         struct kprobe_blacklist_entry *ent;
2193         unsigned long entry, offset = 0, size = 0;
2194 
2195         for (iter = start; iter < end; iter++) {
2196                 entry = arch_deref_entry_point((void *)*iter);
2197 
2198                 if (!kernel_text_address(entry) ||
2199                     !kallsyms_lookup_size_offset(entry, &size, &offset)) {
2200                         pr_err("Failed to find blacklist at %p\n",
2201                                 (void *)entry);
2202                         continue;
2203                 }
2204 
2205                 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
2206                 if (!ent)
2207                         return -ENOMEM;
2208                 ent->start_addr = entry;
2209                 ent->end_addr = entry + size;
2210                 INIT_LIST_HEAD(&ent->list);
2211                 list_add_tail(&ent->list, &kprobe_blacklist);
2212         }
2213         return 0;
2214 }
2215 
2216 /* Module notifier call back, checking kprobes on the module */
2217 static int kprobes_module_callback(struct notifier_block *nb,
2218                                    unsigned long val, void *data)
2219 {
2220         struct module *mod = data;
2221         struct hlist_head *head;
2222         struct kprobe *p;
2223         unsigned int i;
2224         int checkcore = (val == MODULE_STATE_GOING);
2225 
2226         if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
2227                 return NOTIFY_DONE;
2228 
2229         /*
2230          * When MODULE_STATE_GOING was notified, both of module .text and
2231          * .init.text sections would be freed. When MODULE_STATE_LIVE was
2232          * notified, only .init.text section would be freed. We need to
2233          * disable kprobes which have been inserted in the sections.
2234          */
2235         mutex_lock(&kprobe_mutex);
2236         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2237                 head = &kprobe_table[i];
2238                 hlist_for_each_entry_rcu(p, head, hlist)
2239                         if (within_module_init((unsigned long)p->addr, mod) ||
2240                             (checkcore &&
2241                              within_module_core((unsigned long)p->addr, mod))) {
2242                                 /*
2243                                  * The vaddr this probe is installed will soon
2244                                  * be vfreed buy not synced to disk. Hence,
2245                                  * disarming the breakpoint isn't needed.
2246                                  *
2247                                  * Note, this will also move any optimized probes
2248                                  * that are pending to be removed from their
2249                                  * corresponding lists to the freeing_list and
2250                                  * will not be touched by the delayed
2251                                  * kprobe_optimizer work handler.
2252                                  */
2253                                 kill_kprobe(p);
2254                         }
2255         }
2256         mutex_unlock(&kprobe_mutex);
2257         return NOTIFY_DONE;
2258 }
2259 
2260 static struct notifier_block kprobe_module_nb = {
2261         .notifier_call = kprobes_module_callback,
2262         .priority = 0
2263 };
2264 
2265 /* Markers of _kprobe_blacklist section */
2266 extern unsigned long __start_kprobe_blacklist[];
2267 extern unsigned long __stop_kprobe_blacklist[];
2268 
2269 static int __init init_kprobes(void)
2270 {
2271         int i, err = 0;
2272 
2273         /* FIXME allocate the probe table, currently defined statically */
2274         /* initialize all list heads */
2275         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2276                 INIT_HLIST_HEAD(&kprobe_table[i]);
2277                 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
2278                 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
2279         }
2280 
2281         err = populate_kprobe_blacklist(__start_kprobe_blacklist,
2282                                         __stop_kprobe_blacklist);
2283         if (err) {
2284                 pr_err("kprobes: failed to populate blacklist: %d\n", err);
2285                 pr_err("Please take care of using kprobes.\n");
2286         }
2287 
2288         if (kretprobe_blacklist_size) {
2289                 /* lookup the function address from its name */
2290                 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2291                         kretprobe_blacklist[i].addr =
2292                                 kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
2293                         if (!kretprobe_blacklist[i].addr)
2294                                 printk("kretprobe: lookup failed: %s\n",
2295                                        kretprobe_blacklist[i].name);
2296                 }
2297         }
2298 
2299 #if defined(CONFIG_OPTPROBES)
2300 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2301         /* Init kprobe_optinsn_slots */
2302         kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2303 #endif
2304         /* By default, kprobes can be optimized */
2305         kprobes_allow_optimization = true;
2306 #endif
2307 
2308         /* By default, kprobes are armed */
2309         kprobes_all_disarmed = false;
2310 
2311         err = arch_init_kprobes();
2312         if (!err)
2313                 err = register_die_notifier(&kprobe_exceptions_nb);
2314         if (!err)
2315                 err = register_module_notifier(&kprobe_module_nb);
2316 
2317         kprobes_initialized = (err == 0);
2318 
2319         if (!err)
2320                 init_test_probes();
2321         return err;
2322 }
2323 
2324 #ifdef CONFIG_DEBUG_FS
2325 static void report_probe(struct seq_file *pi, struct kprobe *p,
2326                 const char *sym, int offset, char *modname, struct kprobe *pp)
2327 {
2328         char *kprobe_type;
2329 
2330         if (p->pre_handler == pre_handler_kretprobe)
2331                 kprobe_type = "r";
2332         else if (p->pre_handler == setjmp_pre_handler)
2333                 kprobe_type = "j";
2334         else
2335                 kprobe_type = "k";
2336 
2337         if (sym)
2338                 seq_printf(pi, "%p  %s  %s+0x%x  %s ",
2339                         p->addr, kprobe_type, sym, offset,
2340                         (modname ? modname : " "));
2341         else
2342                 seq_printf(pi, "%p  %s  %p ",
2343                         p->addr, kprobe_type, p->addr);
2344 
2345         if (!pp)
2346                 pp = p;
2347         seq_printf(pi, "%s%s%s%s\n",
2348                 (kprobe_gone(p) ? "[GONE]" : ""),
2349                 ((kprobe_disabled(p) && !kprobe_gone(p)) ?  "[DISABLED]" : ""),
2350                 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
2351                 (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
2352 }
2353 
2354 static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2355 {
2356         return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2357 }
2358 
2359 static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2360 {
2361         (*pos)++;
2362         if (*pos >= KPROBE_TABLE_SIZE)
2363                 return NULL;
2364         return pos;
2365 }
2366 
2367 static void kprobe_seq_stop(struct seq_file *f, void *v)
2368 {
2369         /* Nothing to do */
2370 }
2371 
2372 static int show_kprobe_addr(struct seq_file *pi, void *v)
2373 {
2374         struct hlist_head *head;
2375         struct kprobe *p, *kp;
2376         const char *sym = NULL;
2377         unsigned int i = *(loff_t *) v;
2378         unsigned long offset = 0;
2379         char *modname, namebuf[KSYM_NAME_LEN];
2380 
2381         head = &kprobe_table[i];
2382         preempt_disable();
2383         hlist_for_each_entry_rcu(p, head, hlist) {
2384                 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2385                                         &offset, &modname, namebuf);
2386                 if (kprobe_aggrprobe(p)) {
2387                         list_for_each_entry_rcu(kp, &p->list, list)
2388                                 report_probe(pi, kp, sym, offset, modname, p);
2389                 } else
2390                         report_probe(pi, p, sym, offset, modname, NULL);
2391         }
2392         preempt_enable();
2393         return 0;
2394 }
2395 
2396 static const struct seq_operations kprobes_seq_ops = {
2397         .start = kprobe_seq_start,
2398         .next  = kprobe_seq_next,
2399         .stop  = kprobe_seq_stop,
2400         .show  = show_kprobe_addr
2401 };
2402 
2403 static int kprobes_open(struct inode *inode, struct file *filp)
2404 {
2405         return seq_open(filp, &kprobes_seq_ops);
2406 }
2407 
2408 static const struct file_operations debugfs_kprobes_operations = {
2409         .open           = kprobes_open,
2410         .read           = seq_read,
2411         .llseek         = seq_lseek,
2412         .release        = seq_release,
2413 };
2414 
2415 /* kprobes/blacklist -- shows which functions can not be probed */
2416 static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
2417 {
2418         return seq_list_start(&kprobe_blacklist, *pos);
2419 }
2420 
2421 static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
2422 {
2423         return seq_list_next(v, &kprobe_blacklist, pos);
2424 }
2425 
2426 static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
2427 {
2428         struct kprobe_blacklist_entry *ent =
2429                 list_entry(v, struct kprobe_blacklist_entry, list);
2430 
2431         seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
2432                    (void *)ent->end_addr, (void *)ent->start_addr);
2433         return 0;
2434 }
2435 
2436 static const struct seq_operations kprobe_blacklist_seq_ops = {
2437         .start = kprobe_blacklist_seq_start,
2438         .next  = kprobe_blacklist_seq_next,
2439         .stop  = kprobe_seq_stop,       /* Reuse void function */
2440         .show  = kprobe_blacklist_seq_show,
2441 };
2442 
2443 static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
2444 {
2445         return seq_open(filp, &kprobe_blacklist_seq_ops);
2446 }
2447 
2448 static const struct file_operations debugfs_kprobe_blacklist_ops = {
2449         .open           = kprobe_blacklist_open,
2450         .read           = seq_read,
2451         .llseek         = seq_lseek,
2452         .release        = seq_release,
2453 };
2454 
2455 static int arm_all_kprobes(void)
2456 {
2457         struct hlist_head *head;
2458         struct kprobe *p;
2459         unsigned int i, total = 0, errors = 0;
2460         int err, ret = 0;
2461 
2462         mutex_lock(&kprobe_mutex);
2463 
2464         /* If kprobes are armed, just return */
2465         if (!kprobes_all_disarmed)
2466                 goto already_enabled;
2467 
2468         /*
2469          * optimize_kprobe() called by arm_kprobe() checks
2470          * kprobes_all_disarmed, so set kprobes_all_disarmed before
2471          * arm_kprobe.
2472          */
2473         kprobes_all_disarmed = false;
2474         /* Arming kprobes doesn't optimize kprobe itself */
2475         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2476                 head = &kprobe_table[i];
2477                 /* Arm all kprobes on a best-effort basis */
2478                 hlist_for_each_entry_rcu(p, head, hlist) {
2479                         if (!kprobe_disabled(p)) {
2480                                 err = arm_kprobe(p);
2481                                 if (err)  {
2482                                         errors++;
2483                                         ret = err;
2484                                 }
2485                                 total++;
2486                         }
2487                 }
2488         }
2489 
2490         if (errors)
2491                 pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n",
2492                         errors, total);
2493         else
2494                 pr_info("Kprobes globally enabled\n");
2495 
2496 already_enabled:
2497         mutex_unlock(&kprobe_mutex);
2498         return ret;
2499 }
2500 
2501 static int disarm_all_kprobes(void)
2502 {
2503         struct hlist_head *head;
2504         struct kprobe *p;
2505         unsigned int i, total = 0, errors = 0;
2506         int err, ret = 0;
2507 
2508         mutex_lock(&kprobe_mutex);
2509 
2510         /* If kprobes are already disarmed, just return */
2511         if (kprobes_all_disarmed) {
2512                 mutex_unlock(&kprobe_mutex);
2513                 return 0;
2514         }
2515 
2516         kprobes_all_disarmed = true;
2517 
2518         for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2519                 head = &kprobe_table[i];
2520                 /* Disarm all kprobes on a best-effort basis */
2521                 hlist_for_each_entry_rcu(p, head, hlist) {
2522                         if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
2523                                 err = disarm_kprobe(p, false);
2524                                 if (err) {
2525                                         errors++;
2526                                         ret = err;
2527                                 }
2528                                 total++;
2529                         }
2530                 }
2531         }
2532 
2533         if (errors)
2534                 pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n",
2535                         errors, total);
2536         else
2537                 pr_info("Kprobes globally disabled\n");
2538 
2539         mutex_unlock(&kprobe_mutex);
2540 
2541         /* Wait for disarming all kprobes by optimizer */
2542         wait_for_kprobe_optimizer();
2543 
2544         return ret;
2545 }
2546 
2547 /*
2548  * XXX: The debugfs bool file interface doesn't allow for callbacks
2549  * when the bool state is switched. We can reuse that facility when
2550  * available
2551  */
2552 static ssize_t read_enabled_file_bool(struct file *file,
2553                char __user *user_buf, size_t count, loff_t *ppos)
2554 {
2555         char buf[3];
2556 
2557         if (!kprobes_all_disarmed)
2558                 buf[0] = '1';
2559         else
2560                 buf[0] = '';
2561         buf[1] = '\n';
2562         buf[2] = 0x00;
2563         return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2564 }
2565 
2566 static ssize_t write_enabled_file_bool(struct file *file,
2567                const char __user *user_buf, size_t count, loff_t *ppos)
2568 {
2569         char buf[32];
2570         size_t buf_size;
2571         int ret = 0;
2572 
2573         buf_size = min(count, (sizeof(buf)-1));
2574         if (copy_from_user(buf, user_buf, buf_size))
2575                 return -EFAULT;
2576 
2577         buf[buf_size] = '\0';
2578         switch (buf[0]) {
2579         case 'y':
2580         case 'Y':
2581         case '1':
2582                 ret = arm_all_kprobes();
2583                 break;
2584         case 'n':
2585         case 'N':
2586         case '':
2587                 ret = disarm_all_kprobes();
2588                 break;
2589         default:
2590                 return -EINVAL;
2591         }
2592 
2593         if (ret)
2594                 return ret;
2595 
2596         return count;
2597 }
2598 
2599 static const struct file_operations fops_kp = {
2600         .read =         read_enabled_file_bool,
2601         .write =        write_enabled_file_bool,
2602         .llseek =       default_llseek,
2603 };
2604 
2605 static int __init debugfs_kprobe_init(void)
2606 {
2607         struct dentry *dir, *file;
2608         unsigned int value = 1;
2609 
2610         dir = debugfs_create_dir("kprobes", NULL);
2611         if (!dir)
2612                 return -ENOMEM;
2613 
2614         file = debugfs_create_file("list", 0444, dir, NULL,
2615                                 &debugfs_kprobes_operations);
2616         if (!file)
2617                 goto error;
2618 
2619         file = debugfs_create_file("enabled", 0600, dir,
2620                                         &value, &fops_kp);
2621         if (!file)
2622                 goto error;
2623 
2624         file = debugfs_create_file("blacklist", 0444, dir, NULL,
2625                                 &debugfs_kprobe_blacklist_ops);
2626         if (!file)
2627                 goto error;
2628 
2629         return 0;
2630 
2631 error:
2632         debugfs_remove(dir);
2633         return -ENOMEM;
2634 }
2635 
2636 late_initcall(debugfs_kprobe_init);
2637 #endif /* CONFIG_DEBUG_FS */
2638 
2639 module_init(init_kprobes);
2640 
2641 /* defined in arch/.../kernel/kprobes.c */
2642 EXPORT_SYMBOL_GPL(jprobe_return);
2643 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp