2 * Kernel Probes (KProbes)
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.
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.
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.
19 * Copyright (C) IBM Corporation, 2002, 2004
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
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.
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>
52 #include <asm/sections.h>
53 #include <asm/cacheflush.h>
54 #include <asm/errno.h>
55 #include <linux/uaccess.h>
57 #define KPROBE_HASH_BITS 6
58 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
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];
65 /* NOTE: change this value only with kprobe_mutex held */
66 static bool kprobes_all_disarmed;
68 /* This protects kprobe_table and optimizing_list */
69 static DEFINE_MUTEX(kprobe_mutex);
70 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
72 raw_spinlock_t lock ____cacheline_aligned_in_smp;
73 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
75 kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
76 unsigned int __unused)
78 return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
81 static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
83 return &(kretprobe_table_locks[hash].lock);
86 /* Blacklist -- list of struct kprobe_blacklist_entry */
87 static LIST_HEAD(kprobe_blacklist);
89 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
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
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;
105 #define KPROBE_INSN_PAGE_SIZE(slots) \
106 (offsetof(struct kprobe_insn_page, slot_used) + \
107 (sizeof(char) * (slots)))
109 static int slots_per_page(struct kprobe_insn_cache *c)
111 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
114 enum kprobe_slot_state {
120 void __weak *alloc_insn_page(void)
122 return module_alloc(PAGE_SIZE);
125 void __weak free_insn_page(void *page)
127 module_memfree(page);
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,
138 static int collect_garbage_slots(struct kprobe_insn_cache *c);
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.
144 kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
146 struct kprobe_insn_page *kip;
147 kprobe_opcode_t *slot = NULL;
149 /* Since the slot array is not protected by rcu, we need a mutex */
150 mutex_lock(&c->mutex);
153 list_for_each_entry_rcu(kip, &c->pages, list) {
154 if (kip->nused < slots_per_page(c)) {
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;
160 slot = kip->insns + (i * c->insn_size);
165 /* kip->nused is broken. Fix it. */
166 kip->nused = slots_per_page(c);
172 /* If there are any garbage slots, collect it and try again. */
173 if (c->nr_garbage && collect_garbage_slots(c) == 0)
176 /* All out of space. Need to allocate a new page. */
177 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
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.
186 kip->insns = c->alloc();
191 INIT_LIST_HEAD(&kip->list);
192 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
193 kip->slot_used[0] = SLOT_USED;
197 list_add_rcu(&kip->list, &c->pages);
200 mutex_unlock(&c->mutex);
204 /* Return 1 if all garbages are collected, otherwise 0. */
205 static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
207 kip->slot_used[idx] = SLOT_CLEAN;
209 if (kip->nused == 0) {
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.
216 if (!list_is_singular(&kip->list)) {
217 list_del_rcu(&kip->list);
219 kip->cache->free(kip->insns);
227 static int collect_garbage_slots(struct kprobe_insn_cache *c)
229 struct kprobe_insn_page *kip, *next;
231 /* Ensure no-one is interrupted on the garbages */
234 list_for_each_entry_safe(kip, next, &c->pages, list) {
236 if (kip->ngarbage == 0)
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))
248 void __free_insn_slot(struct kprobe_insn_cache *c,
249 kprobe_opcode_t *slot, int dirty)
251 struct kprobe_insn_page *kip;
254 mutex_lock(&c->mutex);
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))
262 /* Could not find this slot. */
267 /* Mark and sweep: this may sleep */
269 /* Check double free */
270 WARN_ON(kip->slot_used[idx] != SLOT_USED);
272 kip->slot_used[idx] = SLOT_DIRTY;
274 if (++c->nr_garbage > slots_per_page(c))
275 collect_garbage_slots(c);
277 collect_one_slot(kip, idx);
280 mutex_unlock(&c->mutex);
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.
288 bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
290 struct kprobe_insn_page *kip;
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) {
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 */
319 /* We have preemption disabled.. so it is safe to use __ versions */
320 static inline void set_kprobe_instance(struct kprobe *kp)
322 __this_cpu_write(kprobe_instance, kp);
325 static inline void reset_kprobe_instance(void)
327 __this_cpu_write(kprobe_instance, NULL);
331 * This routine is called either:
332 * - under the kprobe_mutex - during kprobe_[un]register()
334 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
336 struct kprobe *get_kprobe(void *addr)
338 struct hlist_head *head;
341 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
342 hlist_for_each_entry_rcu(p, head, hlist) {
349 NOKPROBE_SYMBOL(get_kprobe);
351 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
353 /* Return true if the kprobe is an aggregator */
354 static inline int kprobe_aggrprobe(struct kprobe *p)
356 return p->pre_handler == aggr_pre_handler;
359 /* Return true(!0) if the kprobe is unused */
360 static inline int kprobe_unused(struct kprobe *p)
362 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
363 list_empty(&p->list);
367 * Keep all fields in the kprobe consistent
369 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
371 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
372 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
375 #ifdef CONFIG_OPTPROBES
376 /* NOTE: change this value only with kprobe_mutex held */
377 static bool kprobes_allow_optimization;
380 * Call all pre_handler on the list, but ignores its return value.
381 * This must be called from arch-dep optimized caller.
383 void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
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);
392 reset_kprobe_instance();
395 NOKPROBE_SYMBOL(opt_pre_handler);
397 /* Free optimized instructions and optimized_kprobe */
398 static void free_aggr_kprobe(struct kprobe *p)
400 struct optimized_kprobe *op;
402 op = container_of(p, struct optimized_kprobe, kp);
403 arch_remove_optimized_kprobe(op);
404 arch_remove_kprobe(p);
408 /* Return true(!0) if the kprobe is ready for optimization. */
409 static inline int kprobe_optready(struct kprobe *p)
411 struct optimized_kprobe *op;
413 if (kprobe_aggrprobe(p)) {
414 op = container_of(p, struct optimized_kprobe, kp);
415 return arch_prepared_optinsn(&op->optinsn);
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)
424 struct optimized_kprobe *op;
426 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
427 if (!kprobe_aggrprobe(p))
428 return kprobe_disabled(p);
430 op = container_of(p, struct optimized_kprobe, kp);
432 return kprobe_disabled(p) && list_empty(&op->list);
435 /* Return true(!0) if the probe is queued on (un)optimizing lists */
436 static int kprobe_queued(struct kprobe *p)
438 struct optimized_kprobe *op;
440 if (kprobe_aggrprobe(p)) {
441 op = container_of(p, struct optimized_kprobe, kp);
442 if (!list_empty(&op->list))
449 * Return an optimized kprobe whose optimizing code replaces
450 * instructions including addr (exclude breakpoint).
452 static struct kprobe *get_optimized_kprobe(unsigned long addr)
455 struct kprobe *p = NULL;
456 struct optimized_kprobe *op;
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));
462 if (p && kprobe_optready(p)) {
463 op = container_of(p, struct optimized_kprobe, kp);
464 if (arch_within_optimized_kprobe(op, addr))
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);
476 static void kprobe_optimizer(struct work_struct *work);
477 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
478 #define OPTIMIZE_DELAY 5
481 * Optimize (replace a breakpoint with a jump) kprobes listed on
484 static void do_optimize_kprobes(void)
486 lockdep_assert_held(&text_mutex);
488 * The optimization/unoptimization refers online_cpus via
489 * stop_machine() and cpu-hotplug modifies online_cpus.
490 * And same time, text_mutex will be held in cpu-hotplug and here.
491 * This combination can cause a deadlock (cpu-hotplug try to lock
492 * text_mutex but stop_machine can not be done because online_cpus
494 * To avoid this deadlock, caller must have locked cpu hotplug
495 * for preventing cpu-hotplug outside of text_mutex locking.
497 lockdep_assert_cpus_held();
499 /* Optimization never be done when disarmed */
500 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
501 list_empty(&optimizing_list))
504 arch_optimize_kprobes(&optimizing_list);
508 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
509 * if need) kprobes listed on unoptimizing_list.
511 static void do_unoptimize_kprobes(void)
513 struct optimized_kprobe *op, *tmp;
515 lockdep_assert_held(&text_mutex);
516 /* See comment in do_optimize_kprobes() */
517 lockdep_assert_cpus_held();
519 /* Unoptimization must be done anytime */
520 if (list_empty(&unoptimizing_list))
523 arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
524 /* Loop free_list for disarming */
525 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
526 /* Switching from detour code to origin */
527 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
528 /* Disarm probes if marked disabled */
529 if (kprobe_disabled(&op->kp))
530 arch_disarm_kprobe(&op->kp);
531 if (kprobe_unused(&op->kp)) {
533 * Remove unused probes from hash list. After waiting
534 * for synchronization, these probes are reclaimed.
535 * (reclaiming is done by do_free_cleaned_kprobes.)
537 hlist_del_rcu(&op->kp.hlist);
539 list_del_init(&op->list);
543 /* Reclaim all kprobes on the free_list */
544 static void do_free_cleaned_kprobes(void)
546 struct optimized_kprobe *op, *tmp;
548 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
549 list_del_init(&op->list);
550 if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
552 * This must not happen, but if there is a kprobe
553 * still in use, keep it on kprobes hash list.
557 free_aggr_kprobe(&op->kp);
561 /* Start optimizer after OPTIMIZE_DELAY passed */
562 static void kick_kprobe_optimizer(void)
564 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
567 /* Kprobe jump optimizer */
568 static void kprobe_optimizer(struct work_struct *work)
570 mutex_lock(&kprobe_mutex);
572 mutex_lock(&text_mutex);
573 /* Lock modules while optimizing kprobes */
574 mutex_lock(&module_mutex);
577 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
578 * kprobes before waiting for quiesence period.
580 do_unoptimize_kprobes();
583 * Step 2: Wait for quiesence period to ensure all potentially
584 * preempted tasks to have normally scheduled. Because optprobe
585 * may modify multiple instructions, there is a chance that Nth
586 * instruction is preempted. In that case, such tasks can return
587 * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
588 * Note that on non-preemptive kernel, this is transparently converted
589 * to synchronoze_sched() to wait for all interrupts to have completed.
591 synchronize_rcu_tasks();
593 /* Step 3: Optimize kprobes after quiesence period */
594 do_optimize_kprobes();
596 /* Step 4: Free cleaned kprobes after quiesence period */
597 do_free_cleaned_kprobes();
599 mutex_unlock(&module_mutex);
600 mutex_unlock(&text_mutex);
603 /* Step 5: Kick optimizer again if needed */
604 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
605 kick_kprobe_optimizer();
607 mutex_unlock(&kprobe_mutex);
610 /* Wait for completing optimization and unoptimization */
611 void wait_for_kprobe_optimizer(void)
613 mutex_lock(&kprobe_mutex);
615 while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
616 mutex_unlock(&kprobe_mutex);
618 /* this will also make optimizing_work execute immmediately */
619 flush_delayed_work(&optimizing_work);
620 /* @optimizing_work might not have been queued yet, relax */
623 mutex_lock(&kprobe_mutex);
626 mutex_unlock(&kprobe_mutex);
629 static bool optprobe_queued_unopt(struct optimized_kprobe *op)
631 struct optimized_kprobe *_op;
633 list_for_each_entry(_op, &unoptimizing_list, list) {
641 /* Optimize kprobe if p is ready to be optimized */
642 static void optimize_kprobe(struct kprobe *p)
644 struct optimized_kprobe *op;
646 /* Check if the kprobe is disabled or not ready for optimization. */
647 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
648 (kprobe_disabled(p) || kprobes_all_disarmed))
651 /* kprobes with post_handler can not be optimized */
655 op = container_of(p, struct optimized_kprobe, kp);
657 /* Check there is no other kprobes at the optimized instructions */
658 if (arch_check_optimized_kprobe(op) < 0)
661 /* Check if it is already optimized. */
662 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) {
663 if (optprobe_queued_unopt(op)) {
664 /* This is under unoptimizing. Just dequeue the probe */
665 list_del_init(&op->list);
669 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
671 /* On unoptimizing/optimizing_list, op must have OPTIMIZED flag */
672 if (WARN_ON_ONCE(!list_empty(&op->list)))
675 list_add(&op->list, &optimizing_list);
676 kick_kprobe_optimizer();
679 /* Short cut to direct unoptimizing */
680 static void force_unoptimize_kprobe(struct optimized_kprobe *op)
682 lockdep_assert_cpus_held();
683 arch_unoptimize_kprobe(op);
684 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
685 if (kprobe_disabled(&op->kp))
686 arch_disarm_kprobe(&op->kp);
689 /* Unoptimize a kprobe if p is optimized */
690 static void unoptimize_kprobe(struct kprobe *p, bool force)
692 struct optimized_kprobe *op;
694 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
695 return; /* This is not an optprobe nor optimized */
697 op = container_of(p, struct optimized_kprobe, kp);
698 if (!kprobe_optimized(p))
701 if (!list_empty(&op->list)) {
702 if (optprobe_queued_unopt(op)) {
703 /* Queued in unoptimizing queue */
706 * Forcibly unoptimize the kprobe here, and queue it
707 * in the freeing list for release afterwards.
709 force_unoptimize_kprobe(op);
710 list_move(&op->list, &freeing_list);
713 /* Dequeue from the optimizing queue */
714 list_del_init(&op->list);
715 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
720 /* Optimized kprobe case */
722 /* Forcibly update the code: this is a special case */
723 force_unoptimize_kprobe(op);
725 list_add(&op->list, &unoptimizing_list);
726 kick_kprobe_optimizer();
730 /* Cancel unoptimizing for reusing */
731 static int reuse_unused_kprobe(struct kprobe *ap)
733 struct optimized_kprobe *op;
735 BUG_ON(!kprobe_unused(ap));
737 * Unused kprobe MUST be on the way of delayed unoptimizing (means
738 * there is still a relative jump) and disabled.
740 op = container_of(ap, struct optimized_kprobe, kp);
741 WARN_ON_ONCE(list_empty(&op->list));
742 /* Enable the probe again */
743 ap->flags &= ~KPROBE_FLAG_DISABLED;
744 /* Optimize it again (remove from op->list) */
745 if (!kprobe_optready(ap))
752 /* Remove optimized instructions */
753 static void kill_optimized_kprobe(struct kprobe *p)
755 struct optimized_kprobe *op;
757 op = container_of(p, struct optimized_kprobe, kp);
758 if (!list_empty(&op->list))
759 /* Dequeue from the (un)optimization queue */
760 list_del_init(&op->list);
761 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
763 if (kprobe_unused(p)) {
764 /* Enqueue if it is unused */
765 list_add(&op->list, &freeing_list);
767 * Remove unused probes from the hash list. After waiting
768 * for synchronization, this probe is reclaimed.
769 * (reclaiming is done by do_free_cleaned_kprobes().)
771 hlist_del_rcu(&op->kp.hlist);
774 /* Don't touch the code, because it is already freed. */
775 arch_remove_optimized_kprobe(op);
779 void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
781 if (!kprobe_ftrace(p))
782 arch_prepare_optimized_kprobe(op, p);
785 /* Try to prepare optimized instructions */
786 static void prepare_optimized_kprobe(struct kprobe *p)
788 struct optimized_kprobe *op;
790 op = container_of(p, struct optimized_kprobe, kp);
791 __prepare_optimized_kprobe(op, p);
794 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
795 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
797 struct optimized_kprobe *op;
799 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
803 INIT_LIST_HEAD(&op->list);
804 op->kp.addr = p->addr;
805 __prepare_optimized_kprobe(op, p);
810 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
813 * Prepare an optimized_kprobe and optimize it
814 * NOTE: p must be a normal registered kprobe
816 static void try_to_optimize_kprobe(struct kprobe *p)
819 struct optimized_kprobe *op;
821 /* Impossible to optimize ftrace-based kprobe */
822 if (kprobe_ftrace(p))
825 /* For preparing optimization, jump_label_text_reserved() is called */
828 mutex_lock(&text_mutex);
830 ap = alloc_aggr_kprobe(p);
834 op = container_of(ap, struct optimized_kprobe, kp);
835 if (!arch_prepared_optinsn(&op->optinsn)) {
836 /* If failed to setup optimizing, fallback to kprobe */
837 arch_remove_optimized_kprobe(op);
842 init_aggr_kprobe(ap, p);
843 optimize_kprobe(ap); /* This just kicks optimizer thread */
846 mutex_unlock(&text_mutex);
852 static void optimize_all_kprobes(void)
854 struct hlist_head *head;
858 mutex_lock(&kprobe_mutex);
859 /* If optimization is already allowed, just return */
860 if (kprobes_allow_optimization)
864 kprobes_allow_optimization = true;
865 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
866 head = &kprobe_table[i];
867 hlist_for_each_entry_rcu(p, head, hlist)
868 if (!kprobe_disabled(p))
872 printk(KERN_INFO "Kprobes globally optimized\n");
874 mutex_unlock(&kprobe_mutex);
877 static void unoptimize_all_kprobes(void)
879 struct hlist_head *head;
883 mutex_lock(&kprobe_mutex);
884 /* If optimization is already prohibited, just return */
885 if (!kprobes_allow_optimization) {
886 mutex_unlock(&kprobe_mutex);
891 kprobes_allow_optimization = false;
892 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
893 head = &kprobe_table[i];
894 hlist_for_each_entry_rcu(p, head, hlist) {
895 if (!kprobe_disabled(p))
896 unoptimize_kprobe(p, false);
900 mutex_unlock(&kprobe_mutex);
902 /* Wait for unoptimizing completion */
903 wait_for_kprobe_optimizer();
904 printk(KERN_INFO "Kprobes globally unoptimized\n");
907 static DEFINE_MUTEX(kprobe_sysctl_mutex);
908 int sysctl_kprobes_optimization;
909 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
910 void __user *buffer, size_t *length,
915 mutex_lock(&kprobe_sysctl_mutex);
916 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
917 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
919 if (sysctl_kprobes_optimization)
920 optimize_all_kprobes();
922 unoptimize_all_kprobes();
923 mutex_unlock(&kprobe_sysctl_mutex);
927 #endif /* CONFIG_SYSCTL */
929 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
930 static void __arm_kprobe(struct kprobe *p)
934 /* Check collision with other optimized kprobes */
935 _p = get_optimized_kprobe((unsigned long)p->addr);
937 /* Fallback to unoptimized kprobe */
938 unoptimize_kprobe(_p, true);
941 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
944 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
945 static void __disarm_kprobe(struct kprobe *p, bool reopt)
949 /* Try to unoptimize */
950 unoptimize_kprobe(p, kprobes_all_disarmed);
952 if (!kprobe_queued(p)) {
953 arch_disarm_kprobe(p);
954 /* If another kprobe was blocked, optimize it. */
955 _p = get_optimized_kprobe((unsigned long)p->addr);
956 if (unlikely(_p) && reopt)
959 /* TODO: reoptimize others after unoptimized this probe */
962 #else /* !CONFIG_OPTPROBES */
964 #define optimize_kprobe(p) do {} while (0)
965 #define unoptimize_kprobe(p, f) do {} while (0)
966 #define kill_optimized_kprobe(p) do {} while (0)
967 #define prepare_optimized_kprobe(p) do {} while (0)
968 #define try_to_optimize_kprobe(p) do {} while (0)
969 #define __arm_kprobe(p) arch_arm_kprobe(p)
970 #define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
971 #define kprobe_disarmed(p) kprobe_disabled(p)
972 #define wait_for_kprobe_optimizer() do {} while (0)
974 static int reuse_unused_kprobe(struct kprobe *ap)
977 * If the optimized kprobe is NOT supported, the aggr kprobe is
978 * released at the same time that the last aggregated kprobe is
980 * Thus there should be no chance to reuse unused kprobe.
982 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
986 static void free_aggr_kprobe(struct kprobe *p)
988 arch_remove_kprobe(p);
992 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
994 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
996 #endif /* CONFIG_OPTPROBES */
998 #ifdef CONFIG_KPROBES_ON_FTRACE
999 static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
1000 .func = kprobe_ftrace_handler,
1001 .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
1003 static int kprobe_ftrace_enabled;
1005 /* Must ensure p->addr is really on ftrace */
1006 static int prepare_kprobe(struct kprobe *p)
1008 if (!kprobe_ftrace(p))
1009 return arch_prepare_kprobe(p);
1011 return arch_prepare_kprobe_ftrace(p);
1014 /* Caller must lock kprobe_mutex */
1015 static int arm_kprobe_ftrace(struct kprobe *p)
1019 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
1020 (unsigned long)p->addr, 0, 0);
1022 pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
1027 if (kprobe_ftrace_enabled == 0) {
1028 ret = register_ftrace_function(&kprobe_ftrace_ops);
1030 pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
1035 kprobe_ftrace_enabled++;
1040 * Note: Since kprobe_ftrace_ops has IPMODIFY set, and ftrace requires a
1041 * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental
1042 * empty filter_hash which would undesirably trace all functions.
1044 ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0);
1048 /* Caller must lock kprobe_mutex */
1049 static int disarm_kprobe_ftrace(struct kprobe *p)
1053 if (kprobe_ftrace_enabled == 1) {
1054 ret = unregister_ftrace_function(&kprobe_ftrace_ops);
1055 if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
1059 kprobe_ftrace_enabled--;
1061 ret = ftrace_set_filter_ip(&kprobe_ftrace_ops,
1062 (unsigned long)p->addr, 1, 0);
1063 WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
1067 #else /* !CONFIG_KPROBES_ON_FTRACE */
1068 static inline int prepare_kprobe(struct kprobe *p)
1070 return arch_prepare_kprobe(p);
1073 static inline int arm_kprobe_ftrace(struct kprobe *p)
1078 static inline int disarm_kprobe_ftrace(struct kprobe *p)
1084 /* Arm a kprobe with text_mutex */
1085 static int arm_kprobe(struct kprobe *kp)
1087 if (unlikely(kprobe_ftrace(kp)))
1088 return arm_kprobe_ftrace(kp);
1091 mutex_lock(&text_mutex);
1093 mutex_unlock(&text_mutex);
1099 /* Disarm a kprobe with text_mutex */
1100 static int disarm_kprobe(struct kprobe *kp, bool reopt)
1102 if (unlikely(kprobe_ftrace(kp)))
1103 return disarm_kprobe_ftrace(kp);
1106 mutex_lock(&text_mutex);
1107 __disarm_kprobe(kp, reopt);
1108 mutex_unlock(&text_mutex);
1115 * Aggregate handlers for multiple kprobes support - these handlers
1116 * take care of invoking the individual kprobe handlers on p->list
1118 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
1122 list_for_each_entry_rcu(kp, &p->list, list) {
1123 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
1124 set_kprobe_instance(kp);
1125 if (kp->pre_handler(kp, regs))
1128 reset_kprobe_instance();
1132 NOKPROBE_SYMBOL(aggr_pre_handler);
1134 static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1135 unsigned long flags)
1139 list_for_each_entry_rcu(kp, &p->list, list) {
1140 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
1141 set_kprobe_instance(kp);
1142 kp->post_handler(kp, regs, flags);
1143 reset_kprobe_instance();
1147 NOKPROBE_SYMBOL(aggr_post_handler);
1149 static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
1152 struct kprobe *cur = __this_cpu_read(kprobe_instance);
1155 * if we faulted "during" the execution of a user specified
1156 * probe handler, invoke just that probe's fault handler
1158 if (cur && cur->fault_handler) {
1159 if (cur->fault_handler(cur, regs, trapnr))
1164 NOKPROBE_SYMBOL(aggr_fault_handler);
1166 /* Walks the list and increments nmissed count for multiprobe case */
1167 void kprobes_inc_nmissed_count(struct kprobe *p)
1170 if (!kprobe_aggrprobe(p)) {
1173 list_for_each_entry_rcu(kp, &p->list, list)
1178 NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
1180 void recycle_rp_inst(struct kretprobe_instance *ri,
1181 struct hlist_head *head)
1183 struct kretprobe *rp = ri->rp;
1185 /* remove rp inst off the rprobe_inst_table */
1186 hlist_del(&ri->hlist);
1187 INIT_HLIST_NODE(&ri->hlist);
1189 raw_spin_lock(&rp->lock);
1190 hlist_add_head(&ri->hlist, &rp->free_instances);
1191 raw_spin_unlock(&rp->lock);
1194 hlist_add_head(&ri->hlist, head);
1196 NOKPROBE_SYMBOL(recycle_rp_inst);
1198 void kretprobe_hash_lock(struct task_struct *tsk,
1199 struct hlist_head **head, unsigned long *flags)
1200 __acquires(hlist_lock)
1202 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1203 raw_spinlock_t *hlist_lock;
1205 *head = &kretprobe_inst_table[hash];
1206 hlist_lock = kretprobe_table_lock_ptr(hash);
1207 raw_spin_lock_irqsave(hlist_lock, *flags);
1209 NOKPROBE_SYMBOL(kretprobe_hash_lock);
1211 static void kretprobe_table_lock(unsigned long hash,
1212 unsigned long *flags)
1213 __acquires(hlist_lock)
1215 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1216 raw_spin_lock_irqsave(hlist_lock, *flags);
1218 NOKPROBE_SYMBOL(kretprobe_table_lock);
1220 void kretprobe_hash_unlock(struct task_struct *tsk,
1221 unsigned long *flags)
1222 __releases(hlist_lock)
1224 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1225 raw_spinlock_t *hlist_lock;
1227 hlist_lock = kretprobe_table_lock_ptr(hash);
1228 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1230 NOKPROBE_SYMBOL(kretprobe_hash_unlock);
1232 static void kretprobe_table_unlock(unsigned long hash,
1233 unsigned long *flags)
1234 __releases(hlist_lock)
1236 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1237 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1239 NOKPROBE_SYMBOL(kretprobe_table_unlock);
1241 struct kprobe kprobe_busy = {
1242 .addr = (void *) get_kprobe,
1245 void kprobe_busy_begin(void)
1247 struct kprobe_ctlblk *kcb;
1250 __this_cpu_write(current_kprobe, &kprobe_busy);
1251 kcb = get_kprobe_ctlblk();
1252 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
1255 void kprobe_busy_end(void)
1257 __this_cpu_write(current_kprobe, NULL);
1262 * This function is called from finish_task_switch when task tk becomes dead,
1263 * so that we can recycle any function-return probe instances associated
1264 * with this task. These left over instances represent probed functions
1265 * that have been called but will never return.
1267 void kprobe_flush_task(struct task_struct *tk)
1269 struct kretprobe_instance *ri;
1270 struct hlist_head *head, empty_rp;
1271 struct hlist_node *tmp;
1272 unsigned long hash, flags = 0;
1274 if (unlikely(!kprobes_initialized))
1275 /* Early boot. kretprobe_table_locks not yet initialized. */
1278 kprobe_busy_begin();
1280 INIT_HLIST_HEAD(&empty_rp);
1281 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1282 head = &kretprobe_inst_table[hash];
1283 kretprobe_table_lock(hash, &flags);
1284 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
1286 recycle_rp_inst(ri, &empty_rp);
1288 kretprobe_table_unlock(hash, &flags);
1289 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
1290 hlist_del(&ri->hlist);
1296 NOKPROBE_SYMBOL(kprobe_flush_task);
1298 static inline void free_rp_inst(struct kretprobe *rp)
1300 struct kretprobe_instance *ri;
1301 struct hlist_node *next;
1303 hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
1304 hlist_del(&ri->hlist);
1309 static void cleanup_rp_inst(struct kretprobe *rp)
1311 unsigned long flags, hash;
1312 struct kretprobe_instance *ri;
1313 struct hlist_node *next;
1314 struct hlist_head *head;
1317 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1318 kretprobe_table_lock(hash, &flags);
1319 head = &kretprobe_inst_table[hash];
1320 hlist_for_each_entry_safe(ri, next, head, hlist) {
1324 kretprobe_table_unlock(hash, &flags);
1328 NOKPROBE_SYMBOL(cleanup_rp_inst);
1330 /* Add the new probe to ap->list */
1331 static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1333 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
1335 if (p->post_handler)
1336 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
1338 list_add_rcu(&p->list, &ap->list);
1339 if (p->post_handler && !ap->post_handler)
1340 ap->post_handler = aggr_post_handler;
1346 * Fill in the required fields of the "manager kprobe". Replace the
1347 * earlier kprobe in the hlist with the manager kprobe
1349 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1351 /* Copy p's insn slot to ap */
1353 flush_insn_slot(ap);
1355 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1356 ap->pre_handler = aggr_pre_handler;
1357 ap->fault_handler = aggr_fault_handler;
1358 /* We don't care the kprobe which has gone. */
1359 if (p->post_handler && !kprobe_gone(p))
1360 ap->post_handler = aggr_post_handler;
1362 INIT_LIST_HEAD(&ap->list);
1363 INIT_HLIST_NODE(&ap->hlist);
1365 list_add_rcu(&p->list, &ap->list);
1366 hlist_replace_rcu(&p->hlist, &ap->hlist);
1370 * This is the second or subsequent kprobe at the address - handle
1373 static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
1376 struct kprobe *ap = orig_p;
1380 /* For preparing optimization, jump_label_text_reserved() is called */
1382 mutex_lock(&text_mutex);
1384 if (!kprobe_aggrprobe(orig_p)) {
1385 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1386 ap = alloc_aggr_kprobe(orig_p);
1391 init_aggr_kprobe(ap, orig_p);
1392 } else if (kprobe_unused(ap)) {
1393 /* This probe is going to die. Rescue it */
1394 ret = reuse_unused_kprobe(ap);
1399 if (kprobe_gone(ap)) {
1401 * Attempting to insert new probe at the same location that
1402 * had a probe in the module vaddr area which already
1403 * freed. So, the instruction slot has already been
1404 * released. We need a new slot for the new probe.
1406 ret = arch_prepare_kprobe(ap);
1409 * Even if fail to allocate new slot, don't need to
1410 * free aggr_probe. It will be used next time, or
1411 * freed by unregister_kprobe.
1415 /* Prepare optimized instructions if possible. */
1416 prepare_optimized_kprobe(ap);
1419 * Clear gone flag to prevent allocating new slot again, and
1420 * set disabled flag because it is not armed yet.
1422 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1423 | KPROBE_FLAG_DISABLED;
1426 /* Copy ap's insn slot to p */
1428 ret = add_new_kprobe(ap, p);
1431 mutex_unlock(&text_mutex);
1432 jump_label_unlock();
1435 if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
1436 ap->flags &= ~KPROBE_FLAG_DISABLED;
1437 if (!kprobes_all_disarmed) {
1438 /* Arm the breakpoint again. */
1439 ret = arm_kprobe(ap);
1441 ap->flags |= KPROBE_FLAG_DISABLED;
1442 list_del_rcu(&p->list);
1443 synchronize_sched();
1450 bool __weak arch_within_kprobe_blacklist(unsigned long addr)
1452 /* The __kprobes marked functions and entry code must not be probed */
1453 return addr >= (unsigned long)__kprobes_text_start &&
1454 addr < (unsigned long)__kprobes_text_end;
1457 bool within_kprobe_blacklist(unsigned long addr)
1459 struct kprobe_blacklist_entry *ent;
1461 if (arch_within_kprobe_blacklist(addr))
1464 * If there exists a kprobe_blacklist, verify and
1465 * fail any probe registration in the prohibited area
1467 list_for_each_entry(ent, &kprobe_blacklist, list) {
1468 if (addr >= ent->start_addr && addr < ent->end_addr)
1476 * If we have a symbol_name argument, look it up and add the offset field
1477 * to it. This way, we can specify a relative address to a symbol.
1478 * This returns encoded errors if it fails to look up symbol or invalid
1479 * combination of parameters.
1481 static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
1482 const char *symbol_name, unsigned int offset)
1484 if ((symbol_name && addr) || (!symbol_name && !addr))
1488 addr = kprobe_lookup_name(symbol_name, offset);
1490 return ERR_PTR(-ENOENT);
1493 addr = (kprobe_opcode_t *)(((char *)addr) + offset);
1498 return ERR_PTR(-EINVAL);
1501 static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
1503 return _kprobe_addr(p->addr, p->symbol_name, p->offset);
1506 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1507 static struct kprobe *__get_valid_kprobe(struct kprobe *p)
1509 struct kprobe *ap, *list_p;
1511 ap = get_kprobe(p->addr);
1516 list_for_each_entry_rcu(list_p, &ap->list, list)
1518 /* kprobe p is a valid probe */
1526 /* Return error if the kprobe is being re-registered */
1527 static inline int check_kprobe_rereg(struct kprobe *p)
1531 mutex_lock(&kprobe_mutex);
1532 if (__get_valid_kprobe(p))
1534 mutex_unlock(&kprobe_mutex);
1539 int __weak arch_check_ftrace_location(struct kprobe *p)
1541 unsigned long ftrace_addr;
1543 ftrace_addr = ftrace_location((unsigned long)p->addr);
1545 #ifdef CONFIG_KPROBES_ON_FTRACE
1546 /* Given address is not on the instruction boundary */
1547 if ((unsigned long)p->addr != ftrace_addr)
1549 p->flags |= KPROBE_FLAG_FTRACE;
1550 #else /* !CONFIG_KPROBES_ON_FTRACE */
1557 static int check_kprobe_address_safe(struct kprobe *p,
1558 struct module **probed_mod)
1562 ret = arch_check_ftrace_location(p);
1568 /* Ensure it is not in reserved area nor out of text */
1569 if (!kernel_text_address((unsigned long) p->addr) ||
1570 within_kprobe_blacklist((unsigned long) p->addr) ||
1571 jump_label_text_reserved(p->addr, p->addr) ||
1572 find_bug((unsigned long)p->addr)) {
1577 /* Check if are we probing a module */
1578 *probed_mod = __module_text_address((unsigned long) p->addr);
1581 * We must hold a refcount of the probed module while updating
1582 * its code to prohibit unexpected unloading.
1584 if (unlikely(!try_module_get(*probed_mod))) {
1590 * If the module freed .init.text, we couldn't insert
1593 if (within_module_init((unsigned long)p->addr, *probed_mod) &&
1594 (*probed_mod)->state != MODULE_STATE_COMING) {
1595 module_put(*probed_mod);
1602 jump_label_unlock();
1607 int register_kprobe(struct kprobe *p)
1610 struct kprobe *old_p;
1611 struct module *probed_mod;
1612 kprobe_opcode_t *addr;
1614 /* Adjust probe address from symbol */
1615 addr = kprobe_addr(p);
1617 return PTR_ERR(addr);
1620 ret = check_kprobe_rereg(p);
1624 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1625 p->flags &= KPROBE_FLAG_DISABLED;
1627 INIT_LIST_HEAD(&p->list);
1629 ret = check_kprobe_address_safe(p, &probed_mod);
1633 mutex_lock(&kprobe_mutex);
1635 old_p = get_kprobe(p->addr);
1637 /* Since this may unoptimize old_p, locking text_mutex. */
1638 ret = register_aggr_kprobe(old_p, p);
1643 /* Prevent text modification */
1644 mutex_lock(&text_mutex);
1645 ret = prepare_kprobe(p);
1646 mutex_unlock(&text_mutex);
1651 INIT_HLIST_NODE(&p->hlist);
1652 hlist_add_head_rcu(&p->hlist,
1653 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1655 if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
1656 ret = arm_kprobe(p);
1658 hlist_del_rcu(&p->hlist);
1659 synchronize_sched();
1664 /* Try to optimize kprobe */
1665 try_to_optimize_kprobe(p);
1667 mutex_unlock(&kprobe_mutex);
1670 module_put(probed_mod);
1674 EXPORT_SYMBOL_GPL(register_kprobe);
1676 /* Check if all probes on the aggrprobe are disabled */
1677 static int aggr_kprobe_disabled(struct kprobe *ap)
1681 list_for_each_entry_rcu(kp, &ap->list, list)
1682 if (!kprobe_disabled(kp))
1684 * There is an active probe on the list.
1685 * We can't disable this ap.
1692 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1693 static struct kprobe *__disable_kprobe(struct kprobe *p)
1695 struct kprobe *orig_p;
1698 /* Get an original kprobe for return */
1699 orig_p = __get_valid_kprobe(p);
1700 if (unlikely(orig_p == NULL))
1701 return ERR_PTR(-EINVAL);
1703 if (!kprobe_disabled(p)) {
1704 /* Disable probe if it is a child probe */
1706 p->flags |= KPROBE_FLAG_DISABLED;
1708 /* Try to disarm and disable this/parent probe */
1709 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1711 * If kprobes_all_disarmed is set, orig_p
1712 * should have already been disarmed, so
1713 * skip unneed disarming process.
1715 if (!kprobes_all_disarmed) {
1716 ret = disarm_kprobe(orig_p, true);
1718 p->flags &= ~KPROBE_FLAG_DISABLED;
1719 return ERR_PTR(ret);
1722 orig_p->flags |= KPROBE_FLAG_DISABLED;
1730 * Unregister a kprobe without a scheduler synchronization.
1732 static int __unregister_kprobe_top(struct kprobe *p)
1734 struct kprobe *ap, *list_p;
1736 /* Disable kprobe. This will disarm it if needed. */
1737 ap = __disable_kprobe(p);
1743 * This probe is an independent(and non-optimized) kprobe
1744 * (not an aggrprobe). Remove from the hash list.
1748 /* Following process expects this probe is an aggrprobe */
1749 WARN_ON(!kprobe_aggrprobe(ap));
1751 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1753 * !disarmed could be happen if the probe is under delayed
1758 /* If disabling probe has special handlers, update aggrprobe */
1759 if (p->post_handler && !kprobe_gone(p)) {
1760 list_for_each_entry_rcu(list_p, &ap->list, list) {
1761 if ((list_p != p) && (list_p->post_handler))
1764 ap->post_handler = NULL;
1768 * Remove from the aggrprobe: this path will do nothing in
1769 * __unregister_kprobe_bottom().
1771 list_del_rcu(&p->list);
1772 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1774 * Try to optimize this probe again, because post
1775 * handler may have been changed.
1777 optimize_kprobe(ap);
1782 BUG_ON(!kprobe_disarmed(ap));
1783 hlist_del_rcu(&ap->hlist);
1787 static void __unregister_kprobe_bottom(struct kprobe *p)
1791 if (list_empty(&p->list))
1792 /* This is an independent kprobe */
1793 arch_remove_kprobe(p);
1794 else if (list_is_singular(&p->list)) {
1795 /* This is the last child of an aggrprobe */
1796 ap = list_entry(p->list.next, struct kprobe, list);
1798 free_aggr_kprobe(ap);
1800 /* Otherwise, do nothing. */
1803 int register_kprobes(struct kprobe **kps, int num)
1809 for (i = 0; i < num; i++) {
1810 ret = register_kprobe(kps[i]);
1813 unregister_kprobes(kps, i);
1819 EXPORT_SYMBOL_GPL(register_kprobes);
1821 void unregister_kprobe(struct kprobe *p)
1823 unregister_kprobes(&p, 1);
1825 EXPORT_SYMBOL_GPL(unregister_kprobe);
1827 void unregister_kprobes(struct kprobe **kps, int num)
1833 mutex_lock(&kprobe_mutex);
1834 for (i = 0; i < num; i++)
1835 if (__unregister_kprobe_top(kps[i]) < 0)
1836 kps[i]->addr = NULL;
1837 mutex_unlock(&kprobe_mutex);
1839 synchronize_sched();
1840 for (i = 0; i < num; i++)
1842 __unregister_kprobe_bottom(kps[i]);
1844 EXPORT_SYMBOL_GPL(unregister_kprobes);
1846 int __weak kprobe_exceptions_notify(struct notifier_block *self,
1847 unsigned long val, void *data)
1851 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
1853 static struct notifier_block kprobe_exceptions_nb = {
1854 .notifier_call = kprobe_exceptions_notify,
1855 .priority = 0x7fffffff /* we need to be notified first */
1858 unsigned long __weak arch_deref_entry_point(void *entry)
1860 return (unsigned long)entry;
1863 #ifdef CONFIG_KRETPROBES
1865 * This kprobe pre_handler is registered with every kretprobe. When probe
1866 * hits it will set up the return probe.
1868 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
1870 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1871 unsigned long hash, flags = 0;
1872 struct kretprobe_instance *ri;
1875 * To avoid deadlocks, prohibit return probing in NMI contexts,
1876 * just skip the probe and increase the (inexact) 'nmissed'
1877 * statistical counter, so that the user is informed that
1878 * something happened:
1880 if (unlikely(in_nmi())) {
1885 /* TODO: consider to only swap the RA after the last pre_handler fired */
1886 hash = hash_ptr(current, KPROBE_HASH_BITS);
1887 raw_spin_lock_irqsave(&rp->lock, flags);
1888 if (!hlist_empty(&rp->free_instances)) {
1889 ri = hlist_entry(rp->free_instances.first,
1890 struct kretprobe_instance, hlist);
1891 hlist_del(&ri->hlist);
1892 raw_spin_unlock_irqrestore(&rp->lock, flags);
1897 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1898 raw_spin_lock_irqsave(&rp->lock, flags);
1899 hlist_add_head(&ri->hlist, &rp->free_instances);
1900 raw_spin_unlock_irqrestore(&rp->lock, flags);
1904 arch_prepare_kretprobe(ri, regs);
1906 /* XXX(hch): why is there no hlist_move_head? */
1907 INIT_HLIST_NODE(&ri->hlist);
1908 kretprobe_table_lock(hash, &flags);
1909 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1910 kretprobe_table_unlock(hash, &flags);
1913 raw_spin_unlock_irqrestore(&rp->lock, flags);
1917 NOKPROBE_SYMBOL(pre_handler_kretprobe);
1919 bool __weak arch_kprobe_on_func_entry(unsigned long offset)
1925 * kprobe_on_func_entry() -- check whether given address is function entry
1926 * @addr: Target address
1927 * @sym: Target symbol name
1928 * @offset: The offset from the symbol or the address
1930 * This checks whether the given @addr+@offset or @sym+@offset is on the
1931 * function entry address or not.
1932 * This returns 0 if it is the function entry, or -EINVAL if it is not.
1933 * And also it returns -ENOENT if it fails the symbol or address lookup.
1934 * Caller must pass @addr or @sym (either one must be NULL), or this
1937 int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
1939 kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset);
1941 if (IS_ERR(kp_addr))
1942 return PTR_ERR(kp_addr);
1944 if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset))
1947 if (!arch_kprobe_on_func_entry(offset))
1953 int register_kretprobe(struct kretprobe *rp)
1956 struct kretprobe_instance *inst;
1960 ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset);
1964 /* If only rp->kp.addr is specified, check reregistering kprobes */
1965 if (rp->kp.addr && check_kprobe_rereg(&rp->kp))
1968 if (kretprobe_blacklist_size) {
1969 addr = kprobe_addr(&rp->kp);
1971 return PTR_ERR(addr);
1973 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1974 if (kretprobe_blacklist[i].addr == addr)
1979 rp->kp.pre_handler = pre_handler_kretprobe;
1980 rp->kp.post_handler = NULL;
1981 rp->kp.fault_handler = NULL;
1983 /* Pre-allocate memory for max kretprobe instances */
1984 if (rp->maxactive <= 0) {
1985 #ifdef CONFIG_PREEMPT
1986 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1988 rp->maxactive = num_possible_cpus();
1991 raw_spin_lock_init(&rp->lock);
1992 INIT_HLIST_HEAD(&rp->free_instances);
1993 for (i = 0; i < rp->maxactive; i++) {
1994 inst = kmalloc(sizeof(struct kretprobe_instance) +
1995 rp->data_size, GFP_KERNEL);
2000 INIT_HLIST_NODE(&inst->hlist);
2001 hlist_add_head(&inst->hlist, &rp->free_instances);
2005 /* Establish function entry probe point */
2006 ret = register_kprobe(&rp->kp);
2011 EXPORT_SYMBOL_GPL(register_kretprobe);
2013 int register_kretprobes(struct kretprobe **rps, int num)
2019 for (i = 0; i < num; i++) {
2020 ret = register_kretprobe(rps[i]);
2023 unregister_kretprobes(rps, i);
2029 EXPORT_SYMBOL_GPL(register_kretprobes);
2031 void unregister_kretprobe(struct kretprobe *rp)
2033 unregister_kretprobes(&rp, 1);
2035 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2037 void unregister_kretprobes(struct kretprobe **rps, int num)
2043 mutex_lock(&kprobe_mutex);
2044 for (i = 0; i < num; i++)
2045 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
2046 rps[i]->kp.addr = NULL;
2047 mutex_unlock(&kprobe_mutex);
2049 synchronize_sched();
2050 for (i = 0; i < num; i++) {
2051 if (rps[i]->kp.addr) {
2052 __unregister_kprobe_bottom(&rps[i]->kp);
2053 cleanup_rp_inst(rps[i]);
2057 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2059 #else /* CONFIG_KRETPROBES */
2060 int register_kretprobe(struct kretprobe *rp)
2064 EXPORT_SYMBOL_GPL(register_kretprobe);
2066 int register_kretprobes(struct kretprobe **rps, int num)
2070 EXPORT_SYMBOL_GPL(register_kretprobes);
2072 void unregister_kretprobe(struct kretprobe *rp)
2075 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2077 void unregister_kretprobes(struct kretprobe **rps, int num)
2080 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2082 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2086 NOKPROBE_SYMBOL(pre_handler_kretprobe);
2088 #endif /* CONFIG_KRETPROBES */
2090 /* Set the kprobe gone and remove its instruction buffer. */
2091 static void kill_kprobe(struct kprobe *p)
2095 if (WARN_ON_ONCE(kprobe_gone(p)))
2098 p->flags |= KPROBE_FLAG_GONE;
2099 if (kprobe_aggrprobe(p)) {
2101 * If this is an aggr_kprobe, we have to list all the
2102 * chained probes and mark them GONE.
2104 list_for_each_entry_rcu(kp, &p->list, list)
2105 kp->flags |= KPROBE_FLAG_GONE;
2106 p->post_handler = NULL;
2107 kill_optimized_kprobe(p);
2110 * Here, we can remove insn_slot safely, because no thread calls
2111 * the original probed function (which will be freed soon) any more.
2113 arch_remove_kprobe(p);
2116 * The module is going away. We should disarm the kprobe which
2117 * is using ftrace, because ftrace framework is still available at
2118 * MODULE_STATE_GOING notification.
2120 if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
2121 disarm_kprobe_ftrace(p);
2124 /* Disable one kprobe */
2125 int disable_kprobe(struct kprobe *kp)
2130 mutex_lock(&kprobe_mutex);
2132 /* Disable this kprobe */
2133 p = __disable_kprobe(kp);
2137 mutex_unlock(&kprobe_mutex);
2140 EXPORT_SYMBOL_GPL(disable_kprobe);
2142 /* Enable one kprobe */
2143 int enable_kprobe(struct kprobe *kp)
2148 mutex_lock(&kprobe_mutex);
2150 /* Check whether specified probe is valid. */
2151 p = __get_valid_kprobe(kp);
2152 if (unlikely(p == NULL)) {
2157 if (kprobe_gone(kp)) {
2158 /* This kprobe has gone, we couldn't enable it. */
2164 kp->flags &= ~KPROBE_FLAG_DISABLED;
2166 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2167 p->flags &= ~KPROBE_FLAG_DISABLED;
2168 ret = arm_kprobe(p);
2170 p->flags |= KPROBE_FLAG_DISABLED;
2173 mutex_unlock(&kprobe_mutex);
2176 EXPORT_SYMBOL_GPL(enable_kprobe);
2178 /* Caller must NOT call this in usual path. This is only for critical case */
2179 void dump_kprobe(struct kprobe *kp)
2181 pr_err("Dumping kprobe:\n");
2182 pr_err("Name: %s\nOffset: %x\nAddress: %pS\n",
2183 kp->symbol_name, kp->offset, kp->addr);
2185 NOKPROBE_SYMBOL(dump_kprobe);
2187 int kprobe_add_ksym_blacklist(unsigned long entry)
2189 struct kprobe_blacklist_entry *ent;
2190 unsigned long offset = 0, size = 0;
2192 if (!kernel_text_address(entry) ||
2193 !kallsyms_lookup_size_offset(entry, &size, &offset))
2196 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
2199 ent->start_addr = entry;
2200 ent->end_addr = entry + size;
2201 INIT_LIST_HEAD(&ent->list);
2202 list_add_tail(&ent->list, &kprobe_blacklist);
2207 /* Add all symbols in given area into kprobe blacklist */
2208 int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
2210 unsigned long entry;
2213 for (entry = start; entry < end; entry += ret) {
2214 ret = kprobe_add_ksym_blacklist(entry);
2217 if (ret == 0) /* In case of alias symbol */
2223 int __init __weak arch_populate_kprobe_blacklist(void)
2229 * Lookup and populate the kprobe_blacklist.
2231 * Unlike the kretprobe blacklist, we'll need to determine
2232 * the range of addresses that belong to the said functions,
2233 * since a kprobe need not necessarily be at the beginning
2236 static int __init populate_kprobe_blacklist(unsigned long *start,
2239 unsigned long entry;
2240 unsigned long *iter;
2243 for (iter = start; iter < end; iter++) {
2244 entry = arch_deref_entry_point((void *)*iter);
2245 ret = kprobe_add_ksym_blacklist(entry);
2252 /* Symbols in __kprobes_text are blacklisted */
2253 ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
2254 (unsigned long)__kprobes_text_end);
2256 return ret ? : arch_populate_kprobe_blacklist();
2259 /* Module notifier call back, checking kprobes on the module */
2260 static int kprobes_module_callback(struct notifier_block *nb,
2261 unsigned long val, void *data)
2263 struct module *mod = data;
2264 struct hlist_head *head;
2267 int checkcore = (val == MODULE_STATE_GOING);
2269 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
2273 * When MODULE_STATE_GOING was notified, both of module .text and
2274 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2275 * notified, only .init.text section would be freed. We need to
2276 * disable kprobes which have been inserted in the sections.
2278 mutex_lock(&kprobe_mutex);
2279 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2280 head = &kprobe_table[i];
2281 hlist_for_each_entry_rcu(p, head, hlist) {
2285 if (within_module_init((unsigned long)p->addr, mod) ||
2287 within_module_core((unsigned long)p->addr, mod))) {
2289 * The vaddr this probe is installed will soon
2290 * be vfreed buy not synced to disk. Hence,
2291 * disarming the breakpoint isn't needed.
2293 * Note, this will also move any optimized probes
2294 * that are pending to be removed from their
2295 * corresponding lists to the freeing_list and
2296 * will not be touched by the delayed
2297 * kprobe_optimizer work handler.
2303 mutex_unlock(&kprobe_mutex);
2307 static struct notifier_block kprobe_module_nb = {
2308 .notifier_call = kprobes_module_callback,
2312 /* Markers of _kprobe_blacklist section */
2313 extern unsigned long __start_kprobe_blacklist[];
2314 extern unsigned long __stop_kprobe_blacklist[];
2316 static int __init init_kprobes(void)
2320 /* FIXME allocate the probe table, currently defined statically */
2321 /* initialize all list heads */
2322 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2323 INIT_HLIST_HEAD(&kprobe_table[i]);
2324 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
2325 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
2328 err = populate_kprobe_blacklist(__start_kprobe_blacklist,
2329 __stop_kprobe_blacklist);
2331 pr_err("kprobes: failed to populate blacklist: %d\n", err);
2332 pr_err("Please take care of using kprobes.\n");
2335 if (kretprobe_blacklist_size) {
2336 /* lookup the function address from its name */
2337 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2338 kretprobe_blacklist[i].addr =
2339 kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
2340 if (!kretprobe_blacklist[i].addr)
2341 printk("kretprobe: lookup failed: %s\n",
2342 kretprobe_blacklist[i].name);
2346 #if defined(CONFIG_OPTPROBES)
2347 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2348 /* Init kprobe_optinsn_slots */
2349 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2351 /* By default, kprobes can be optimized */
2352 kprobes_allow_optimization = true;
2355 /* By default, kprobes are armed */
2356 kprobes_all_disarmed = false;
2358 err = arch_init_kprobes();
2360 err = register_die_notifier(&kprobe_exceptions_nb);
2362 err = register_module_notifier(&kprobe_module_nb);
2364 kprobes_initialized = (err == 0);
2371 #ifdef CONFIG_DEBUG_FS
2372 static void report_probe(struct seq_file *pi, struct kprobe *p,
2373 const char *sym, int offset, char *modname, struct kprobe *pp)
2376 void *addr = p->addr;
2378 if (p->pre_handler == pre_handler_kretprobe)
2383 if (!kallsyms_show_value(pi->file->f_cred))
2387 seq_printf(pi, "%px %s %s+0x%x %s ",
2388 addr, kprobe_type, sym, offset,
2389 (modname ? modname : " "));
2390 else /* try to use %pS */
2391 seq_printf(pi, "%px %s %pS ",
2392 addr, kprobe_type, p->addr);
2396 seq_printf(pi, "%s%s%s%s\n",
2397 (kprobe_gone(p) ? "[GONE]" : ""),
2398 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
2399 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
2400 (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
2403 static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2405 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2408 static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2411 if (*pos >= KPROBE_TABLE_SIZE)
2416 static void kprobe_seq_stop(struct seq_file *f, void *v)
2421 static int show_kprobe_addr(struct seq_file *pi, void *v)
2423 struct hlist_head *head;
2424 struct kprobe *p, *kp;
2425 const char *sym = NULL;
2426 unsigned int i = *(loff_t *) v;
2427 unsigned long offset = 0;
2428 char *modname, namebuf[KSYM_NAME_LEN];
2430 head = &kprobe_table[i];
2432 hlist_for_each_entry_rcu(p, head, hlist) {
2433 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2434 &offset, &modname, namebuf);
2435 if (kprobe_aggrprobe(p)) {
2436 list_for_each_entry_rcu(kp, &p->list, list)
2437 report_probe(pi, kp, sym, offset, modname, p);
2439 report_probe(pi, p, sym, offset, modname, NULL);
2445 static const struct seq_operations kprobes_seq_ops = {
2446 .start = kprobe_seq_start,
2447 .next = kprobe_seq_next,
2448 .stop = kprobe_seq_stop,
2449 .show = show_kprobe_addr
2452 static int kprobes_open(struct inode *inode, struct file *filp)
2454 return seq_open(filp, &kprobes_seq_ops);
2457 static const struct file_operations debugfs_kprobes_operations = {
2458 .open = kprobes_open,
2460 .llseek = seq_lseek,
2461 .release = seq_release,
2464 /* kprobes/blacklist -- shows which functions can not be probed */
2465 static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
2467 return seq_list_start(&kprobe_blacklist, *pos);
2470 static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
2472 return seq_list_next(v, &kprobe_blacklist, pos);
2475 static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
2477 struct kprobe_blacklist_entry *ent =
2478 list_entry(v, struct kprobe_blacklist_entry, list);
2481 * If /proc/kallsyms is not showing kernel address, we won't
2482 * show them here either.
2484 if (!kallsyms_show_value(m->file->f_cred))
2485 seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
2486 (void *)ent->start_addr);
2488 seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
2489 (void *)ent->end_addr, (void *)ent->start_addr);
2493 static const struct seq_operations kprobe_blacklist_seq_ops = {
2494 .start = kprobe_blacklist_seq_start,
2495 .next = kprobe_blacklist_seq_next,
2496 .stop = kprobe_seq_stop, /* Reuse void function */
2497 .show = kprobe_blacklist_seq_show,
2500 static int kprobe_blacklist_open(struct inode *inode, struct file *filp)
2502 return seq_open(filp, &kprobe_blacklist_seq_ops);
2505 static const struct file_operations debugfs_kprobe_blacklist_ops = {
2506 .open = kprobe_blacklist_open,
2508 .llseek = seq_lseek,
2509 .release = seq_release,
2512 static int arm_all_kprobes(void)
2514 struct hlist_head *head;
2516 unsigned int i, total = 0, errors = 0;
2519 mutex_lock(&kprobe_mutex);
2521 /* If kprobes are armed, just return */
2522 if (!kprobes_all_disarmed)
2523 goto already_enabled;
2526 * optimize_kprobe() called by arm_kprobe() checks
2527 * kprobes_all_disarmed, so set kprobes_all_disarmed before
2530 kprobes_all_disarmed = false;
2531 /* Arming kprobes doesn't optimize kprobe itself */
2532 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2533 head = &kprobe_table[i];
2534 /* Arm all kprobes on a best-effort basis */
2535 hlist_for_each_entry_rcu(p, head, hlist) {
2536 if (!kprobe_disabled(p)) {
2537 err = arm_kprobe(p);
2548 pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n",
2551 pr_info("Kprobes globally enabled\n");
2554 mutex_unlock(&kprobe_mutex);
2558 static int disarm_all_kprobes(void)
2560 struct hlist_head *head;
2562 unsigned int i, total = 0, errors = 0;
2565 mutex_lock(&kprobe_mutex);
2567 /* If kprobes are already disarmed, just return */
2568 if (kprobes_all_disarmed) {
2569 mutex_unlock(&kprobe_mutex);
2573 kprobes_all_disarmed = true;
2575 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2576 head = &kprobe_table[i];
2577 /* Disarm all kprobes on a best-effort basis */
2578 hlist_for_each_entry_rcu(p, head, hlist) {
2579 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
2580 err = disarm_kprobe(p, false);
2591 pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n",
2594 pr_info("Kprobes globally disabled\n");
2596 mutex_unlock(&kprobe_mutex);
2598 /* Wait for disarming all kprobes by optimizer */
2599 wait_for_kprobe_optimizer();
2605 * XXX: The debugfs bool file interface doesn't allow for callbacks
2606 * when the bool state is switched. We can reuse that facility when
2609 static ssize_t read_enabled_file_bool(struct file *file,
2610 char __user *user_buf, size_t count, loff_t *ppos)
2614 if (!kprobes_all_disarmed)
2620 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2623 static ssize_t write_enabled_file_bool(struct file *file,
2624 const char __user *user_buf, size_t count, loff_t *ppos)
2630 buf_size = min(count, (sizeof(buf)-1));
2631 if (copy_from_user(buf, user_buf, buf_size))
2634 buf[buf_size] = '\0';
2639 ret = arm_all_kprobes();
2644 ret = disarm_all_kprobes();
2656 static const struct file_operations fops_kp = {
2657 .read = read_enabled_file_bool,
2658 .write = write_enabled_file_bool,
2659 .llseek = default_llseek,
2662 static int __init debugfs_kprobe_init(void)
2664 struct dentry *dir, *file;
2665 unsigned int value = 1;
2667 dir = debugfs_create_dir("kprobes", NULL);
2671 file = debugfs_create_file("list", 0400, dir, NULL,
2672 &debugfs_kprobes_operations);
2676 file = debugfs_create_file("enabled", 0600, dir,
2681 file = debugfs_create_file("blacklist", 0400, dir, NULL,
2682 &debugfs_kprobe_blacklist_ops);
2689 debugfs_remove(dir);
2693 late_initcall(debugfs_kprobe_init);
2694 #endif /* CONFIG_DEBUG_FS */
2696 module_init(init_kprobes);