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/module.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/kdebug.h>
46 #include <linux/memory.h>
47 #include <linux/ftrace.h>
48 #include <linux/cpu.h>
50 #include <asm-generic/sections.h>
51 #include <asm/cacheflush.h>
52 #include <asm/errno.h>
53 #include <asm/uaccess.h>
55 #define KPROBE_HASH_BITS 6
56 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
60 * Some oddball architectures like 64bit powerpc have function descriptors
61 * so this must be overridable.
63 #ifndef kprobe_lookup_name
64 #define kprobe_lookup_name(name, addr) \
65 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
68 static int kprobes_initialized;
69 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
70 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
72 /* NOTE: change this value only with kprobe_mutex held */
73 static bool kprobes_all_disarmed;
75 static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
76 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
78 spinlock_t lock ____cacheline_aligned_in_smp;
79 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
81 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
83 return &(kretprobe_table_locks[hash].lock);
87 * Normally, functions that we'd want to prohibit kprobes in, are marked
88 * __kprobes. But, there are cases where such functions already belong to
89 * a different section (__sched for preempt_schedule)
91 * For such cases, we now have a blacklist
93 static struct kprobe_blackpoint kprobe_blacklist[] = {
94 {"preempt_schedule",},
95 {"native_get_debugreg",},
96 {"irq_entries_start",},
97 {"common_interrupt",},
98 {"mcount",}, /* mcount can be called from everywhere */
99 {NULL} /* Terminator */
102 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
104 * kprobe->ainsn.insn points to the copy of the instruction to be
105 * single-stepped. x86_64, POWER4 and above have no-exec support and
106 * stepping on the instruction on a vmalloced/kmalloced/data page
107 * is a recipe for disaster
109 struct kprobe_insn_page {
110 struct list_head list;
111 kprobe_opcode_t *insns; /* Page of instruction slots */
117 #define KPROBE_INSN_PAGE_SIZE(slots) \
118 (offsetof(struct kprobe_insn_page, slot_used) + \
119 (sizeof(char) * (slots)))
121 struct kprobe_insn_cache {
122 struct list_head pages; /* list of kprobe_insn_page */
123 size_t insn_size; /* size of instruction slot */
127 static int slots_per_page(struct kprobe_insn_cache *c)
129 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
132 enum kprobe_slot_state {
138 static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
139 static struct kprobe_insn_cache kprobe_insn_slots = {
140 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
141 .insn_size = MAX_INSN_SIZE,
144 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
147 * __get_insn_slot() - Find a slot on an executable page for an instruction.
148 * We allocate an executable page if there's no room on existing ones.
150 static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
152 struct kprobe_insn_page *kip;
155 list_for_each_entry(kip, &c->pages, list) {
156 if (kip->nused < slots_per_page(c)) {
158 for (i = 0; i < slots_per_page(c); i++) {
159 if (kip->slot_used[i] == SLOT_CLEAN) {
160 kip->slot_used[i] = SLOT_USED;
162 return kip->insns + (i * c->insn_size);
165 /* kip->nused is broken. Fix it. */
166 kip->nused = slots_per_page(c);
171 /* If there are any garbage slots, collect it and try again. */
172 if (c->nr_garbage && collect_garbage_slots(c) == 0)
175 /* All out of space. Need to allocate a new page. */
176 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
181 * Use module_alloc so this page is within +/- 2GB of where the
182 * kernel image and loaded module images reside. This is required
183 * so x86_64 can correctly handle the %rip-relative fixups.
185 kip->insns = module_alloc(PAGE_SIZE);
190 INIT_LIST_HEAD(&kip->list);
191 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
192 kip->slot_used[0] = SLOT_USED;
195 list_add(&kip->list, &c->pages);
200 kprobe_opcode_t __kprobes *get_insn_slot(void)
202 kprobe_opcode_t *ret = NULL;
204 mutex_lock(&kprobe_insn_mutex);
205 ret = __get_insn_slot(&kprobe_insn_slots);
206 mutex_unlock(&kprobe_insn_mutex);
211 /* Return 1 if all garbages are collected, otherwise 0. */
212 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
214 kip->slot_used[idx] = SLOT_CLEAN;
216 if (kip->nused == 0) {
218 * Page is no longer in use. Free it unless
219 * it's the last one. We keep the last one
220 * so as not to have to set it up again the
221 * next time somebody inserts a probe.
223 if (!list_is_singular(&kip->list)) {
224 list_del(&kip->list);
225 module_free(NULL, kip->insns);
233 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
235 struct kprobe_insn_page *kip, *next;
237 /* Ensure no-one is interrupted on the garbages */
240 list_for_each_entry_safe(kip, next, &c->pages, list) {
242 if (kip->ngarbage == 0)
244 kip->ngarbage = 0; /* we will collect all garbages */
245 for (i = 0; i < slots_per_page(c); i++) {
246 if (kip->slot_used[i] == SLOT_DIRTY &&
247 collect_one_slot(kip, i))
255 static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
256 kprobe_opcode_t *slot, int dirty)
258 struct kprobe_insn_page *kip;
260 list_for_each_entry(kip, &c->pages, list) {
261 long idx = ((long)slot - (long)kip->insns) / c->insn_size;
262 if (idx >= 0 && idx < slots_per_page(c)) {
263 WARN_ON(kip->slot_used[idx] != SLOT_USED);
265 kip->slot_used[idx] = SLOT_DIRTY;
267 if (++c->nr_garbage > slots_per_page(c))
268 collect_garbage_slots(c);
270 collect_one_slot(kip, idx);
274 /* Could not free this slot. */
278 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
280 mutex_lock(&kprobe_insn_mutex);
281 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
282 mutex_unlock(&kprobe_insn_mutex);
284 #ifdef CONFIG_OPTPROBES
285 /* For optimized_kprobe buffer */
286 static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
287 static struct kprobe_insn_cache kprobe_optinsn_slots = {
288 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
289 /* .insn_size is initialized later */
292 /* Get a slot for optimized_kprobe buffer */
293 kprobe_opcode_t __kprobes *get_optinsn_slot(void)
295 kprobe_opcode_t *ret = NULL;
297 mutex_lock(&kprobe_optinsn_mutex);
298 ret = __get_insn_slot(&kprobe_optinsn_slots);
299 mutex_unlock(&kprobe_optinsn_mutex);
304 void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
306 mutex_lock(&kprobe_optinsn_mutex);
307 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
308 mutex_unlock(&kprobe_optinsn_mutex);
313 /* We have preemption disabled.. so it is safe to use __ versions */
314 static inline void set_kprobe_instance(struct kprobe *kp)
316 __get_cpu_var(kprobe_instance) = kp;
319 static inline void reset_kprobe_instance(void)
321 __get_cpu_var(kprobe_instance) = NULL;
325 * This routine is called either:
326 * - under the kprobe_mutex - during kprobe_[un]register()
328 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
330 struct kprobe __kprobes *get_kprobe(void *addr)
332 struct hlist_head *head;
333 struct hlist_node *node;
336 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
337 hlist_for_each_entry_rcu(p, node, head, hlist) {
345 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
347 /* Return true if the kprobe is an aggregator */
348 static inline int kprobe_aggrprobe(struct kprobe *p)
350 return p->pre_handler == aggr_pre_handler;
354 * Keep all fields in the kprobe consistent
356 static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
358 memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
359 memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
362 #ifdef CONFIG_OPTPROBES
364 * Call all pre_handler on the list, but ignores its return value.
365 * This must be called from arch-dep optimized caller.
367 void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
371 list_for_each_entry_rcu(kp, &p->list, list) {
372 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
373 set_kprobe_instance(kp);
374 kp->pre_handler(kp, regs);
376 reset_kprobe_instance();
380 /* Return true(!0) if the kprobe is ready for optimization. */
381 static inline int kprobe_optready(struct kprobe *p)
383 struct optimized_kprobe *op;
385 if (kprobe_aggrprobe(p)) {
386 op = container_of(p, struct optimized_kprobe, kp);
387 return arch_prepared_optinsn(&op->optinsn);
394 * Return an optimized kprobe whose optimizing code replaces
395 * instructions including addr (exclude breakpoint).
397 struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
400 struct kprobe *p = NULL;
401 struct optimized_kprobe *op;
403 /* Don't check i == 0, since that is a breakpoint case. */
404 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
405 p = get_kprobe((void *)(addr - i));
407 if (p && kprobe_optready(p)) {
408 op = container_of(p, struct optimized_kprobe, kp);
409 if (arch_within_optimized_kprobe(op, addr))
416 /* Optimization staging list, protected by kprobe_mutex */
417 static LIST_HEAD(optimizing_list);
419 static void kprobe_optimizer(struct work_struct *work);
420 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
421 #define OPTIMIZE_DELAY 5
423 /* Kprobe jump optimizer */
424 static __kprobes void kprobe_optimizer(struct work_struct *work)
426 struct optimized_kprobe *op, *tmp;
428 /* Lock modules while optimizing kprobes */
429 mutex_lock(&module_mutex);
430 mutex_lock(&kprobe_mutex);
431 if (kprobes_all_disarmed)
435 * Wait for quiesence period to ensure all running interrupts
436 * are done. Because optprobe may modify multiple instructions
437 * there is a chance that Nth instruction is interrupted. In that
438 * case, running interrupt can return to 2nd-Nth byte of jump
439 * instruction. This wait is for avoiding it.
444 * The optimization/unoptimization refers online_cpus via
445 * stop_machine() and cpu-hotplug modifies online_cpus.
446 * And same time, text_mutex will be held in cpu-hotplug and here.
447 * This combination can cause a deadlock (cpu-hotplug try to lock
448 * text_mutex but stop_machine can not be done because online_cpus
450 * To avoid this deadlock, we need to call get_online_cpus()
451 * for preventing cpu-hotplug outside of text_mutex locking.
454 mutex_lock(&text_mutex);
455 list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
456 WARN_ON(kprobe_disabled(&op->kp));
457 if (arch_optimize_kprobe(op) < 0)
458 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
459 list_del_init(&op->list);
461 mutex_unlock(&text_mutex);
464 mutex_unlock(&kprobe_mutex);
465 mutex_unlock(&module_mutex);
468 /* Optimize kprobe if p is ready to be optimized */
469 static __kprobes void optimize_kprobe(struct kprobe *p)
471 struct optimized_kprobe *op;
473 /* Check if the kprobe is disabled or not ready for optimization. */
474 if (!kprobe_optready(p) ||
475 (kprobe_disabled(p) || kprobes_all_disarmed))
478 /* Both of break_handler and post_handler are not supported. */
479 if (p->break_handler || p->post_handler)
482 op = container_of(p, struct optimized_kprobe, kp);
484 /* Check there is no other kprobes at the optimized instructions */
485 if (arch_check_optimized_kprobe(op) < 0)
488 /* Check if it is already optimized. */
489 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
492 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
493 list_add(&op->list, &optimizing_list);
494 if (!delayed_work_pending(&optimizing_work))
495 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
498 /* Unoptimize a kprobe if p is optimized */
499 static __kprobes void unoptimize_kprobe(struct kprobe *p)
501 struct optimized_kprobe *op;
503 if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
504 op = container_of(p, struct optimized_kprobe, kp);
505 if (!list_empty(&op->list))
506 /* Dequeue from the optimization queue */
507 list_del_init(&op->list);
509 /* Replace jump with break */
510 arch_unoptimize_kprobe(op);
511 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
515 /* Remove optimized instructions */
516 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
518 struct optimized_kprobe *op;
520 op = container_of(p, struct optimized_kprobe, kp);
521 if (!list_empty(&op->list)) {
522 /* Dequeue from the optimization queue */
523 list_del_init(&op->list);
524 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
526 /* Don't unoptimize, because the target code will be freed. */
527 arch_remove_optimized_kprobe(op);
530 /* Try to prepare optimized instructions */
531 static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
533 struct optimized_kprobe *op;
535 op = container_of(p, struct optimized_kprobe, kp);
536 arch_prepare_optimized_kprobe(op);
539 /* Free optimized instructions and optimized_kprobe */
540 static __kprobes void free_aggr_kprobe(struct kprobe *p)
542 struct optimized_kprobe *op;
544 op = container_of(p, struct optimized_kprobe, kp);
545 arch_remove_optimized_kprobe(op);
549 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
550 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
552 struct optimized_kprobe *op;
554 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
558 INIT_LIST_HEAD(&op->list);
559 op->kp.addr = p->addr;
560 arch_prepare_optimized_kprobe(op);
565 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
568 * Prepare an optimized_kprobe and optimize it
569 * NOTE: p must be a normal registered kprobe
571 static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
574 struct optimized_kprobe *op;
576 ap = alloc_aggr_kprobe(p);
580 op = container_of(ap, struct optimized_kprobe, kp);
581 if (!arch_prepared_optinsn(&op->optinsn)) {
582 /* If failed to setup optimizing, fallback to kprobe */
583 free_aggr_kprobe(ap);
587 init_aggr_kprobe(ap, p);
591 static void __kprobes __arm_kprobe(struct kprobe *p)
593 struct kprobe *old_p;
595 /* Check collision with other optimized kprobes */
596 old_p = get_optimized_kprobe((unsigned long)p->addr);
598 unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
601 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
604 static void __kprobes __disarm_kprobe(struct kprobe *p)
606 struct kprobe *old_p;
608 unoptimize_kprobe(p); /* Try to unoptimize */
609 arch_disarm_kprobe(p);
611 /* If another kprobe was blocked, optimize it. */
612 old_p = get_optimized_kprobe((unsigned long)p->addr);
614 optimize_kprobe(old_p);
617 #else /* !CONFIG_OPTPROBES */
619 #define optimize_kprobe(p) do {} while (0)
620 #define unoptimize_kprobe(p) do {} while (0)
621 #define kill_optimized_kprobe(p) do {} while (0)
622 #define prepare_optimized_kprobe(p) do {} while (0)
623 #define try_to_optimize_kprobe(p) do {} while (0)
624 #define __arm_kprobe(p) arch_arm_kprobe(p)
625 #define __disarm_kprobe(p) arch_disarm_kprobe(p)
627 static __kprobes void free_aggr_kprobe(struct kprobe *p)
632 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
634 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
636 #endif /* CONFIG_OPTPROBES */
638 /* Arm a kprobe with text_mutex */
639 static void __kprobes arm_kprobe(struct kprobe *kp)
642 * Here, since __arm_kprobe() doesn't use stop_machine(),
643 * this doesn't cause deadlock on text_mutex. So, we don't
644 * need get_online_cpus().
646 mutex_lock(&text_mutex);
648 mutex_unlock(&text_mutex);
651 /* Disarm a kprobe with text_mutex */
652 static void __kprobes disarm_kprobe(struct kprobe *kp)
654 get_online_cpus(); /* For avoiding text_mutex deadlock */
655 mutex_lock(&text_mutex);
657 mutex_unlock(&text_mutex);
662 * Aggregate handlers for multiple kprobes support - these handlers
663 * take care of invoking the individual kprobe handlers on p->list
665 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
669 list_for_each_entry_rcu(kp, &p->list, list) {
670 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
671 set_kprobe_instance(kp);
672 if (kp->pre_handler(kp, regs))
675 reset_kprobe_instance();
680 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
685 list_for_each_entry_rcu(kp, &p->list, list) {
686 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
687 set_kprobe_instance(kp);
688 kp->post_handler(kp, regs, flags);
689 reset_kprobe_instance();
694 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
697 struct kprobe *cur = __get_cpu_var(kprobe_instance);
700 * if we faulted "during" the execution of a user specified
701 * probe handler, invoke just that probe's fault handler
703 if (cur && cur->fault_handler) {
704 if (cur->fault_handler(cur, regs, trapnr))
710 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
712 struct kprobe *cur = __get_cpu_var(kprobe_instance);
715 if (cur && cur->break_handler) {
716 if (cur->break_handler(cur, regs))
719 reset_kprobe_instance();
723 /* Walks the list and increments nmissed count for multiprobe case */
724 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
727 if (!kprobe_aggrprobe(p)) {
730 list_for_each_entry_rcu(kp, &p->list, list)
736 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
737 struct hlist_head *head)
739 struct kretprobe *rp = ri->rp;
741 /* remove rp inst off the rprobe_inst_table */
742 hlist_del(&ri->hlist);
743 INIT_HLIST_NODE(&ri->hlist);
745 spin_lock(&rp->lock);
746 hlist_add_head(&ri->hlist, &rp->free_instances);
747 spin_unlock(&rp->lock);
750 hlist_add_head(&ri->hlist, head);
753 void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
754 struct hlist_head **head, unsigned long *flags)
756 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
757 spinlock_t *hlist_lock;
759 *head = &kretprobe_inst_table[hash];
760 hlist_lock = kretprobe_table_lock_ptr(hash);
761 spin_lock_irqsave(hlist_lock, *flags);
764 static void __kprobes kretprobe_table_lock(unsigned long hash,
765 unsigned long *flags)
767 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
768 spin_lock_irqsave(hlist_lock, *flags);
771 void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
772 unsigned long *flags)
774 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
775 spinlock_t *hlist_lock;
777 hlist_lock = kretprobe_table_lock_ptr(hash);
778 spin_unlock_irqrestore(hlist_lock, *flags);
781 void __kprobes kretprobe_table_unlock(unsigned long hash, unsigned long *flags)
783 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
784 spin_unlock_irqrestore(hlist_lock, *flags);
788 * This function is called from finish_task_switch when task tk becomes dead,
789 * so that we can recycle any function-return probe instances associated
790 * with this task. These left over instances represent probed functions
791 * that have been called but will never return.
793 void __kprobes kprobe_flush_task(struct task_struct *tk)
795 struct kretprobe_instance *ri;
796 struct hlist_head *head, empty_rp;
797 struct hlist_node *node, *tmp;
798 unsigned long hash, flags = 0;
800 if (unlikely(!kprobes_initialized))
801 /* Early boot. kretprobe_table_locks not yet initialized. */
804 hash = hash_ptr(tk, KPROBE_HASH_BITS);
805 head = &kretprobe_inst_table[hash];
806 kretprobe_table_lock(hash, &flags);
807 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
809 recycle_rp_inst(ri, &empty_rp);
811 kretprobe_table_unlock(hash, &flags);
812 INIT_HLIST_HEAD(&empty_rp);
813 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
814 hlist_del(&ri->hlist);
819 static inline void free_rp_inst(struct kretprobe *rp)
821 struct kretprobe_instance *ri;
822 struct hlist_node *pos, *next;
824 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
825 hlist_del(&ri->hlist);
830 static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
832 unsigned long flags, hash;
833 struct kretprobe_instance *ri;
834 struct hlist_node *pos, *next;
835 struct hlist_head *head;
838 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
839 kretprobe_table_lock(hash, &flags);
840 head = &kretprobe_inst_table[hash];
841 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
845 kretprobe_table_unlock(hash, &flags);
851 * Add the new probe to ap->list. Fail if this is the
852 * second jprobe at the address - two jprobes can't coexist
854 static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
856 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
858 if (p->break_handler || p->post_handler)
859 unoptimize_kprobe(ap); /* Fall back to normal kprobe */
861 if (p->break_handler) {
862 if (ap->break_handler)
864 list_add_tail_rcu(&p->list, &ap->list);
865 ap->break_handler = aggr_break_handler;
867 list_add_rcu(&p->list, &ap->list);
868 if (p->post_handler && !ap->post_handler)
869 ap->post_handler = aggr_post_handler;
871 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
872 ap->flags &= ~KPROBE_FLAG_DISABLED;
873 if (!kprobes_all_disarmed)
874 /* Arm the breakpoint again. */
881 * Fill in the required fields of the "manager kprobe". Replace the
882 * earlier kprobe in the hlist with the manager kprobe
884 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
886 /* Copy p's insn slot to ap */
890 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
891 ap->pre_handler = aggr_pre_handler;
892 ap->fault_handler = aggr_fault_handler;
893 /* We don't care the kprobe which has gone. */
894 if (p->post_handler && !kprobe_gone(p))
895 ap->post_handler = aggr_post_handler;
896 if (p->break_handler && !kprobe_gone(p))
897 ap->break_handler = aggr_break_handler;
899 INIT_LIST_HEAD(&ap->list);
900 INIT_HLIST_NODE(&ap->hlist);
902 list_add_rcu(&p->list, &ap->list);
903 hlist_replace_rcu(&p->hlist, &ap->hlist);
907 * This is the second or subsequent kprobe at the address - handle
910 static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
914 struct kprobe *ap = old_p;
916 if (!kprobe_aggrprobe(old_p)) {
917 /* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
918 ap = alloc_aggr_kprobe(old_p);
921 init_aggr_kprobe(ap, old_p);
924 if (kprobe_gone(ap)) {
926 * Attempting to insert new probe at the same location that
927 * had a probe in the module vaddr area which already
928 * freed. So, the instruction slot has already been
929 * released. We need a new slot for the new probe.
931 ret = arch_prepare_kprobe(ap);
934 * Even if fail to allocate new slot, don't need to
935 * free aggr_probe. It will be used next time, or
936 * freed by unregister_kprobe.
940 /* Prepare optimized instructions if possible. */
941 prepare_optimized_kprobe(ap);
944 * Clear gone flag to prevent allocating new slot again, and
945 * set disabled flag because it is not armed yet.
947 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
948 | KPROBE_FLAG_DISABLED;
951 /* Copy ap's insn slot to p */
953 return add_new_kprobe(ap, p);
956 /* Try to disable aggr_kprobe, and return 1 if succeeded.*/
957 static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
961 list_for_each_entry_rcu(kp, &p->list, list) {
962 if (!kprobe_disabled(kp))
964 * There is an active probe on the list.
965 * We can't disable aggr_kprobe.
969 p->flags |= KPROBE_FLAG_DISABLED;
973 static int __kprobes in_kprobes_functions(unsigned long addr)
975 struct kprobe_blackpoint *kb;
977 if (addr >= (unsigned long)__kprobes_text_start &&
978 addr < (unsigned long)__kprobes_text_end)
981 * If there exists a kprobe_blacklist, verify and
982 * fail any probe registration in the prohibited area
984 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
985 if (kb->start_addr) {
986 if (addr >= kb->start_addr &&
987 addr < (kb->start_addr + kb->range))
995 * If we have a symbol_name argument, look it up and add the offset field
996 * to it. This way, we can specify a relative address to a symbol.
998 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
1000 kprobe_opcode_t *addr = p->addr;
1001 if (p->symbol_name) {
1004 kprobe_lookup_name(p->symbol_name, addr);
1009 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
1012 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1013 static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1015 struct kprobe *old_p, *list_p;
1017 old_p = get_kprobe(p->addr);
1018 if (unlikely(!old_p))
1022 list_for_each_entry_rcu(list_p, &old_p->list, list)
1024 /* kprobe p is a valid probe */
1032 /* Return error if the kprobe is being re-registered */
1033 static inline int check_kprobe_rereg(struct kprobe *p)
1036 struct kprobe *old_p;
1038 mutex_lock(&kprobe_mutex);
1039 old_p = __get_valid_kprobe(p);
1042 mutex_unlock(&kprobe_mutex);
1046 int __kprobes register_kprobe(struct kprobe *p)
1049 struct kprobe *old_p;
1050 struct module *probed_mod;
1051 kprobe_opcode_t *addr;
1053 addr = kprobe_addr(p);
1058 ret = check_kprobe_rereg(p);
1063 if (!kernel_text_address((unsigned long) p->addr) ||
1064 in_kprobes_functions((unsigned long) p->addr) ||
1065 ftrace_text_reserved(p->addr, p->addr)) {
1070 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1071 p->flags &= KPROBE_FLAG_DISABLED;
1074 * Check if are we probing a module.
1076 probed_mod = __module_text_address((unsigned long) p->addr);
1079 * We must hold a refcount of the probed module while updating
1080 * its code to prohibit unexpected unloading.
1082 if (unlikely(!try_module_get(probed_mod))) {
1087 * If the module freed .init.text, we couldn't insert
1090 if (within_module_init((unsigned long)p->addr, probed_mod) &&
1091 probed_mod->state != MODULE_STATE_COMING) {
1092 module_put(probed_mod);
1100 INIT_LIST_HEAD(&p->list);
1101 mutex_lock(&kprobe_mutex);
1103 get_online_cpus(); /* For avoiding text_mutex deadlock. */
1104 mutex_lock(&text_mutex);
1106 old_p = get_kprobe(p->addr);
1108 /* Since this may unoptimize old_p, locking text_mutex. */
1109 ret = register_aggr_kprobe(old_p, p);
1113 ret = arch_prepare_kprobe(p);
1117 INIT_HLIST_NODE(&p->hlist);
1118 hlist_add_head_rcu(&p->hlist,
1119 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1121 if (!kprobes_all_disarmed && !kprobe_disabled(p))
1124 /* Try to optimize kprobe */
1125 try_to_optimize_kprobe(p);
1128 mutex_unlock(&text_mutex);
1130 mutex_unlock(&kprobe_mutex);
1133 module_put(probed_mod);
1137 EXPORT_SYMBOL_GPL(register_kprobe);
1140 * Unregister a kprobe without a scheduler synchronization.
1142 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1144 struct kprobe *old_p, *list_p;
1146 old_p = __get_valid_kprobe(p);
1151 (kprobe_aggrprobe(old_p) &&
1152 list_is_singular(&old_p->list))) {
1154 * Only probe on the hash list. Disarm only if kprobes are
1155 * enabled and not gone - otherwise, the breakpoint would
1156 * already have been removed. We save on flushing icache.
1158 if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
1159 disarm_kprobe(old_p);
1160 hlist_del_rcu(&old_p->hlist);
1162 if (p->break_handler && !kprobe_gone(p))
1163 old_p->break_handler = NULL;
1164 if (p->post_handler && !kprobe_gone(p)) {
1165 list_for_each_entry_rcu(list_p, &old_p->list, list) {
1166 if ((list_p != p) && (list_p->post_handler))
1169 old_p->post_handler = NULL;
1172 list_del_rcu(&p->list);
1173 if (!kprobe_disabled(old_p)) {
1174 try_to_disable_aggr_kprobe(old_p);
1175 if (!kprobes_all_disarmed) {
1176 if (kprobe_disabled(old_p))
1177 disarm_kprobe(old_p);
1179 /* Try to optimize this probe again */
1180 optimize_kprobe(old_p);
1187 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1189 struct kprobe *old_p;
1191 if (list_empty(&p->list))
1192 arch_remove_kprobe(p);
1193 else if (list_is_singular(&p->list)) {
1194 /* "p" is the last child of an aggr_kprobe */
1195 old_p = list_entry(p->list.next, struct kprobe, list);
1197 arch_remove_kprobe(old_p);
1198 free_aggr_kprobe(old_p);
1202 int __kprobes register_kprobes(struct kprobe **kps, int num)
1208 for (i = 0; i < num; i++) {
1209 ret = register_kprobe(kps[i]);
1212 unregister_kprobes(kps, i);
1218 EXPORT_SYMBOL_GPL(register_kprobes);
1220 void __kprobes unregister_kprobe(struct kprobe *p)
1222 unregister_kprobes(&p, 1);
1224 EXPORT_SYMBOL_GPL(unregister_kprobe);
1226 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1232 mutex_lock(&kprobe_mutex);
1233 for (i = 0; i < num; i++)
1234 if (__unregister_kprobe_top(kps[i]) < 0)
1235 kps[i]->addr = NULL;
1236 mutex_unlock(&kprobe_mutex);
1238 synchronize_sched();
1239 for (i = 0; i < num; i++)
1241 __unregister_kprobe_bottom(kps[i]);
1243 EXPORT_SYMBOL_GPL(unregister_kprobes);
1245 static struct notifier_block kprobe_exceptions_nb = {
1246 .notifier_call = kprobe_exceptions_notify,
1247 .priority = 0x7fffffff /* we need to be notified first */
1250 unsigned long __weak arch_deref_entry_point(void *entry)
1252 return (unsigned long)entry;
1255 int __kprobes register_jprobes(struct jprobe **jps, int num)
1262 for (i = 0; i < num; i++) {
1265 addr = arch_deref_entry_point(jp->entry);
1267 if (!kernel_text_address(addr))
1270 /* Todo: Verify probepoint is a function entry point */
1271 jp->kp.pre_handler = setjmp_pre_handler;
1272 jp->kp.break_handler = longjmp_break_handler;
1273 ret = register_kprobe(&jp->kp);
1277 unregister_jprobes(jps, i);
1283 EXPORT_SYMBOL_GPL(register_jprobes);
1285 int __kprobes register_jprobe(struct jprobe *jp)
1287 return register_jprobes(&jp, 1);
1289 EXPORT_SYMBOL_GPL(register_jprobe);
1291 void __kprobes unregister_jprobe(struct jprobe *jp)
1293 unregister_jprobes(&jp, 1);
1295 EXPORT_SYMBOL_GPL(unregister_jprobe);
1297 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1303 mutex_lock(&kprobe_mutex);
1304 for (i = 0; i < num; i++)
1305 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1306 jps[i]->kp.addr = NULL;
1307 mutex_unlock(&kprobe_mutex);
1309 synchronize_sched();
1310 for (i = 0; i < num; i++) {
1311 if (jps[i]->kp.addr)
1312 __unregister_kprobe_bottom(&jps[i]->kp);
1315 EXPORT_SYMBOL_GPL(unregister_jprobes);
1317 #ifdef CONFIG_KRETPROBES
1319 * This kprobe pre_handler is registered with every kretprobe. When probe
1320 * hits it will set up the return probe.
1322 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1323 struct pt_regs *regs)
1325 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1326 unsigned long hash, flags = 0;
1327 struct kretprobe_instance *ri;
1329 /*TODO: consider to only swap the RA after the last pre_handler fired */
1330 hash = hash_ptr(current, KPROBE_HASH_BITS);
1331 spin_lock_irqsave(&rp->lock, flags);
1332 if (!hlist_empty(&rp->free_instances)) {
1333 ri = hlist_entry(rp->free_instances.first,
1334 struct kretprobe_instance, hlist);
1335 hlist_del(&ri->hlist);
1336 spin_unlock_irqrestore(&rp->lock, flags);
1341 if (rp->entry_handler && rp->entry_handler(ri, regs))
1344 arch_prepare_kretprobe(ri, regs);
1346 /* XXX(hch): why is there no hlist_move_head? */
1347 INIT_HLIST_NODE(&ri->hlist);
1348 kretprobe_table_lock(hash, &flags);
1349 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1350 kretprobe_table_unlock(hash, &flags);
1353 spin_unlock_irqrestore(&rp->lock, flags);
1358 int __kprobes register_kretprobe(struct kretprobe *rp)
1361 struct kretprobe_instance *inst;
1365 if (kretprobe_blacklist_size) {
1366 addr = kprobe_addr(&rp->kp);
1370 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1371 if (kretprobe_blacklist[i].addr == addr)
1376 rp->kp.pre_handler = pre_handler_kretprobe;
1377 rp->kp.post_handler = NULL;
1378 rp->kp.fault_handler = NULL;
1379 rp->kp.break_handler = NULL;
1381 /* Pre-allocate memory for max kretprobe instances */
1382 if (rp->maxactive <= 0) {
1383 #ifdef CONFIG_PREEMPT
1384 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1386 rp->maxactive = num_possible_cpus();
1389 spin_lock_init(&rp->lock);
1390 INIT_HLIST_HEAD(&rp->free_instances);
1391 for (i = 0; i < rp->maxactive; i++) {
1392 inst = kmalloc(sizeof(struct kretprobe_instance) +
1393 rp->data_size, GFP_KERNEL);
1398 INIT_HLIST_NODE(&inst->hlist);
1399 hlist_add_head(&inst->hlist, &rp->free_instances);
1403 /* Establish function entry probe point */
1404 ret = register_kprobe(&rp->kp);
1409 EXPORT_SYMBOL_GPL(register_kretprobe);
1411 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1417 for (i = 0; i < num; i++) {
1418 ret = register_kretprobe(rps[i]);
1421 unregister_kretprobes(rps, i);
1427 EXPORT_SYMBOL_GPL(register_kretprobes);
1429 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1431 unregister_kretprobes(&rp, 1);
1433 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1435 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1441 mutex_lock(&kprobe_mutex);
1442 for (i = 0; i < num; i++)
1443 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1444 rps[i]->kp.addr = NULL;
1445 mutex_unlock(&kprobe_mutex);
1447 synchronize_sched();
1448 for (i = 0; i < num; i++) {
1449 if (rps[i]->kp.addr) {
1450 __unregister_kprobe_bottom(&rps[i]->kp);
1451 cleanup_rp_inst(rps[i]);
1455 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1457 #else /* CONFIG_KRETPROBES */
1458 int __kprobes register_kretprobe(struct kretprobe *rp)
1462 EXPORT_SYMBOL_GPL(register_kretprobe);
1464 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1468 EXPORT_SYMBOL_GPL(register_kretprobes);
1470 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1473 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1475 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1478 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1480 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1481 struct pt_regs *regs)
1486 #endif /* CONFIG_KRETPROBES */
1488 /* Set the kprobe gone and remove its instruction buffer. */
1489 static void __kprobes kill_kprobe(struct kprobe *p)
1493 p->flags |= KPROBE_FLAG_GONE;
1494 if (kprobe_aggrprobe(p)) {
1496 * If this is an aggr_kprobe, we have to list all the
1497 * chained probes and mark them GONE.
1499 list_for_each_entry_rcu(kp, &p->list, list)
1500 kp->flags |= KPROBE_FLAG_GONE;
1501 p->post_handler = NULL;
1502 p->break_handler = NULL;
1503 kill_optimized_kprobe(p);
1506 * Here, we can remove insn_slot safely, because no thread calls
1507 * the original probed function (which will be freed soon) any more.
1509 arch_remove_kprobe(p);
1512 void __kprobes dump_kprobe(struct kprobe *kp)
1514 printk(KERN_WARNING "Dumping kprobe:\n");
1515 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1516 kp->symbol_name, kp->addr, kp->offset);
1519 /* Module notifier call back, checking kprobes on the module */
1520 static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1521 unsigned long val, void *data)
1523 struct module *mod = data;
1524 struct hlist_head *head;
1525 struct hlist_node *node;
1528 int checkcore = (val == MODULE_STATE_GOING);
1530 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1534 * When MODULE_STATE_GOING was notified, both of module .text and
1535 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1536 * notified, only .init.text section would be freed. We need to
1537 * disable kprobes which have been inserted in the sections.
1539 mutex_lock(&kprobe_mutex);
1540 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1541 head = &kprobe_table[i];
1542 hlist_for_each_entry_rcu(p, node, head, hlist)
1543 if (within_module_init((unsigned long)p->addr, mod) ||
1545 within_module_core((unsigned long)p->addr, mod))) {
1547 * The vaddr this probe is installed will soon
1548 * be vfreed buy not synced to disk. Hence,
1549 * disarming the breakpoint isn't needed.
1554 mutex_unlock(&kprobe_mutex);
1558 static struct notifier_block kprobe_module_nb = {
1559 .notifier_call = kprobes_module_callback,
1563 static int __init init_kprobes(void)
1566 unsigned long offset = 0, size = 0;
1567 char *modname, namebuf[128];
1568 const char *symbol_name;
1570 struct kprobe_blackpoint *kb;
1572 /* FIXME allocate the probe table, currently defined statically */
1573 /* initialize all list heads */
1574 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1575 INIT_HLIST_HEAD(&kprobe_table[i]);
1576 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1577 spin_lock_init(&(kretprobe_table_locks[i].lock));
1581 * Lookup and populate the kprobe_blacklist.
1583 * Unlike the kretprobe blacklist, we'll need to determine
1584 * the range of addresses that belong to the said functions,
1585 * since a kprobe need not necessarily be at the beginning
1588 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1589 kprobe_lookup_name(kb->name, addr);
1593 kb->start_addr = (unsigned long)addr;
1594 symbol_name = kallsyms_lookup(kb->start_addr,
1595 &size, &offset, &modname, namebuf);
1602 if (kretprobe_blacklist_size) {
1603 /* lookup the function address from its name */
1604 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1605 kprobe_lookup_name(kretprobe_blacklist[i].name,
1606 kretprobe_blacklist[i].addr);
1607 if (!kretprobe_blacklist[i].addr)
1608 printk("kretprobe: lookup failed: %s\n",
1609 kretprobe_blacklist[i].name);
1613 #if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
1614 /* Init kprobe_optinsn_slots */
1615 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
1618 /* By default, kprobes are armed */
1619 kprobes_all_disarmed = false;
1621 err = arch_init_kprobes();
1623 err = register_die_notifier(&kprobe_exceptions_nb);
1625 err = register_module_notifier(&kprobe_module_nb);
1627 kprobes_initialized = (err == 0);
1634 #ifdef CONFIG_DEBUG_FS
1635 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
1636 const char *sym, int offset, char *modname, struct kprobe *pp)
1640 if (p->pre_handler == pre_handler_kretprobe)
1642 else if (p->pre_handler == setjmp_pre_handler)
1648 seq_printf(pi, "%p %s %s+0x%x %s ",
1649 p->addr, kprobe_type, sym, offset,
1650 (modname ? modname : " "));
1652 seq_printf(pi, "%p %s %p ",
1653 p->addr, kprobe_type, p->addr);
1657 seq_printf(pi, "%s%s%s\n",
1658 (kprobe_gone(p) ? "[GONE]" : ""),
1659 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
1660 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
1663 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
1665 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
1668 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
1671 if (*pos >= KPROBE_TABLE_SIZE)
1676 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
1681 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
1683 struct hlist_head *head;
1684 struct hlist_node *node;
1685 struct kprobe *p, *kp;
1686 const char *sym = NULL;
1687 unsigned int i = *(loff_t *) v;
1688 unsigned long offset = 0;
1689 char *modname, namebuf[128];
1691 head = &kprobe_table[i];
1693 hlist_for_each_entry_rcu(p, node, head, hlist) {
1694 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
1695 &offset, &modname, namebuf);
1696 if (kprobe_aggrprobe(p)) {
1697 list_for_each_entry_rcu(kp, &p->list, list)
1698 report_probe(pi, kp, sym, offset, modname, p);
1700 report_probe(pi, p, sym, offset, modname, NULL);
1706 static const struct seq_operations kprobes_seq_ops = {
1707 .start = kprobe_seq_start,
1708 .next = kprobe_seq_next,
1709 .stop = kprobe_seq_stop,
1710 .show = show_kprobe_addr
1713 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
1715 return seq_open(filp, &kprobes_seq_ops);
1718 static const struct file_operations debugfs_kprobes_operations = {
1719 .open = kprobes_open,
1721 .llseek = seq_lseek,
1722 .release = seq_release,
1725 /* Disable one kprobe */
1726 int __kprobes disable_kprobe(struct kprobe *kp)
1731 mutex_lock(&kprobe_mutex);
1733 /* Check whether specified probe is valid. */
1734 p = __get_valid_kprobe(kp);
1735 if (unlikely(p == NULL)) {
1740 /* If the probe is already disabled (or gone), just return */
1741 if (kprobe_disabled(kp))
1744 kp->flags |= KPROBE_FLAG_DISABLED;
1746 /* When kp != p, p is always enabled. */
1747 try_to_disable_aggr_kprobe(p);
1749 if (!kprobes_all_disarmed && kprobe_disabled(p))
1752 mutex_unlock(&kprobe_mutex);
1755 EXPORT_SYMBOL_GPL(disable_kprobe);
1757 /* Enable one kprobe */
1758 int __kprobes enable_kprobe(struct kprobe *kp)
1763 mutex_lock(&kprobe_mutex);
1765 /* Check whether specified probe is valid. */
1766 p = __get_valid_kprobe(kp);
1767 if (unlikely(p == NULL)) {
1772 if (kprobe_gone(kp)) {
1773 /* This kprobe has gone, we couldn't enable it. */
1779 kp->flags &= ~KPROBE_FLAG_DISABLED;
1781 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1782 p->flags &= ~KPROBE_FLAG_DISABLED;
1786 mutex_unlock(&kprobe_mutex);
1789 EXPORT_SYMBOL_GPL(enable_kprobe);
1791 static void __kprobes arm_all_kprobes(void)
1793 struct hlist_head *head;
1794 struct hlist_node *node;
1798 mutex_lock(&kprobe_mutex);
1800 /* If kprobes are armed, just return */
1801 if (!kprobes_all_disarmed)
1802 goto already_enabled;
1804 /* Arming kprobes doesn't optimize kprobe itself */
1805 mutex_lock(&text_mutex);
1806 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1807 head = &kprobe_table[i];
1808 hlist_for_each_entry_rcu(p, node, head, hlist)
1809 if (!kprobe_disabled(p))
1812 mutex_unlock(&text_mutex);
1814 kprobes_all_disarmed = false;
1815 printk(KERN_INFO "Kprobes globally enabled\n");
1818 mutex_unlock(&kprobe_mutex);
1822 static void __kprobes disarm_all_kprobes(void)
1824 struct hlist_head *head;
1825 struct hlist_node *node;
1829 mutex_lock(&kprobe_mutex);
1831 /* If kprobes are already disarmed, just return */
1832 if (kprobes_all_disarmed)
1833 goto already_disabled;
1835 kprobes_all_disarmed = true;
1836 printk(KERN_INFO "Kprobes globally disabled\n");
1839 * Here we call get_online_cpus() for avoiding text_mutex deadlock,
1840 * because disarming may also unoptimize kprobes.
1843 mutex_lock(&text_mutex);
1844 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1845 head = &kprobe_table[i];
1846 hlist_for_each_entry_rcu(p, node, head, hlist) {
1847 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
1852 mutex_unlock(&text_mutex);
1854 mutex_unlock(&kprobe_mutex);
1855 /* Allow all currently running kprobes to complete */
1856 synchronize_sched();
1860 mutex_unlock(&kprobe_mutex);
1865 * XXX: The debugfs bool file interface doesn't allow for callbacks
1866 * when the bool state is switched. We can reuse that facility when
1869 static ssize_t read_enabled_file_bool(struct file *file,
1870 char __user *user_buf, size_t count, loff_t *ppos)
1874 if (!kprobes_all_disarmed)
1880 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
1883 static ssize_t write_enabled_file_bool(struct file *file,
1884 const char __user *user_buf, size_t count, loff_t *ppos)
1889 buf_size = min(count, (sizeof(buf)-1));
1890 if (copy_from_user(buf, user_buf, buf_size))
1902 disarm_all_kprobes();
1909 static const struct file_operations fops_kp = {
1910 .read = read_enabled_file_bool,
1911 .write = write_enabled_file_bool,
1914 static int __kprobes debugfs_kprobe_init(void)
1916 struct dentry *dir, *file;
1917 unsigned int value = 1;
1919 dir = debugfs_create_dir("kprobes", NULL);
1923 file = debugfs_create_file("list", 0444, dir, NULL,
1924 &debugfs_kprobes_operations);
1926 debugfs_remove(dir);
1930 file = debugfs_create_file("enabled", 0600, dir,
1933 debugfs_remove(dir);
1940 late_initcall(debugfs_kprobe_init);
1941 #endif /* CONFIG_DEBUG_FS */
1943 module_init(init_kprobes);
1945 /* defined in arch/.../kernel/kprobes.c */
1946 EXPORT_SYMBOL_GPL(jprobe_return);