Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6/kvm.git] / kernel / kprobes.c
blob77981813a1e75d6c3c830dac5084bc37e47c1080
1 /*
2 * Kernel Probes (KProbes)
3 * kernel/kprobes.c
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
23 * Rusty Russell).
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
30 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
32 * <prasanna@in.ibm.com> added function-return probes.
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/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-generic/sections.h>
53 #include <asm/cacheflush.h>
54 #include <asm/errno.h>
55 #include <asm/uaccess.h>
57 #define KPROBE_HASH_BITS 6
58 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
62 * Some oddball architectures like 64bit powerpc have function descriptors
63 * so this must be overridable.
65 #ifndef kprobe_lookup_name
66 #define kprobe_lookup_name(name, addr) \
67 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
68 #endif
70 static int kprobes_initialized;
71 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
72 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
74 /* NOTE: change this value only with kprobe_mutex held */
75 static bool kprobes_all_disarmed;
77 /* This protects kprobe_table and optimizing_list */
78 static DEFINE_MUTEX(kprobe_mutex);
79 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
80 static struct {
81 spinlock_t lock ____cacheline_aligned_in_smp;
82 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
84 static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
86 return &(kretprobe_table_locks[hash].lock);
90 * Normally, functions that we'd want to prohibit kprobes in, are marked
91 * __kprobes. But, there are cases where such functions already belong to
92 * a different section (__sched for preempt_schedule)
94 * For such cases, we now have a blacklist
96 static struct kprobe_blackpoint kprobe_blacklist[] = {
97 {"preempt_schedule",},
98 {"native_get_debugreg",},
99 {"irq_entries_start",},
100 {"common_interrupt",},
101 {"mcount",}, /* mcount can be called from everywhere */
102 {NULL} /* Terminator */
105 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
107 * kprobe->ainsn.insn points to the copy of the instruction to be
108 * single-stepped. x86_64, POWER4 and above have no-exec support and
109 * stepping on the instruction on a vmalloced/kmalloced/data page
110 * is a recipe for disaster
112 struct kprobe_insn_page {
113 struct list_head list;
114 kprobe_opcode_t *insns; /* Page of instruction slots */
115 int nused;
116 int ngarbage;
117 char slot_used[];
120 #define KPROBE_INSN_PAGE_SIZE(slots) \
121 (offsetof(struct kprobe_insn_page, slot_used) + \
122 (sizeof(char) * (slots)))
124 struct kprobe_insn_cache {
125 struct list_head pages; /* list of kprobe_insn_page */
126 size_t insn_size; /* size of instruction slot */
127 int nr_garbage;
130 static int slots_per_page(struct kprobe_insn_cache *c)
132 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
135 enum kprobe_slot_state {
136 SLOT_CLEAN = 0,
137 SLOT_DIRTY = 1,
138 SLOT_USED = 2,
141 static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
142 static struct kprobe_insn_cache kprobe_insn_slots = {
143 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
144 .insn_size = MAX_INSN_SIZE,
145 .nr_garbage = 0,
147 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
150 * __get_insn_slot() - Find a slot on an executable page for an instruction.
151 * We allocate an executable page if there's no room on existing ones.
153 static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
155 struct kprobe_insn_page *kip;
157 retry:
158 list_for_each_entry(kip, &c->pages, list) {
159 if (kip->nused < slots_per_page(c)) {
160 int i;
161 for (i = 0; i < slots_per_page(c); i++) {
162 if (kip->slot_used[i] == SLOT_CLEAN) {
163 kip->slot_used[i] = SLOT_USED;
164 kip->nused++;
165 return kip->insns + (i * c->insn_size);
168 /* kip->nused is broken. Fix it. */
169 kip->nused = slots_per_page(c);
170 WARN_ON(1);
174 /* If there are any garbage slots, collect it and try again. */
175 if (c->nr_garbage && collect_garbage_slots(c) == 0)
176 goto retry;
178 /* All out of space. Need to allocate a new page. */
179 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
180 if (!kip)
181 return NULL;
184 * Use module_alloc so this page is within +/- 2GB of where the
185 * kernel image and loaded module images reside. This is required
186 * so x86_64 can correctly handle the %rip-relative fixups.
188 kip->insns = module_alloc(PAGE_SIZE);
189 if (!kip->insns) {
190 kfree(kip);
191 return NULL;
193 INIT_LIST_HEAD(&kip->list);
194 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
195 kip->slot_used[0] = SLOT_USED;
196 kip->nused = 1;
197 kip->ngarbage = 0;
198 list_add(&kip->list, &c->pages);
199 return kip->insns;
203 kprobe_opcode_t __kprobes *get_insn_slot(void)
205 kprobe_opcode_t *ret = NULL;
207 mutex_lock(&kprobe_insn_mutex);
208 ret = __get_insn_slot(&kprobe_insn_slots);
209 mutex_unlock(&kprobe_insn_mutex);
211 return ret;
214 /* Return 1 if all garbages are collected, otherwise 0. */
215 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
217 kip->slot_used[idx] = SLOT_CLEAN;
218 kip->nused--;
219 if (kip->nused == 0) {
221 * Page is no longer in use. Free it unless
222 * it's the last one. We keep the last one
223 * so as not to have to set it up again the
224 * next time somebody inserts a probe.
226 if (!list_is_singular(&kip->list)) {
227 list_del(&kip->list);
228 module_free(NULL, kip->insns);
229 kfree(kip);
231 return 1;
233 return 0;
236 static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
238 struct kprobe_insn_page *kip, *next;
240 /* Ensure no-one is interrupted on the garbages */
241 synchronize_sched();
243 list_for_each_entry_safe(kip, next, &c->pages, list) {
244 int i;
245 if (kip->ngarbage == 0)
246 continue;
247 kip->ngarbage = 0; /* we will collect all garbages */
248 for (i = 0; i < slots_per_page(c); i++) {
249 if (kip->slot_used[i] == SLOT_DIRTY &&
250 collect_one_slot(kip, i))
251 break;
254 c->nr_garbage = 0;
255 return 0;
258 static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
259 kprobe_opcode_t *slot, int dirty)
261 struct kprobe_insn_page *kip;
263 list_for_each_entry(kip, &c->pages, list) {
264 long idx = ((long)slot - (long)kip->insns) /
265 (c->insn_size * sizeof(kprobe_opcode_t));
266 if (idx >= 0 && idx < slots_per_page(c)) {
267 WARN_ON(kip->slot_used[idx] != SLOT_USED);
268 if (dirty) {
269 kip->slot_used[idx] = SLOT_DIRTY;
270 kip->ngarbage++;
271 if (++c->nr_garbage > slots_per_page(c))
272 collect_garbage_slots(c);
273 } else
274 collect_one_slot(kip, idx);
275 return;
278 /* Could not free this slot. */
279 WARN_ON(1);
282 void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
284 mutex_lock(&kprobe_insn_mutex);
285 __free_insn_slot(&kprobe_insn_slots, slot, dirty);
286 mutex_unlock(&kprobe_insn_mutex);
288 #ifdef CONFIG_OPTPROBES
289 /* For optimized_kprobe buffer */
290 static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
291 static struct kprobe_insn_cache kprobe_optinsn_slots = {
292 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
293 /* .insn_size is initialized later */
294 .nr_garbage = 0,
296 /* Get a slot for optimized_kprobe buffer */
297 kprobe_opcode_t __kprobes *get_optinsn_slot(void)
299 kprobe_opcode_t *ret = NULL;
301 mutex_lock(&kprobe_optinsn_mutex);
302 ret = __get_insn_slot(&kprobe_optinsn_slots);
303 mutex_unlock(&kprobe_optinsn_mutex);
305 return ret;
308 void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
310 mutex_lock(&kprobe_optinsn_mutex);
311 __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
312 mutex_unlock(&kprobe_optinsn_mutex);
314 #endif
315 #endif
317 /* We have preemption disabled.. so it is safe to use __ versions */
318 static inline void set_kprobe_instance(struct kprobe *kp)
320 __this_cpu_write(kprobe_instance, kp);
323 static inline void reset_kprobe_instance(void)
325 __this_cpu_write(kprobe_instance, NULL);
329 * This routine is called either:
330 * - under the kprobe_mutex - during kprobe_[un]register()
331 * OR
332 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
334 struct kprobe __kprobes *get_kprobe(void *addr)
336 struct hlist_head *head;
337 struct hlist_node *node;
338 struct kprobe *p;
340 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
341 hlist_for_each_entry_rcu(p, node, head, hlist) {
342 if (p->addr == addr)
343 return p;
346 return NULL;
349 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
351 /* Return true if the kprobe is an aggregator */
352 static inline int kprobe_aggrprobe(struct kprobe *p)
354 return p->pre_handler == aggr_pre_handler;
357 /* Return true(!0) if the kprobe is unused */
358 static inline int kprobe_unused(struct kprobe *p)
360 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
361 list_empty(&p->list);
365 * Keep all fields in the kprobe consistent
367 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
369 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
370 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
373 #ifdef CONFIG_OPTPROBES
374 /* NOTE: change this value only with kprobe_mutex held */
375 static bool kprobes_allow_optimization;
378 * Call all pre_handler on the list, but ignores its return value.
379 * This must be called from arch-dep optimized caller.
381 void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
383 struct kprobe *kp;
385 list_for_each_entry_rcu(kp, &p->list, list) {
386 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
387 set_kprobe_instance(kp);
388 kp->pre_handler(kp, regs);
390 reset_kprobe_instance();
394 /* Free optimized instructions and optimized_kprobe */
395 static __kprobes void free_aggr_kprobe(struct kprobe *p)
397 struct optimized_kprobe *op;
399 op = container_of(p, struct optimized_kprobe, kp);
400 arch_remove_optimized_kprobe(op);
401 arch_remove_kprobe(p);
402 kfree(op);
405 /* Return true(!0) if the kprobe is ready for optimization. */
406 static inline int kprobe_optready(struct kprobe *p)
408 struct optimized_kprobe *op;
410 if (kprobe_aggrprobe(p)) {
411 op = container_of(p, struct optimized_kprobe, kp);
412 return arch_prepared_optinsn(&op->optinsn);
415 return 0;
418 /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
419 static inline int kprobe_disarmed(struct kprobe *p)
421 struct optimized_kprobe *op;
423 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
424 if (!kprobe_aggrprobe(p))
425 return kprobe_disabled(p);
427 op = container_of(p, struct optimized_kprobe, kp);
429 return kprobe_disabled(p) && list_empty(&op->list);
432 /* Return true(!0) if the probe is queued on (un)optimizing lists */
433 static int __kprobes kprobe_queued(struct kprobe *p)
435 struct optimized_kprobe *op;
437 if (kprobe_aggrprobe(p)) {
438 op = container_of(p, struct optimized_kprobe, kp);
439 if (!list_empty(&op->list))
440 return 1;
442 return 0;
446 * Return an optimized kprobe whose optimizing code replaces
447 * instructions including addr (exclude breakpoint).
449 static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
451 int i;
452 struct kprobe *p = NULL;
453 struct optimized_kprobe *op;
455 /* Don't check i == 0, since that is a breakpoint case. */
456 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
457 p = get_kprobe((void *)(addr - i));
459 if (p && kprobe_optready(p)) {
460 op = container_of(p, struct optimized_kprobe, kp);
461 if (arch_within_optimized_kprobe(op, addr))
462 return p;
465 return NULL;
468 /* Optimization staging list, protected by kprobe_mutex */
469 static LIST_HEAD(optimizing_list);
470 static LIST_HEAD(unoptimizing_list);
472 static void kprobe_optimizer(struct work_struct *work);
473 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
474 static DECLARE_COMPLETION(optimizer_comp);
475 #define OPTIMIZE_DELAY 5
478 * Optimize (replace a breakpoint with a jump) kprobes listed on
479 * optimizing_list.
481 static __kprobes void do_optimize_kprobes(void)
483 /* Optimization never be done when disarmed */
484 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
485 list_empty(&optimizing_list))
486 return;
489 * The optimization/unoptimization refers online_cpus via
490 * stop_machine() and cpu-hotplug modifies online_cpus.
491 * And same time, text_mutex will be held in cpu-hotplug and here.
492 * This combination can cause a deadlock (cpu-hotplug try to lock
493 * text_mutex but stop_machine can not be done because online_cpus
494 * has been changed)
495 * To avoid this deadlock, we need to call get_online_cpus()
496 * for preventing cpu-hotplug outside of text_mutex locking.
498 get_online_cpus();
499 mutex_lock(&text_mutex);
500 arch_optimize_kprobes(&optimizing_list);
501 mutex_unlock(&text_mutex);
502 put_online_cpus();
506 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
507 * if need) kprobes listed on unoptimizing_list.
509 static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
511 struct optimized_kprobe *op, *tmp;
513 /* Unoptimization must be done anytime */
514 if (list_empty(&unoptimizing_list))
515 return;
517 /* Ditto to do_optimize_kprobes */
518 get_online_cpus();
519 mutex_lock(&text_mutex);
520 arch_unoptimize_kprobes(&unoptimizing_list, free_list);
521 /* Loop free_list for disarming */
522 list_for_each_entry_safe(op, tmp, free_list, list) {
523 /* Disarm probes if marked disabled */
524 if (kprobe_disabled(&op->kp))
525 arch_disarm_kprobe(&op->kp);
526 if (kprobe_unused(&op->kp)) {
528 * Remove unused probes from hash list. After waiting
529 * for synchronization, these probes are reclaimed.
530 * (reclaiming is done by do_free_cleaned_kprobes.)
532 hlist_del_rcu(&op->kp.hlist);
533 } else
534 list_del_init(&op->list);
536 mutex_unlock(&text_mutex);
537 put_online_cpus();
540 /* Reclaim all kprobes on the free_list */
541 static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
543 struct optimized_kprobe *op, *tmp;
545 list_for_each_entry_safe(op, tmp, free_list, list) {
546 BUG_ON(!kprobe_unused(&op->kp));
547 list_del_init(&op->list);
548 free_aggr_kprobe(&op->kp);
552 /* Start optimizer after OPTIMIZE_DELAY passed */
553 static __kprobes void kick_kprobe_optimizer(void)
555 if (!delayed_work_pending(&optimizing_work))
556 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
559 /* Kprobe jump optimizer */
560 static __kprobes void kprobe_optimizer(struct work_struct *work)
562 LIST_HEAD(free_list);
564 /* Lock modules while optimizing kprobes */
565 mutex_lock(&module_mutex);
566 mutex_lock(&kprobe_mutex);
569 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
570 * kprobes before waiting for quiesence period.
572 do_unoptimize_kprobes(&free_list);
575 * Step 2: Wait for quiesence period to ensure all running interrupts
576 * are done. Because optprobe may modify multiple instructions
577 * there is a chance that Nth instruction is interrupted. In that
578 * case, running interrupt can return to 2nd-Nth byte of jump
579 * instruction. This wait is for avoiding it.
581 synchronize_sched();
583 /* Step 3: Optimize kprobes after quiesence period */
584 do_optimize_kprobes();
586 /* Step 4: Free cleaned kprobes after quiesence period */
587 do_free_cleaned_kprobes(&free_list);
589 mutex_unlock(&kprobe_mutex);
590 mutex_unlock(&module_mutex);
592 /* Step 5: Kick optimizer again if needed */
593 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
594 kick_kprobe_optimizer();
595 else
596 /* Wake up all waiters */
597 complete_all(&optimizer_comp);
600 /* Wait for completing optimization and unoptimization */
601 static __kprobes void wait_for_kprobe_optimizer(void)
603 if (delayed_work_pending(&optimizing_work))
604 wait_for_completion(&optimizer_comp);
607 /* Optimize kprobe if p is ready to be optimized */
608 static __kprobes void optimize_kprobe(struct kprobe *p)
610 struct optimized_kprobe *op;
612 /* Check if the kprobe is disabled or not ready for optimization. */
613 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
614 (kprobe_disabled(p) || kprobes_all_disarmed))
615 return;
617 /* Both of break_handler and post_handler are not supported. */
618 if (p->break_handler || p->post_handler)
619 return;
621 op = container_of(p, struct optimized_kprobe, kp);
623 /* Check there is no other kprobes at the optimized instructions */
624 if (arch_check_optimized_kprobe(op) < 0)
625 return;
627 /* Check if it is already optimized. */
628 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
629 return;
630 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
632 if (!list_empty(&op->list))
633 /* This is under unoptimizing. Just dequeue the probe */
634 list_del_init(&op->list);
635 else {
636 list_add(&op->list, &optimizing_list);
637 kick_kprobe_optimizer();
641 /* Short cut to direct unoptimizing */
642 static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
644 get_online_cpus();
645 arch_unoptimize_kprobe(op);
646 put_online_cpus();
647 if (kprobe_disabled(&op->kp))
648 arch_disarm_kprobe(&op->kp);
651 /* Unoptimize a kprobe if p is optimized */
652 static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
654 struct optimized_kprobe *op;
656 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
657 return; /* This is not an optprobe nor optimized */
659 op = container_of(p, struct optimized_kprobe, kp);
660 if (!kprobe_optimized(p)) {
661 /* Unoptimized or unoptimizing case */
662 if (force && !list_empty(&op->list)) {
664 * Only if this is unoptimizing kprobe and forced,
665 * forcibly unoptimize it. (No need to unoptimize
666 * unoptimized kprobe again :)
668 list_del_init(&op->list);
669 force_unoptimize_kprobe(op);
671 return;
674 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
675 if (!list_empty(&op->list)) {
676 /* Dequeue from the optimization queue */
677 list_del_init(&op->list);
678 return;
680 /* Optimized kprobe case */
681 if (force)
682 /* Forcibly update the code: this is a special case */
683 force_unoptimize_kprobe(op);
684 else {
685 list_add(&op->list, &unoptimizing_list);
686 kick_kprobe_optimizer();
690 /* Cancel unoptimizing for reusing */
691 static void reuse_unused_kprobe(struct kprobe *ap)
693 struct optimized_kprobe *op;
695 BUG_ON(!kprobe_unused(ap));
697 * Unused kprobe MUST be on the way of delayed unoptimizing (means
698 * there is still a relative jump) and disabled.
700 op = container_of(ap, struct optimized_kprobe, kp);
701 if (unlikely(list_empty(&op->list)))
702 printk(KERN_WARNING "Warning: found a stray unused "
703 "aggrprobe@%p\n", ap->addr);
704 /* Enable the probe again */
705 ap->flags &= ~KPROBE_FLAG_DISABLED;
706 /* Optimize it again (remove from op->list) */
707 BUG_ON(!kprobe_optready(ap));
708 optimize_kprobe(ap);
711 /* Remove optimized instructions */
712 static void __kprobes kill_optimized_kprobe(struct kprobe *p)
714 struct optimized_kprobe *op;
716 op = container_of(p, struct optimized_kprobe, kp);
717 if (!list_empty(&op->list))
718 /* Dequeue from the (un)optimization queue */
719 list_del_init(&op->list);
721 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
722 /* Don't touch the code, because it is already freed. */
723 arch_remove_optimized_kprobe(op);
726 /* Try to prepare optimized instructions */
727 static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
729 struct optimized_kprobe *op;
731 op = container_of(p, struct optimized_kprobe, kp);
732 arch_prepare_optimized_kprobe(op);
735 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
736 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
738 struct optimized_kprobe *op;
740 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
741 if (!op)
742 return NULL;
744 INIT_LIST_HEAD(&op->list);
745 op->kp.addr = p->addr;
746 arch_prepare_optimized_kprobe(op);
748 return &op->kp;
751 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
754 * Prepare an optimized_kprobe and optimize it
755 * NOTE: p must be a normal registered kprobe
757 static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
759 struct kprobe *ap;
760 struct optimized_kprobe *op;
762 ap = alloc_aggr_kprobe(p);
763 if (!ap)
764 return;
766 op = container_of(ap, struct optimized_kprobe, kp);
767 if (!arch_prepared_optinsn(&op->optinsn)) {
768 /* If failed to setup optimizing, fallback to kprobe */
769 arch_remove_optimized_kprobe(op);
770 kfree(op);
771 return;
774 init_aggr_kprobe(ap, p);
775 optimize_kprobe(ap);
778 #ifdef CONFIG_SYSCTL
779 /* This should be called with kprobe_mutex locked */
780 static void __kprobes optimize_all_kprobes(void)
782 struct hlist_head *head;
783 struct hlist_node *node;
784 struct kprobe *p;
785 unsigned int i;
787 /* If optimization is already allowed, just return */
788 if (kprobes_allow_optimization)
789 return;
791 kprobes_allow_optimization = true;
792 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
793 head = &kprobe_table[i];
794 hlist_for_each_entry_rcu(p, node, head, hlist)
795 if (!kprobe_disabled(p))
796 optimize_kprobe(p);
798 printk(KERN_INFO "Kprobes globally optimized\n");
801 /* This should be called with kprobe_mutex locked */
802 static void __kprobes unoptimize_all_kprobes(void)
804 struct hlist_head *head;
805 struct hlist_node *node;
806 struct kprobe *p;
807 unsigned int i;
809 /* If optimization is already prohibited, just return */
810 if (!kprobes_allow_optimization)
811 return;
813 kprobes_allow_optimization = false;
814 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
815 head = &kprobe_table[i];
816 hlist_for_each_entry_rcu(p, node, head, hlist) {
817 if (!kprobe_disabled(p))
818 unoptimize_kprobe(p, false);
821 /* Wait for unoptimizing completion */
822 wait_for_kprobe_optimizer();
823 printk(KERN_INFO "Kprobes globally unoptimized\n");
826 int sysctl_kprobes_optimization;
827 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
828 void __user *buffer, size_t *length,
829 loff_t *ppos)
831 int ret;
833 mutex_lock(&kprobe_mutex);
834 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
835 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
837 if (sysctl_kprobes_optimization)
838 optimize_all_kprobes();
839 else
840 unoptimize_all_kprobes();
841 mutex_unlock(&kprobe_mutex);
843 return ret;
845 #endif /* CONFIG_SYSCTL */
847 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
848 static void __kprobes __arm_kprobe(struct kprobe *p)
850 struct kprobe *_p;
852 /* Check collision with other optimized kprobes */
853 _p = get_optimized_kprobe((unsigned long)p->addr);
854 if (unlikely(_p))
855 /* Fallback to unoptimized kprobe */
856 unoptimize_kprobe(_p, true);
858 arch_arm_kprobe(p);
859 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
862 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
863 static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
865 struct kprobe *_p;
867 unoptimize_kprobe(p, false); /* Try to unoptimize */
869 if (!kprobe_queued(p)) {
870 arch_disarm_kprobe(p);
871 /* If another kprobe was blocked, optimize it. */
872 _p = get_optimized_kprobe((unsigned long)p->addr);
873 if (unlikely(_p) && reopt)
874 optimize_kprobe(_p);
876 /* TODO: reoptimize others after unoptimized this probe */
879 #else /* !CONFIG_OPTPROBES */
881 #define optimize_kprobe(p) do {} while (0)
882 #define unoptimize_kprobe(p, f) do {} while (0)
883 #define kill_optimized_kprobe(p) do {} while (0)
884 #define prepare_optimized_kprobe(p) do {} while (0)
885 #define try_to_optimize_kprobe(p) do {} while (0)
886 #define __arm_kprobe(p) arch_arm_kprobe(p)
887 #define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
888 #define kprobe_disarmed(p) kprobe_disabled(p)
889 #define wait_for_kprobe_optimizer() do {} while (0)
891 /* There should be no unused kprobes can be reused without optimization */
892 static void reuse_unused_kprobe(struct kprobe *ap)
894 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
895 BUG_ON(kprobe_unused(ap));
898 static __kprobes void free_aggr_kprobe(struct kprobe *p)
900 arch_remove_kprobe(p);
901 kfree(p);
904 static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
906 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
908 #endif /* CONFIG_OPTPROBES */
910 /* Arm a kprobe with text_mutex */
911 static void __kprobes arm_kprobe(struct kprobe *kp)
914 * Here, since __arm_kprobe() doesn't use stop_machine(),
915 * this doesn't cause deadlock on text_mutex. So, we don't
916 * need get_online_cpus().
918 mutex_lock(&text_mutex);
919 __arm_kprobe(kp);
920 mutex_unlock(&text_mutex);
923 /* Disarm a kprobe with text_mutex */
924 static void __kprobes disarm_kprobe(struct kprobe *kp)
926 /* Ditto */
927 mutex_lock(&text_mutex);
928 __disarm_kprobe(kp, true);
929 mutex_unlock(&text_mutex);
933 * Aggregate handlers for multiple kprobes support - these handlers
934 * take care of invoking the individual kprobe handlers on p->list
936 static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
938 struct kprobe *kp;
940 list_for_each_entry_rcu(kp, &p->list, list) {
941 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
942 set_kprobe_instance(kp);
943 if (kp->pre_handler(kp, regs))
944 return 1;
946 reset_kprobe_instance();
948 return 0;
951 static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
952 unsigned long flags)
954 struct kprobe *kp;
956 list_for_each_entry_rcu(kp, &p->list, list) {
957 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
958 set_kprobe_instance(kp);
959 kp->post_handler(kp, regs, flags);
960 reset_kprobe_instance();
965 static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
966 int trapnr)
968 struct kprobe *cur = __this_cpu_read(kprobe_instance);
971 * if we faulted "during" the execution of a user specified
972 * probe handler, invoke just that probe's fault handler
974 if (cur && cur->fault_handler) {
975 if (cur->fault_handler(cur, regs, trapnr))
976 return 1;
978 return 0;
981 static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
983 struct kprobe *cur = __this_cpu_read(kprobe_instance);
984 int ret = 0;
986 if (cur && cur->break_handler) {
987 if (cur->break_handler(cur, regs))
988 ret = 1;
990 reset_kprobe_instance();
991 return ret;
994 /* Walks the list and increments nmissed count for multiprobe case */
995 void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
997 struct kprobe *kp;
998 if (!kprobe_aggrprobe(p)) {
999 p->nmissed++;
1000 } else {
1001 list_for_each_entry_rcu(kp, &p->list, list)
1002 kp->nmissed++;
1004 return;
1007 void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
1008 struct hlist_head *head)
1010 struct kretprobe *rp = ri->rp;
1012 /* remove rp inst off the rprobe_inst_table */
1013 hlist_del(&ri->hlist);
1014 INIT_HLIST_NODE(&ri->hlist);
1015 if (likely(rp)) {
1016 spin_lock(&rp->lock);
1017 hlist_add_head(&ri->hlist, &rp->free_instances);
1018 spin_unlock(&rp->lock);
1019 } else
1020 /* Unregistering */
1021 hlist_add_head(&ri->hlist, head);
1024 void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
1025 struct hlist_head **head, unsigned long *flags)
1026 __acquires(hlist_lock)
1028 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1029 spinlock_t *hlist_lock;
1031 *head = &kretprobe_inst_table[hash];
1032 hlist_lock = kretprobe_table_lock_ptr(hash);
1033 spin_lock_irqsave(hlist_lock, *flags);
1036 static void __kprobes kretprobe_table_lock(unsigned long hash,
1037 unsigned long *flags)
1038 __acquires(hlist_lock)
1040 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1041 spin_lock_irqsave(hlist_lock, *flags);
1044 void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
1045 unsigned long *flags)
1046 __releases(hlist_lock)
1048 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1049 spinlock_t *hlist_lock;
1051 hlist_lock = kretprobe_table_lock_ptr(hash);
1052 spin_unlock_irqrestore(hlist_lock, *flags);
1055 static void __kprobes kretprobe_table_unlock(unsigned long hash,
1056 unsigned long *flags)
1057 __releases(hlist_lock)
1059 spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1060 spin_unlock_irqrestore(hlist_lock, *flags);
1064 * This function is called from finish_task_switch when task tk becomes dead,
1065 * so that we can recycle any function-return probe instances associated
1066 * with this task. These left over instances represent probed functions
1067 * that have been called but will never return.
1069 void __kprobes kprobe_flush_task(struct task_struct *tk)
1071 struct kretprobe_instance *ri;
1072 struct hlist_head *head, empty_rp;
1073 struct hlist_node *node, *tmp;
1074 unsigned long hash, flags = 0;
1076 if (unlikely(!kprobes_initialized))
1077 /* Early boot. kretprobe_table_locks not yet initialized. */
1078 return;
1080 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1081 head = &kretprobe_inst_table[hash];
1082 kretprobe_table_lock(hash, &flags);
1083 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
1084 if (ri->task == tk)
1085 recycle_rp_inst(ri, &empty_rp);
1087 kretprobe_table_unlock(hash, &flags);
1088 INIT_HLIST_HEAD(&empty_rp);
1089 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
1090 hlist_del(&ri->hlist);
1091 kfree(ri);
1095 static inline void free_rp_inst(struct kretprobe *rp)
1097 struct kretprobe_instance *ri;
1098 struct hlist_node *pos, *next;
1100 hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
1101 hlist_del(&ri->hlist);
1102 kfree(ri);
1106 static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
1108 unsigned long flags, hash;
1109 struct kretprobe_instance *ri;
1110 struct hlist_node *pos, *next;
1111 struct hlist_head *head;
1113 /* No race here */
1114 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1115 kretprobe_table_lock(hash, &flags);
1116 head = &kretprobe_inst_table[hash];
1117 hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
1118 if (ri->rp == rp)
1119 ri->rp = NULL;
1121 kretprobe_table_unlock(hash, &flags);
1123 free_rp_inst(rp);
1127 * Add the new probe to ap->list. Fail if this is the
1128 * second jprobe at the address - two jprobes can't coexist
1130 static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1132 BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
1134 if (p->break_handler || p->post_handler)
1135 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
1137 if (p->break_handler) {
1138 if (ap->break_handler)
1139 return -EEXIST;
1140 list_add_tail_rcu(&p->list, &ap->list);
1141 ap->break_handler = aggr_break_handler;
1142 } else
1143 list_add_rcu(&p->list, &ap->list);
1144 if (p->post_handler && !ap->post_handler)
1145 ap->post_handler = aggr_post_handler;
1147 if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
1148 ap->flags &= ~KPROBE_FLAG_DISABLED;
1149 if (!kprobes_all_disarmed)
1150 /* Arm the breakpoint again. */
1151 __arm_kprobe(ap);
1153 return 0;
1157 * Fill in the required fields of the "manager kprobe". Replace the
1158 * earlier kprobe in the hlist with the manager kprobe
1160 static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1162 /* Copy p's insn slot to ap */
1163 copy_kprobe(p, ap);
1164 flush_insn_slot(ap);
1165 ap->addr = p->addr;
1166 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1167 ap->pre_handler = aggr_pre_handler;
1168 ap->fault_handler = aggr_fault_handler;
1169 /* We don't care the kprobe which has gone. */
1170 if (p->post_handler && !kprobe_gone(p))
1171 ap->post_handler = aggr_post_handler;
1172 if (p->break_handler && !kprobe_gone(p))
1173 ap->break_handler = aggr_break_handler;
1175 INIT_LIST_HEAD(&ap->list);
1176 INIT_HLIST_NODE(&ap->hlist);
1178 list_add_rcu(&p->list, &ap->list);
1179 hlist_replace_rcu(&p->hlist, &ap->hlist);
1183 * This is the second or subsequent kprobe at the address - handle
1184 * the intricacies
1186 static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
1187 struct kprobe *p)
1189 int ret = 0;
1190 struct kprobe *ap = orig_p;
1192 if (!kprobe_aggrprobe(orig_p)) {
1193 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1194 ap = alloc_aggr_kprobe(orig_p);
1195 if (!ap)
1196 return -ENOMEM;
1197 init_aggr_kprobe(ap, orig_p);
1198 } else if (kprobe_unused(ap))
1199 /* This probe is going to die. Rescue it */
1200 reuse_unused_kprobe(ap);
1202 if (kprobe_gone(ap)) {
1204 * Attempting to insert new probe at the same location that
1205 * had a probe in the module vaddr area which already
1206 * freed. So, the instruction slot has already been
1207 * released. We need a new slot for the new probe.
1209 ret = arch_prepare_kprobe(ap);
1210 if (ret)
1212 * Even if fail to allocate new slot, don't need to
1213 * free aggr_probe. It will be used next time, or
1214 * freed by unregister_kprobe.
1216 return ret;
1218 /* Prepare optimized instructions if possible. */
1219 prepare_optimized_kprobe(ap);
1222 * Clear gone flag to prevent allocating new slot again, and
1223 * set disabled flag because it is not armed yet.
1225 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1226 | KPROBE_FLAG_DISABLED;
1229 /* Copy ap's insn slot to p */
1230 copy_kprobe(ap, p);
1231 return add_new_kprobe(ap, p);
1234 static int __kprobes in_kprobes_functions(unsigned long addr)
1236 struct kprobe_blackpoint *kb;
1238 if (addr >= (unsigned long)__kprobes_text_start &&
1239 addr < (unsigned long)__kprobes_text_end)
1240 return -EINVAL;
1242 * If there exists a kprobe_blacklist, verify and
1243 * fail any probe registration in the prohibited area
1245 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1246 if (kb->start_addr) {
1247 if (addr >= kb->start_addr &&
1248 addr < (kb->start_addr + kb->range))
1249 return -EINVAL;
1252 return 0;
1256 * If we have a symbol_name argument, look it up and add the offset field
1257 * to it. This way, we can specify a relative address to a symbol.
1259 static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
1261 kprobe_opcode_t *addr = p->addr;
1262 if (p->symbol_name) {
1263 if (addr)
1264 return NULL;
1265 kprobe_lookup_name(p->symbol_name, addr);
1268 if (!addr)
1269 return NULL;
1270 return (kprobe_opcode_t *)(((char *)addr) + p->offset);
1273 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1274 static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1276 struct kprobe *ap, *list_p;
1278 ap = get_kprobe(p->addr);
1279 if (unlikely(!ap))
1280 return NULL;
1282 if (p != ap) {
1283 list_for_each_entry_rcu(list_p, &ap->list, list)
1284 if (list_p == p)
1285 /* kprobe p is a valid probe */
1286 goto valid;
1287 return NULL;
1289 valid:
1290 return ap;
1293 /* Return error if the kprobe is being re-registered */
1294 static inline int check_kprobe_rereg(struct kprobe *p)
1296 int ret = 0;
1298 mutex_lock(&kprobe_mutex);
1299 if (__get_valid_kprobe(p))
1300 ret = -EINVAL;
1301 mutex_unlock(&kprobe_mutex);
1303 return ret;
1306 int __kprobes register_kprobe(struct kprobe *p)
1308 int ret = 0;
1309 struct kprobe *old_p;
1310 struct module *probed_mod;
1311 kprobe_opcode_t *addr;
1313 addr = kprobe_addr(p);
1314 if (!addr)
1315 return -EINVAL;
1316 p->addr = addr;
1318 ret = check_kprobe_rereg(p);
1319 if (ret)
1320 return ret;
1322 jump_label_lock();
1323 preempt_disable();
1324 if (!kernel_text_address((unsigned long) p->addr) ||
1325 in_kprobes_functions((unsigned long) p->addr) ||
1326 ftrace_text_reserved(p->addr, p->addr) ||
1327 jump_label_text_reserved(p->addr, p->addr))
1328 goto fail_with_jump_label;
1330 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1331 p->flags &= KPROBE_FLAG_DISABLED;
1334 * Check if are we probing a module.
1336 probed_mod = __module_text_address((unsigned long) p->addr);
1337 if (probed_mod) {
1339 * We must hold a refcount of the probed module while updating
1340 * its code to prohibit unexpected unloading.
1342 if (unlikely(!try_module_get(probed_mod)))
1343 goto fail_with_jump_label;
1346 * If the module freed .init.text, we couldn't insert
1347 * kprobes in there.
1349 if (within_module_init((unsigned long)p->addr, probed_mod) &&
1350 probed_mod->state != MODULE_STATE_COMING) {
1351 module_put(probed_mod);
1352 goto fail_with_jump_label;
1355 preempt_enable();
1356 jump_label_unlock();
1358 p->nmissed = 0;
1359 INIT_LIST_HEAD(&p->list);
1360 mutex_lock(&kprobe_mutex);
1362 jump_label_lock(); /* needed to call jump_label_text_reserved() */
1364 get_online_cpus(); /* For avoiding text_mutex deadlock. */
1365 mutex_lock(&text_mutex);
1367 old_p = get_kprobe(p->addr);
1368 if (old_p) {
1369 /* Since this may unoptimize old_p, locking text_mutex. */
1370 ret = register_aggr_kprobe(old_p, p);
1371 goto out;
1374 ret = arch_prepare_kprobe(p);
1375 if (ret)
1376 goto out;
1378 INIT_HLIST_NODE(&p->hlist);
1379 hlist_add_head_rcu(&p->hlist,
1380 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1382 if (!kprobes_all_disarmed && !kprobe_disabled(p))
1383 __arm_kprobe(p);
1385 /* Try to optimize kprobe */
1386 try_to_optimize_kprobe(p);
1388 out:
1389 mutex_unlock(&text_mutex);
1390 put_online_cpus();
1391 jump_label_unlock();
1392 mutex_unlock(&kprobe_mutex);
1394 if (probed_mod)
1395 module_put(probed_mod);
1397 return ret;
1399 fail_with_jump_label:
1400 preempt_enable();
1401 jump_label_unlock();
1402 return -EINVAL;
1404 EXPORT_SYMBOL_GPL(register_kprobe);
1406 /* Check if all probes on the aggrprobe are disabled */
1407 static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
1409 struct kprobe *kp;
1411 list_for_each_entry_rcu(kp, &ap->list, list)
1412 if (!kprobe_disabled(kp))
1414 * There is an active probe on the list.
1415 * We can't disable this ap.
1417 return 0;
1419 return 1;
1422 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1423 static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
1425 struct kprobe *orig_p;
1427 /* Get an original kprobe for return */
1428 orig_p = __get_valid_kprobe(p);
1429 if (unlikely(orig_p == NULL))
1430 return NULL;
1432 if (!kprobe_disabled(p)) {
1433 /* Disable probe if it is a child probe */
1434 if (p != orig_p)
1435 p->flags |= KPROBE_FLAG_DISABLED;
1437 /* Try to disarm and disable this/parent probe */
1438 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1439 disarm_kprobe(orig_p);
1440 orig_p->flags |= KPROBE_FLAG_DISABLED;
1444 return orig_p;
1448 * Unregister a kprobe without a scheduler synchronization.
1450 static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1452 struct kprobe *ap, *list_p;
1454 /* Disable kprobe. This will disarm it if needed. */
1455 ap = __disable_kprobe(p);
1456 if (ap == NULL)
1457 return -EINVAL;
1459 if (ap == p)
1461 * This probe is an independent(and non-optimized) kprobe
1462 * (not an aggrprobe). Remove from the hash list.
1464 goto disarmed;
1466 /* Following process expects this probe is an aggrprobe */
1467 WARN_ON(!kprobe_aggrprobe(ap));
1469 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1471 * !disarmed could be happen if the probe is under delayed
1472 * unoptimizing.
1474 goto disarmed;
1475 else {
1476 /* If disabling probe has special handlers, update aggrprobe */
1477 if (p->break_handler && !kprobe_gone(p))
1478 ap->break_handler = NULL;
1479 if (p->post_handler && !kprobe_gone(p)) {
1480 list_for_each_entry_rcu(list_p, &ap->list, list) {
1481 if ((list_p != p) && (list_p->post_handler))
1482 goto noclean;
1484 ap->post_handler = NULL;
1486 noclean:
1488 * Remove from the aggrprobe: this path will do nothing in
1489 * __unregister_kprobe_bottom().
1491 list_del_rcu(&p->list);
1492 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1494 * Try to optimize this probe again, because post
1495 * handler may have been changed.
1497 optimize_kprobe(ap);
1499 return 0;
1501 disarmed:
1502 BUG_ON(!kprobe_disarmed(ap));
1503 hlist_del_rcu(&ap->hlist);
1504 return 0;
1507 static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1509 struct kprobe *ap;
1511 if (list_empty(&p->list))
1512 /* This is an independent kprobe */
1513 arch_remove_kprobe(p);
1514 else if (list_is_singular(&p->list)) {
1515 /* This is the last child of an aggrprobe */
1516 ap = list_entry(p->list.next, struct kprobe, list);
1517 list_del(&p->list);
1518 free_aggr_kprobe(ap);
1520 /* Otherwise, do nothing. */
1523 int __kprobes register_kprobes(struct kprobe **kps, int num)
1525 int i, ret = 0;
1527 if (num <= 0)
1528 return -EINVAL;
1529 for (i = 0; i < num; i++) {
1530 ret = register_kprobe(kps[i]);
1531 if (ret < 0) {
1532 if (i > 0)
1533 unregister_kprobes(kps, i);
1534 break;
1537 return ret;
1539 EXPORT_SYMBOL_GPL(register_kprobes);
1541 void __kprobes unregister_kprobe(struct kprobe *p)
1543 unregister_kprobes(&p, 1);
1545 EXPORT_SYMBOL_GPL(unregister_kprobe);
1547 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1549 int i;
1551 if (num <= 0)
1552 return;
1553 mutex_lock(&kprobe_mutex);
1554 for (i = 0; i < num; i++)
1555 if (__unregister_kprobe_top(kps[i]) < 0)
1556 kps[i]->addr = NULL;
1557 mutex_unlock(&kprobe_mutex);
1559 synchronize_sched();
1560 for (i = 0; i < num; i++)
1561 if (kps[i]->addr)
1562 __unregister_kprobe_bottom(kps[i]);
1564 EXPORT_SYMBOL_GPL(unregister_kprobes);
1566 static struct notifier_block kprobe_exceptions_nb = {
1567 .notifier_call = kprobe_exceptions_notify,
1568 .priority = 0x7fffffff /* we need to be notified first */
1571 unsigned long __weak arch_deref_entry_point(void *entry)
1573 return (unsigned long)entry;
1576 int __kprobes register_jprobes(struct jprobe **jps, int num)
1578 struct jprobe *jp;
1579 int ret = 0, i;
1581 if (num <= 0)
1582 return -EINVAL;
1583 for (i = 0; i < num; i++) {
1584 unsigned long addr, offset;
1585 jp = jps[i];
1586 addr = arch_deref_entry_point(jp->entry);
1588 /* Verify probepoint is a function entry point */
1589 if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1590 offset == 0) {
1591 jp->kp.pre_handler = setjmp_pre_handler;
1592 jp->kp.break_handler = longjmp_break_handler;
1593 ret = register_kprobe(&jp->kp);
1594 } else
1595 ret = -EINVAL;
1597 if (ret < 0) {
1598 if (i > 0)
1599 unregister_jprobes(jps, i);
1600 break;
1603 return ret;
1605 EXPORT_SYMBOL_GPL(register_jprobes);
1607 int __kprobes register_jprobe(struct jprobe *jp)
1609 return register_jprobes(&jp, 1);
1611 EXPORT_SYMBOL_GPL(register_jprobe);
1613 void __kprobes unregister_jprobe(struct jprobe *jp)
1615 unregister_jprobes(&jp, 1);
1617 EXPORT_SYMBOL_GPL(unregister_jprobe);
1619 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1621 int i;
1623 if (num <= 0)
1624 return;
1625 mutex_lock(&kprobe_mutex);
1626 for (i = 0; i < num; i++)
1627 if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1628 jps[i]->kp.addr = NULL;
1629 mutex_unlock(&kprobe_mutex);
1631 synchronize_sched();
1632 for (i = 0; i < num; i++) {
1633 if (jps[i]->kp.addr)
1634 __unregister_kprobe_bottom(&jps[i]->kp);
1637 EXPORT_SYMBOL_GPL(unregister_jprobes);
1639 #ifdef CONFIG_KRETPROBES
1641 * This kprobe pre_handler is registered with every kretprobe. When probe
1642 * hits it will set up the return probe.
1644 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1645 struct pt_regs *regs)
1647 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1648 unsigned long hash, flags = 0;
1649 struct kretprobe_instance *ri;
1651 /*TODO: consider to only swap the RA after the last pre_handler fired */
1652 hash = hash_ptr(current, KPROBE_HASH_BITS);
1653 spin_lock_irqsave(&rp->lock, flags);
1654 if (!hlist_empty(&rp->free_instances)) {
1655 ri = hlist_entry(rp->free_instances.first,
1656 struct kretprobe_instance, hlist);
1657 hlist_del(&ri->hlist);
1658 spin_unlock_irqrestore(&rp->lock, flags);
1660 ri->rp = rp;
1661 ri->task = current;
1663 if (rp->entry_handler && rp->entry_handler(ri, regs))
1664 return 0;
1666 arch_prepare_kretprobe(ri, regs);
1668 /* XXX(hch): why is there no hlist_move_head? */
1669 INIT_HLIST_NODE(&ri->hlist);
1670 kretprobe_table_lock(hash, &flags);
1671 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1672 kretprobe_table_unlock(hash, &flags);
1673 } else {
1674 rp->nmissed++;
1675 spin_unlock_irqrestore(&rp->lock, flags);
1677 return 0;
1680 int __kprobes register_kretprobe(struct kretprobe *rp)
1682 int ret = 0;
1683 struct kretprobe_instance *inst;
1684 int i;
1685 void *addr;
1687 if (kretprobe_blacklist_size) {
1688 addr = kprobe_addr(&rp->kp);
1689 if (!addr)
1690 return -EINVAL;
1692 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1693 if (kretprobe_blacklist[i].addr == addr)
1694 return -EINVAL;
1698 rp->kp.pre_handler = pre_handler_kretprobe;
1699 rp->kp.post_handler = NULL;
1700 rp->kp.fault_handler = NULL;
1701 rp->kp.break_handler = NULL;
1703 /* Pre-allocate memory for max kretprobe instances */
1704 if (rp->maxactive <= 0) {
1705 #ifdef CONFIG_PREEMPT
1706 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1707 #else
1708 rp->maxactive = num_possible_cpus();
1709 #endif
1711 spin_lock_init(&rp->lock);
1712 INIT_HLIST_HEAD(&rp->free_instances);
1713 for (i = 0; i < rp->maxactive; i++) {
1714 inst = kmalloc(sizeof(struct kretprobe_instance) +
1715 rp->data_size, GFP_KERNEL);
1716 if (inst == NULL) {
1717 free_rp_inst(rp);
1718 return -ENOMEM;
1720 INIT_HLIST_NODE(&inst->hlist);
1721 hlist_add_head(&inst->hlist, &rp->free_instances);
1724 rp->nmissed = 0;
1725 /* Establish function entry probe point */
1726 ret = register_kprobe(&rp->kp);
1727 if (ret != 0)
1728 free_rp_inst(rp);
1729 return ret;
1731 EXPORT_SYMBOL_GPL(register_kretprobe);
1733 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1735 int ret = 0, i;
1737 if (num <= 0)
1738 return -EINVAL;
1739 for (i = 0; i < num; i++) {
1740 ret = register_kretprobe(rps[i]);
1741 if (ret < 0) {
1742 if (i > 0)
1743 unregister_kretprobes(rps, i);
1744 break;
1747 return ret;
1749 EXPORT_SYMBOL_GPL(register_kretprobes);
1751 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1753 unregister_kretprobes(&rp, 1);
1755 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1757 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1759 int i;
1761 if (num <= 0)
1762 return;
1763 mutex_lock(&kprobe_mutex);
1764 for (i = 0; i < num; i++)
1765 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1766 rps[i]->kp.addr = NULL;
1767 mutex_unlock(&kprobe_mutex);
1769 synchronize_sched();
1770 for (i = 0; i < num; i++) {
1771 if (rps[i]->kp.addr) {
1772 __unregister_kprobe_bottom(&rps[i]->kp);
1773 cleanup_rp_inst(rps[i]);
1777 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1779 #else /* CONFIG_KRETPROBES */
1780 int __kprobes register_kretprobe(struct kretprobe *rp)
1782 return -ENOSYS;
1784 EXPORT_SYMBOL_GPL(register_kretprobe);
1786 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1788 return -ENOSYS;
1790 EXPORT_SYMBOL_GPL(register_kretprobes);
1792 void __kprobes unregister_kretprobe(struct kretprobe *rp)
1795 EXPORT_SYMBOL_GPL(unregister_kretprobe);
1797 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1800 EXPORT_SYMBOL_GPL(unregister_kretprobes);
1802 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1803 struct pt_regs *regs)
1805 return 0;
1808 #endif /* CONFIG_KRETPROBES */
1810 /* Set the kprobe gone and remove its instruction buffer. */
1811 static void __kprobes kill_kprobe(struct kprobe *p)
1813 struct kprobe *kp;
1815 p->flags |= KPROBE_FLAG_GONE;
1816 if (kprobe_aggrprobe(p)) {
1818 * If this is an aggr_kprobe, we have to list all the
1819 * chained probes and mark them GONE.
1821 list_for_each_entry_rcu(kp, &p->list, list)
1822 kp->flags |= KPROBE_FLAG_GONE;
1823 p->post_handler = NULL;
1824 p->break_handler = NULL;
1825 kill_optimized_kprobe(p);
1828 * Here, we can remove insn_slot safely, because no thread calls
1829 * the original probed function (which will be freed soon) any more.
1831 arch_remove_kprobe(p);
1834 /* Disable one kprobe */
1835 int __kprobes disable_kprobe(struct kprobe *kp)
1837 int ret = 0;
1839 mutex_lock(&kprobe_mutex);
1841 /* Disable this kprobe */
1842 if (__disable_kprobe(kp) == NULL)
1843 ret = -EINVAL;
1845 mutex_unlock(&kprobe_mutex);
1846 return ret;
1848 EXPORT_SYMBOL_GPL(disable_kprobe);
1850 /* Enable one kprobe */
1851 int __kprobes enable_kprobe(struct kprobe *kp)
1853 int ret = 0;
1854 struct kprobe *p;
1856 mutex_lock(&kprobe_mutex);
1858 /* Check whether specified probe is valid. */
1859 p = __get_valid_kprobe(kp);
1860 if (unlikely(p == NULL)) {
1861 ret = -EINVAL;
1862 goto out;
1865 if (kprobe_gone(kp)) {
1866 /* This kprobe has gone, we couldn't enable it. */
1867 ret = -EINVAL;
1868 goto out;
1871 if (p != kp)
1872 kp->flags &= ~KPROBE_FLAG_DISABLED;
1874 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1875 p->flags &= ~KPROBE_FLAG_DISABLED;
1876 arm_kprobe(p);
1878 out:
1879 mutex_unlock(&kprobe_mutex);
1880 return ret;
1882 EXPORT_SYMBOL_GPL(enable_kprobe);
1884 void __kprobes dump_kprobe(struct kprobe *kp)
1886 printk(KERN_WARNING "Dumping kprobe:\n");
1887 printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1888 kp->symbol_name, kp->addr, kp->offset);
1891 /* Module notifier call back, checking kprobes on the module */
1892 static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1893 unsigned long val, void *data)
1895 struct module *mod = data;
1896 struct hlist_head *head;
1897 struct hlist_node *node;
1898 struct kprobe *p;
1899 unsigned int i;
1900 int checkcore = (val == MODULE_STATE_GOING);
1902 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1903 return NOTIFY_DONE;
1906 * When MODULE_STATE_GOING was notified, both of module .text and
1907 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1908 * notified, only .init.text section would be freed. We need to
1909 * disable kprobes which have been inserted in the sections.
1911 mutex_lock(&kprobe_mutex);
1912 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1913 head = &kprobe_table[i];
1914 hlist_for_each_entry_rcu(p, node, head, hlist)
1915 if (within_module_init((unsigned long)p->addr, mod) ||
1916 (checkcore &&
1917 within_module_core((unsigned long)p->addr, mod))) {
1919 * The vaddr this probe is installed will soon
1920 * be vfreed buy not synced to disk. Hence,
1921 * disarming the breakpoint isn't needed.
1923 kill_kprobe(p);
1926 mutex_unlock(&kprobe_mutex);
1927 return NOTIFY_DONE;
1930 static struct notifier_block kprobe_module_nb = {
1931 .notifier_call = kprobes_module_callback,
1932 .priority = 0
1935 static int __init init_kprobes(void)
1937 int i, err = 0;
1938 unsigned long offset = 0, size = 0;
1939 char *modname, namebuf[128];
1940 const char *symbol_name;
1941 void *addr;
1942 struct kprobe_blackpoint *kb;
1944 /* FIXME allocate the probe table, currently defined statically */
1945 /* initialize all list heads */
1946 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1947 INIT_HLIST_HEAD(&kprobe_table[i]);
1948 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1949 spin_lock_init(&(kretprobe_table_locks[i].lock));
1953 * Lookup and populate the kprobe_blacklist.
1955 * Unlike the kretprobe blacklist, we'll need to determine
1956 * the range of addresses that belong to the said functions,
1957 * since a kprobe need not necessarily be at the beginning
1958 * of a function.
1960 for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1961 kprobe_lookup_name(kb->name, addr);
1962 if (!addr)
1963 continue;
1965 kb->start_addr = (unsigned long)addr;
1966 symbol_name = kallsyms_lookup(kb->start_addr,
1967 &size, &offset, &modname, namebuf);
1968 if (!symbol_name)
1969 kb->range = 0;
1970 else
1971 kb->range = size;
1974 if (kretprobe_blacklist_size) {
1975 /* lookup the function address from its name */
1976 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1977 kprobe_lookup_name(kretprobe_blacklist[i].name,
1978 kretprobe_blacklist[i].addr);
1979 if (!kretprobe_blacklist[i].addr)
1980 printk("kretprobe: lookup failed: %s\n",
1981 kretprobe_blacklist[i].name);
1985 #if defined(CONFIG_OPTPROBES)
1986 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
1987 /* Init kprobe_optinsn_slots */
1988 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
1989 #endif
1990 /* By default, kprobes can be optimized */
1991 kprobes_allow_optimization = true;
1992 #endif
1994 /* By default, kprobes are armed */
1995 kprobes_all_disarmed = false;
1997 err = arch_init_kprobes();
1998 if (!err)
1999 err = register_die_notifier(&kprobe_exceptions_nb);
2000 if (!err)
2001 err = register_module_notifier(&kprobe_module_nb);
2003 kprobes_initialized = (err == 0);
2005 if (!err)
2006 init_test_probes();
2007 return err;
2010 #ifdef CONFIG_DEBUG_FS
2011 static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
2012 const char *sym, int offset, char *modname, struct kprobe *pp)
2014 char *kprobe_type;
2016 if (p->pre_handler == pre_handler_kretprobe)
2017 kprobe_type = "r";
2018 else if (p->pre_handler == setjmp_pre_handler)
2019 kprobe_type = "j";
2020 else
2021 kprobe_type = "k";
2023 if (sym)
2024 seq_printf(pi, "%p %s %s+0x%x %s ",
2025 p->addr, kprobe_type, sym, offset,
2026 (modname ? modname : " "));
2027 else
2028 seq_printf(pi, "%p %s %p ",
2029 p->addr, kprobe_type, p->addr);
2031 if (!pp)
2032 pp = p;
2033 seq_printf(pi, "%s%s%s\n",
2034 (kprobe_gone(p) ? "[GONE]" : ""),
2035 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
2036 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
2039 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2041 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2044 static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2046 (*pos)++;
2047 if (*pos >= KPROBE_TABLE_SIZE)
2048 return NULL;
2049 return pos;
2052 static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
2054 /* Nothing to do */
2057 static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
2059 struct hlist_head *head;
2060 struct hlist_node *node;
2061 struct kprobe *p, *kp;
2062 const char *sym = NULL;
2063 unsigned int i = *(loff_t *) v;
2064 unsigned long offset = 0;
2065 char *modname, namebuf[128];
2067 head = &kprobe_table[i];
2068 preempt_disable();
2069 hlist_for_each_entry_rcu(p, node, head, hlist) {
2070 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2071 &offset, &modname, namebuf);
2072 if (kprobe_aggrprobe(p)) {
2073 list_for_each_entry_rcu(kp, &p->list, list)
2074 report_probe(pi, kp, sym, offset, modname, p);
2075 } else
2076 report_probe(pi, p, sym, offset, modname, NULL);
2078 preempt_enable();
2079 return 0;
2082 static const struct seq_operations kprobes_seq_ops = {
2083 .start = kprobe_seq_start,
2084 .next = kprobe_seq_next,
2085 .stop = kprobe_seq_stop,
2086 .show = show_kprobe_addr
2089 static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
2091 return seq_open(filp, &kprobes_seq_ops);
2094 static const struct file_operations debugfs_kprobes_operations = {
2095 .open = kprobes_open,
2096 .read = seq_read,
2097 .llseek = seq_lseek,
2098 .release = seq_release,
2101 static void __kprobes arm_all_kprobes(void)
2103 struct hlist_head *head;
2104 struct hlist_node *node;
2105 struct kprobe *p;
2106 unsigned int i;
2108 mutex_lock(&kprobe_mutex);
2110 /* If kprobes are armed, just return */
2111 if (!kprobes_all_disarmed)
2112 goto already_enabled;
2114 /* Arming kprobes doesn't optimize kprobe itself */
2115 mutex_lock(&text_mutex);
2116 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2117 head = &kprobe_table[i];
2118 hlist_for_each_entry_rcu(p, node, head, hlist)
2119 if (!kprobe_disabled(p))
2120 __arm_kprobe(p);
2122 mutex_unlock(&text_mutex);
2124 kprobes_all_disarmed = false;
2125 printk(KERN_INFO "Kprobes globally enabled\n");
2127 already_enabled:
2128 mutex_unlock(&kprobe_mutex);
2129 return;
2132 static void __kprobes disarm_all_kprobes(void)
2134 struct hlist_head *head;
2135 struct hlist_node *node;
2136 struct kprobe *p;
2137 unsigned int i;
2139 mutex_lock(&kprobe_mutex);
2141 /* If kprobes are already disarmed, just return */
2142 if (kprobes_all_disarmed) {
2143 mutex_unlock(&kprobe_mutex);
2144 return;
2147 kprobes_all_disarmed = true;
2148 printk(KERN_INFO "Kprobes globally disabled\n");
2150 mutex_lock(&text_mutex);
2151 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2152 head = &kprobe_table[i];
2153 hlist_for_each_entry_rcu(p, node, head, hlist) {
2154 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
2155 __disarm_kprobe(p, false);
2158 mutex_unlock(&text_mutex);
2159 mutex_unlock(&kprobe_mutex);
2161 /* Wait for disarming all kprobes by optimizer */
2162 wait_for_kprobe_optimizer();
2166 * XXX: The debugfs bool file interface doesn't allow for callbacks
2167 * when the bool state is switched. We can reuse that facility when
2168 * available
2170 static ssize_t read_enabled_file_bool(struct file *file,
2171 char __user *user_buf, size_t count, loff_t *ppos)
2173 char buf[3];
2175 if (!kprobes_all_disarmed)
2176 buf[0] = '1';
2177 else
2178 buf[0] = '0';
2179 buf[1] = '\n';
2180 buf[2] = 0x00;
2181 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2184 static ssize_t write_enabled_file_bool(struct file *file,
2185 const char __user *user_buf, size_t count, loff_t *ppos)
2187 char buf[32];
2188 int buf_size;
2190 buf_size = min(count, (sizeof(buf)-1));
2191 if (copy_from_user(buf, user_buf, buf_size))
2192 return -EFAULT;
2194 switch (buf[0]) {
2195 case 'y':
2196 case 'Y':
2197 case '1':
2198 arm_all_kprobes();
2199 break;
2200 case 'n':
2201 case 'N':
2202 case '0':
2203 disarm_all_kprobes();
2204 break;
2207 return count;
2210 static const struct file_operations fops_kp = {
2211 .read = read_enabled_file_bool,
2212 .write = write_enabled_file_bool,
2213 .llseek = default_llseek,
2216 static int __kprobes debugfs_kprobe_init(void)
2218 struct dentry *dir, *file;
2219 unsigned int value = 1;
2221 dir = debugfs_create_dir("kprobes", NULL);
2222 if (!dir)
2223 return -ENOMEM;
2225 file = debugfs_create_file("list", 0444, dir, NULL,
2226 &debugfs_kprobes_operations);
2227 if (!file) {
2228 debugfs_remove(dir);
2229 return -ENOMEM;
2232 file = debugfs_create_file("enabled", 0600, dir,
2233 &value, &fops_kp);
2234 if (!file) {
2235 debugfs_remove(dir);
2236 return -ENOMEM;
2239 return 0;
2242 late_initcall(debugfs_kprobe_init);
2243 #endif /* CONFIG_DEBUG_FS */
2245 module_init(init_kprobes);
2247 /* defined in arch/.../kernel/kprobes.c */
2248 EXPORT_SYMBOL_GPL(jprobe_return);