1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Kernel Probes (KProbes)
6 * Copyright (C) IBM Corporation, 2002, 2004
8 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
9 * Probes initial implementation (includes suggestions from
11 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
12 * hlists and exceptions notifier as suggested by Andi Kleen.
13 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
14 * interface to access function arguments.
15 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
16 * exceptions notifier to be first on the priority list.
17 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
18 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
19 * <prasanna@in.ibm.com> added function-return probes.
21 #include <linux/kprobes.h>
22 #include <linux/hash.h>
23 #include <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/stddef.h>
26 #include <linux/export.h>
27 #include <linux/moduleloader.h>
28 #include <linux/kallsyms.h>
29 #include <linux/freezer.h>
30 #include <linux/seq_file.h>
31 #include <linux/debugfs.h>
32 #include <linux/sysctl.h>
33 #include <linux/kdebug.h>
34 #include <linux/memory.h>
35 #include <linux/ftrace.h>
36 #include <linux/cpu.h>
37 #include <linux/jump_label.h>
38 #include <linux/perf_event.h>
40 #include <asm/sections.h>
41 #include <asm/cacheflush.h>
42 #include <asm/errno.h>
43 #include <linux/uaccess.h>
45 #define KPROBE_HASH_BITS 6
46 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
49 static int kprobes_initialized;
50 /* kprobe_table can be accessed by
51 * - Normal hlist traversal and RCU add/del under kprobe_mutex is held.
53 * - RCU hlist traversal under disabling preempt (breakpoint handlers)
55 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
56 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
58 /* NOTE: change this value only with kprobe_mutex held */
59 static bool kprobes_all_disarmed;
61 /* This protects kprobe_table and optimizing_list */
62 static DEFINE_MUTEX(kprobe_mutex);
63 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
65 raw_spinlock_t lock ____cacheline_aligned_in_smp;
66 } kretprobe_table_locks[KPROBE_TABLE_SIZE];
68 kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
69 unsigned int __unused)
71 return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
74 static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
76 return &(kretprobe_table_locks[hash].lock);
79 /* Blacklist -- list of struct kprobe_blacklist_entry */
80 static LIST_HEAD(kprobe_blacklist);
82 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
84 * kprobe->ainsn.insn points to the copy of the instruction to be
85 * single-stepped. x86_64, POWER4 and above have no-exec support and
86 * stepping on the instruction on a vmalloced/kmalloced/data page
87 * is a recipe for disaster
89 struct kprobe_insn_page {
90 struct list_head list;
91 kprobe_opcode_t *insns; /* Page of instruction slots */
92 struct kprobe_insn_cache *cache;
98 #define KPROBE_INSN_PAGE_SIZE(slots) \
99 (offsetof(struct kprobe_insn_page, slot_used) + \
100 (sizeof(char) * (slots)))
102 static int slots_per_page(struct kprobe_insn_cache *c)
104 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
107 enum kprobe_slot_state {
113 void __weak *alloc_insn_page(void)
115 return module_alloc(PAGE_SIZE);
118 void __weak free_insn_page(void *page)
120 module_memfree(page);
123 struct kprobe_insn_cache kprobe_insn_slots = {
124 .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
125 .alloc = alloc_insn_page,
126 .free = free_insn_page,
127 .sym = KPROBE_INSN_PAGE_SYM,
128 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
129 .insn_size = MAX_INSN_SIZE,
132 static int collect_garbage_slots(struct kprobe_insn_cache *c);
135 * __get_insn_slot() - Find a slot on an executable page for an instruction.
136 * We allocate an executable page if there's no room on existing ones.
138 kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
140 struct kprobe_insn_page *kip;
141 kprobe_opcode_t *slot = NULL;
143 /* Since the slot array is not protected by rcu, we need a mutex */
144 mutex_lock(&c->mutex);
147 list_for_each_entry_rcu(kip, &c->pages, list) {
148 if (kip->nused < slots_per_page(c)) {
150 for (i = 0; i < slots_per_page(c); i++) {
151 if (kip->slot_used[i] == SLOT_CLEAN) {
152 kip->slot_used[i] = SLOT_USED;
154 slot = kip->insns + (i * c->insn_size);
159 /* kip->nused is broken. Fix it. */
160 kip->nused = slots_per_page(c);
166 /* If there are any garbage slots, collect it and try again. */
167 if (c->nr_garbage && collect_garbage_slots(c) == 0)
170 /* All out of space. Need to allocate a new page. */
171 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
176 * Use module_alloc so this page is within +/- 2GB of where the
177 * kernel image and loaded module images reside. This is required
178 * so x86_64 can correctly handle the %rip-relative fixups.
180 kip->insns = c->alloc();
185 INIT_LIST_HEAD(&kip->list);
186 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
187 kip->slot_used[0] = SLOT_USED;
191 list_add_rcu(&kip->list, &c->pages);
194 /* Record the perf ksymbol register event after adding the page */
195 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns,
196 PAGE_SIZE, false, c->sym);
198 mutex_unlock(&c->mutex);
202 /* Return 1 if all garbages are collected, otherwise 0. */
203 static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
205 kip->slot_used[idx] = SLOT_CLEAN;
207 if (kip->nused == 0) {
209 * Page is no longer in use. Free it unless
210 * it's the last one. We keep the last one
211 * so as not to have to set it up again the
212 * next time somebody inserts a probe.
214 if (!list_is_singular(&kip->list)) {
216 * Record perf ksymbol unregister event before removing
219 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
220 (unsigned long)kip->insns, PAGE_SIZE, true,
222 list_del_rcu(&kip->list);
224 kip->cache->free(kip->insns);
232 static int collect_garbage_slots(struct kprobe_insn_cache *c)
234 struct kprobe_insn_page *kip, *next;
236 /* Ensure no-one is interrupted on the garbages */
239 list_for_each_entry_safe(kip, next, &c->pages, list) {
241 if (kip->ngarbage == 0)
243 kip->ngarbage = 0; /* we will collect all garbages */
244 for (i = 0; i < slots_per_page(c); i++) {
245 if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i))
253 void __free_insn_slot(struct kprobe_insn_cache *c,
254 kprobe_opcode_t *slot, int dirty)
256 struct kprobe_insn_page *kip;
259 mutex_lock(&c->mutex);
261 list_for_each_entry_rcu(kip, &c->pages, list) {
262 idx = ((long)slot - (long)kip->insns) /
263 (c->insn_size * sizeof(kprobe_opcode_t));
264 if (idx >= 0 && idx < slots_per_page(c))
267 /* Could not find this slot. */
272 /* Mark and sweep: this may sleep */
274 /* Check double free */
275 WARN_ON(kip->slot_used[idx] != SLOT_USED);
277 kip->slot_used[idx] = SLOT_DIRTY;
279 if (++c->nr_garbage > slots_per_page(c))
280 collect_garbage_slots(c);
282 collect_one_slot(kip, idx);
285 mutex_unlock(&c->mutex);
289 * Check given address is on the page of kprobe instruction slots.
290 * This will be used for checking whether the address on a stack
291 * is on a text area or not.
293 bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
295 struct kprobe_insn_page *kip;
299 list_for_each_entry_rcu(kip, &c->pages, list) {
300 if (addr >= (unsigned long)kip->insns &&
301 addr < (unsigned long)kip->insns + PAGE_SIZE) {
311 int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
312 unsigned long *value, char *type, char *sym)
314 struct kprobe_insn_page *kip;
318 list_for_each_entry_rcu(kip, &c->pages, list) {
321 strlcpy(sym, c->sym, KSYM_NAME_LEN);
323 *value = (unsigned long)kip->insns;
332 #ifdef CONFIG_OPTPROBES
333 /* For optimized_kprobe buffer */
334 struct kprobe_insn_cache kprobe_optinsn_slots = {
335 .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
336 .alloc = alloc_insn_page,
337 .free = free_insn_page,
338 .sym = KPROBE_OPTINSN_PAGE_SYM,
339 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
340 /* .insn_size is initialized later */
346 /* We have preemption disabled.. so it is safe to use __ versions */
347 static inline void set_kprobe_instance(struct kprobe *kp)
349 __this_cpu_write(kprobe_instance, kp);
352 static inline void reset_kprobe_instance(void)
354 __this_cpu_write(kprobe_instance, NULL);
358 * This routine is called either:
359 * - under the kprobe_mutex - during kprobe_[un]register()
361 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
363 struct kprobe *get_kprobe(void *addr)
365 struct hlist_head *head;
368 head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
369 hlist_for_each_entry_rcu(p, head, hlist,
370 lockdep_is_held(&kprobe_mutex)) {
377 NOKPROBE_SYMBOL(get_kprobe);
379 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
381 /* Return true if the kprobe is an aggregator */
382 static inline int kprobe_aggrprobe(struct kprobe *p)
384 return p->pre_handler == aggr_pre_handler;
387 /* Return true(!0) if the kprobe is unused */
388 static inline int kprobe_unused(struct kprobe *p)
390 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
391 list_empty(&p->list);
395 * Keep all fields in the kprobe consistent
397 static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
399 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
400 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
403 #ifdef CONFIG_OPTPROBES
404 /* NOTE: change this value only with kprobe_mutex held */
405 static bool kprobes_allow_optimization;
408 * Call all pre_handler on the list, but ignores its return value.
409 * This must be called from arch-dep optimized caller.
411 void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
415 list_for_each_entry_rcu(kp, &p->list, list) {
416 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
417 set_kprobe_instance(kp);
418 kp->pre_handler(kp, regs);
420 reset_kprobe_instance();
423 NOKPROBE_SYMBOL(opt_pre_handler);
425 /* Free optimized instructions and optimized_kprobe */
426 static void free_aggr_kprobe(struct kprobe *p)
428 struct optimized_kprobe *op;
430 op = container_of(p, struct optimized_kprobe, kp);
431 arch_remove_optimized_kprobe(op);
432 arch_remove_kprobe(p);
436 /* Return true(!0) if the kprobe is ready for optimization. */
437 static inline int kprobe_optready(struct kprobe *p)
439 struct optimized_kprobe *op;
441 if (kprobe_aggrprobe(p)) {
442 op = container_of(p, struct optimized_kprobe, kp);
443 return arch_prepared_optinsn(&op->optinsn);
449 /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
450 static inline int kprobe_disarmed(struct kprobe *p)
452 struct optimized_kprobe *op;
454 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
455 if (!kprobe_aggrprobe(p))
456 return kprobe_disabled(p);
458 op = container_of(p, struct optimized_kprobe, kp);
460 return kprobe_disabled(p) && list_empty(&op->list);
463 /* Return true(!0) if the probe is queued on (un)optimizing lists */
464 static int kprobe_queued(struct kprobe *p)
466 struct optimized_kprobe *op;
468 if (kprobe_aggrprobe(p)) {
469 op = container_of(p, struct optimized_kprobe, kp);
470 if (!list_empty(&op->list))
477 * Return an optimized kprobe whose optimizing code replaces
478 * instructions including addr (exclude breakpoint).
480 static struct kprobe *get_optimized_kprobe(unsigned long addr)
483 struct kprobe *p = NULL;
484 struct optimized_kprobe *op;
486 /* Don't check i == 0, since that is a breakpoint case. */
487 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
488 p = get_kprobe((void *)(addr - i));
490 if (p && kprobe_optready(p)) {
491 op = container_of(p, struct optimized_kprobe, kp);
492 if (arch_within_optimized_kprobe(op, addr))
499 /* Optimization staging list, protected by kprobe_mutex */
500 static LIST_HEAD(optimizing_list);
501 static LIST_HEAD(unoptimizing_list);
502 static LIST_HEAD(freeing_list);
504 static void kprobe_optimizer(struct work_struct *work);
505 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
506 #define OPTIMIZE_DELAY 5
509 * Optimize (replace a breakpoint with a jump) kprobes listed on
512 static void do_optimize_kprobes(void)
514 lockdep_assert_held(&text_mutex);
516 * The optimization/unoptimization refers online_cpus via
517 * stop_machine() and cpu-hotplug modifies online_cpus.
518 * And same time, text_mutex will be held in cpu-hotplug and here.
519 * This combination can cause a deadlock (cpu-hotplug try to lock
520 * text_mutex but stop_machine can not be done because online_cpus
522 * To avoid this deadlock, caller must have locked cpu hotplug
523 * for preventing cpu-hotplug outside of text_mutex locking.
525 lockdep_assert_cpus_held();
527 /* Optimization never be done when disarmed */
528 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
529 list_empty(&optimizing_list))
532 arch_optimize_kprobes(&optimizing_list);
536 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
537 * if need) kprobes listed on unoptimizing_list.
539 static void do_unoptimize_kprobes(void)
541 struct optimized_kprobe *op, *tmp;
543 lockdep_assert_held(&text_mutex);
544 /* See comment in do_optimize_kprobes() */
545 lockdep_assert_cpus_held();
547 /* Unoptimization must be done anytime */
548 if (list_empty(&unoptimizing_list))
551 arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
552 /* Loop free_list for disarming */
553 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
554 /* Switching from detour code to origin */
555 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
556 /* Disarm probes if marked disabled */
557 if (kprobe_disabled(&op->kp))
558 arch_disarm_kprobe(&op->kp);
559 if (kprobe_unused(&op->kp)) {
561 * Remove unused probes from hash list. After waiting
562 * for synchronization, these probes are reclaimed.
563 * (reclaiming is done by do_free_cleaned_kprobes.)
565 hlist_del_rcu(&op->kp.hlist);
567 list_del_init(&op->list);
571 /* Reclaim all kprobes on the free_list */
572 static void do_free_cleaned_kprobes(void)
574 struct optimized_kprobe *op, *tmp;
576 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
577 list_del_init(&op->list);
578 if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
580 * This must not happen, but if there is a kprobe
581 * still in use, keep it on kprobes hash list.
585 free_aggr_kprobe(&op->kp);
589 /* Start optimizer after OPTIMIZE_DELAY passed */
590 static void kick_kprobe_optimizer(void)
592 schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
595 /* Kprobe jump optimizer */
596 static void kprobe_optimizer(struct work_struct *work)
598 mutex_lock(&kprobe_mutex);
600 mutex_lock(&text_mutex);
603 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
604 * kprobes before waiting for quiesence period.
606 do_unoptimize_kprobes();
609 * Step 2: Wait for quiesence period to ensure all potentially
610 * preempted tasks to have normally scheduled. Because optprobe
611 * may modify multiple instructions, there is a chance that Nth
612 * instruction is preempted. In that case, such tasks can return
613 * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
614 * Note that on non-preemptive kernel, this is transparently converted
615 * to synchronoze_sched() to wait for all interrupts to have completed.
617 synchronize_rcu_tasks();
619 /* Step 3: Optimize kprobes after quiesence period */
620 do_optimize_kprobes();
622 /* Step 4: Free cleaned kprobes after quiesence period */
623 do_free_cleaned_kprobes();
625 mutex_unlock(&text_mutex);
628 /* Step 5: Kick optimizer again if needed */
629 if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
630 kick_kprobe_optimizer();
632 mutex_unlock(&kprobe_mutex);
635 /* Wait for completing optimization and unoptimization */
636 void wait_for_kprobe_optimizer(void)
638 mutex_lock(&kprobe_mutex);
640 while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
641 mutex_unlock(&kprobe_mutex);
643 /* this will also make optimizing_work execute immmediately */
644 flush_delayed_work(&optimizing_work);
645 /* @optimizing_work might not have been queued yet, relax */
648 mutex_lock(&kprobe_mutex);
651 mutex_unlock(&kprobe_mutex);
654 static bool optprobe_queued_unopt(struct optimized_kprobe *op)
656 struct optimized_kprobe *_op;
658 list_for_each_entry(_op, &unoptimizing_list, list) {
666 /* Optimize kprobe if p is ready to be optimized */
667 static void optimize_kprobe(struct kprobe *p)
669 struct optimized_kprobe *op;
671 /* Check if the kprobe is disabled or not ready for optimization. */
672 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
673 (kprobe_disabled(p) || kprobes_all_disarmed))
676 /* kprobes with post_handler can not be optimized */
680 op = container_of(p, struct optimized_kprobe, kp);
682 /* Check there is no other kprobes at the optimized instructions */
683 if (arch_check_optimized_kprobe(op) < 0)
686 /* Check if it is already optimized. */
687 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) {
688 if (optprobe_queued_unopt(op)) {
689 /* This is under unoptimizing. Just dequeue the probe */
690 list_del_init(&op->list);
694 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
696 /* On unoptimizing/optimizing_list, op must have OPTIMIZED flag */
697 if (WARN_ON_ONCE(!list_empty(&op->list)))
700 list_add(&op->list, &optimizing_list);
701 kick_kprobe_optimizer();
704 /* Short cut to direct unoptimizing */
705 static void force_unoptimize_kprobe(struct optimized_kprobe *op)
707 lockdep_assert_cpus_held();
708 arch_unoptimize_kprobe(op);
709 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
712 /* Unoptimize a kprobe if p is optimized */
713 static void unoptimize_kprobe(struct kprobe *p, bool force)
715 struct optimized_kprobe *op;
717 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
718 return; /* This is not an optprobe nor optimized */
720 op = container_of(p, struct optimized_kprobe, kp);
721 if (!kprobe_optimized(p))
724 if (!list_empty(&op->list)) {
725 if (optprobe_queued_unopt(op)) {
726 /* Queued in unoptimizing queue */
729 * Forcibly unoptimize the kprobe here, and queue it
730 * in the freeing list for release afterwards.
732 force_unoptimize_kprobe(op);
733 list_move(&op->list, &freeing_list);
736 /* Dequeue from the optimizing queue */
737 list_del_init(&op->list);
738 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
743 /* Optimized kprobe case */
745 /* Forcibly update the code: this is a special case */
746 force_unoptimize_kprobe(op);
748 list_add(&op->list, &unoptimizing_list);
749 kick_kprobe_optimizer();
753 /* Cancel unoptimizing for reusing */
754 static int reuse_unused_kprobe(struct kprobe *ap)
756 struct optimized_kprobe *op;
759 * Unused kprobe MUST be on the way of delayed unoptimizing (means
760 * there is still a relative jump) and disabled.
762 op = container_of(ap, struct optimized_kprobe, kp);
763 WARN_ON_ONCE(list_empty(&op->list));
764 /* Enable the probe again */
765 ap->flags &= ~KPROBE_FLAG_DISABLED;
766 /* Optimize it again (remove from op->list) */
767 if (!kprobe_optready(ap))
774 /* Remove optimized instructions */
775 static void kill_optimized_kprobe(struct kprobe *p)
777 struct optimized_kprobe *op;
779 op = container_of(p, struct optimized_kprobe, kp);
780 if (!list_empty(&op->list))
781 /* Dequeue from the (un)optimization queue */
782 list_del_init(&op->list);
783 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
785 if (kprobe_unused(p)) {
786 /* Enqueue if it is unused */
787 list_add(&op->list, &freeing_list);
789 * Remove unused probes from the hash list. After waiting
790 * for synchronization, this probe is reclaimed.
791 * (reclaiming is done by do_free_cleaned_kprobes().)
793 hlist_del_rcu(&op->kp.hlist);
796 /* Don't touch the code, because it is already freed. */
797 arch_remove_optimized_kprobe(op);
801 void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
803 if (!kprobe_ftrace(p))
804 arch_prepare_optimized_kprobe(op, p);
807 /* Try to prepare optimized instructions */
808 static void prepare_optimized_kprobe(struct kprobe *p)
810 struct optimized_kprobe *op;
812 op = container_of(p, struct optimized_kprobe, kp);
813 __prepare_optimized_kprobe(op, p);
816 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
817 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
819 struct optimized_kprobe *op;
821 op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
825 INIT_LIST_HEAD(&op->list);
826 op->kp.addr = p->addr;
827 __prepare_optimized_kprobe(op, p);
832 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
835 * Prepare an optimized_kprobe and optimize it
836 * NOTE: p must be a normal registered kprobe
838 static void try_to_optimize_kprobe(struct kprobe *p)
841 struct optimized_kprobe *op;
843 /* Impossible to optimize ftrace-based kprobe */
844 if (kprobe_ftrace(p))
847 /* For preparing optimization, jump_label_text_reserved() is called */
850 mutex_lock(&text_mutex);
852 ap = alloc_aggr_kprobe(p);
856 op = container_of(ap, struct optimized_kprobe, kp);
857 if (!arch_prepared_optinsn(&op->optinsn)) {
858 /* If failed to setup optimizing, fallback to kprobe */
859 arch_remove_optimized_kprobe(op);
864 init_aggr_kprobe(ap, p);
865 optimize_kprobe(ap); /* This just kicks optimizer thread */
868 mutex_unlock(&text_mutex);
874 static void optimize_all_kprobes(void)
876 struct hlist_head *head;
880 mutex_lock(&kprobe_mutex);
881 /* If optimization is already allowed, just return */
882 if (kprobes_allow_optimization)
886 kprobes_allow_optimization = true;
887 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
888 head = &kprobe_table[i];
889 hlist_for_each_entry(p, head, hlist)
890 if (!kprobe_disabled(p))
894 printk(KERN_INFO "Kprobes globally optimized\n");
896 mutex_unlock(&kprobe_mutex);
899 static void unoptimize_all_kprobes(void)
901 struct hlist_head *head;
905 mutex_lock(&kprobe_mutex);
906 /* If optimization is already prohibited, just return */
907 if (!kprobes_allow_optimization) {
908 mutex_unlock(&kprobe_mutex);
913 kprobes_allow_optimization = false;
914 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
915 head = &kprobe_table[i];
916 hlist_for_each_entry(p, head, hlist) {
917 if (!kprobe_disabled(p))
918 unoptimize_kprobe(p, false);
922 mutex_unlock(&kprobe_mutex);
924 /* Wait for unoptimizing completion */
925 wait_for_kprobe_optimizer();
926 printk(KERN_INFO "Kprobes globally unoptimized\n");
929 static DEFINE_MUTEX(kprobe_sysctl_mutex);
930 int sysctl_kprobes_optimization;
931 int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
932 void *buffer, size_t *length,
937 mutex_lock(&kprobe_sysctl_mutex);
938 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
939 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
941 if (sysctl_kprobes_optimization)
942 optimize_all_kprobes();
944 unoptimize_all_kprobes();
945 mutex_unlock(&kprobe_sysctl_mutex);
949 #endif /* CONFIG_SYSCTL */
951 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
952 static void __arm_kprobe(struct kprobe *p)
956 /* Check collision with other optimized kprobes */
957 _p = get_optimized_kprobe((unsigned long)p->addr);
959 /* Fallback to unoptimized kprobe */
960 unoptimize_kprobe(_p, true);
963 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
966 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
967 static void __disarm_kprobe(struct kprobe *p, bool reopt)
971 /* Try to unoptimize */
972 unoptimize_kprobe(p, kprobes_all_disarmed);
974 if (!kprobe_queued(p)) {
975 arch_disarm_kprobe(p);
976 /* If another kprobe was blocked, optimize it. */
977 _p = get_optimized_kprobe((unsigned long)p->addr);
978 if (unlikely(_p) && reopt)
981 /* TODO: reoptimize others after unoptimized this probe */
984 #else /* !CONFIG_OPTPROBES */
986 #define optimize_kprobe(p) do {} while (0)
987 #define unoptimize_kprobe(p, f) do {} while (0)
988 #define kill_optimized_kprobe(p) do {} while (0)
989 #define prepare_optimized_kprobe(p) do {} while (0)
990 #define try_to_optimize_kprobe(p) do {} while (0)
991 #define __arm_kprobe(p) arch_arm_kprobe(p)
992 #define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
993 #define kprobe_disarmed(p) kprobe_disabled(p)
994 #define wait_for_kprobe_optimizer() do {} while (0)
996 static int reuse_unused_kprobe(struct kprobe *ap)
999 * If the optimized kprobe is NOT supported, the aggr kprobe is
1000 * released at the same time that the last aggregated kprobe is
1002 * Thus there should be no chance to reuse unused kprobe.
1004 printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
1008 static void free_aggr_kprobe(struct kprobe *p)
1010 arch_remove_kprobe(p);
1014 static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
1016 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
1018 #endif /* CONFIG_OPTPROBES */
1020 #ifdef CONFIG_KPROBES_ON_FTRACE
1021 static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
1022 .func = kprobe_ftrace_handler,
1023 .flags = FTRACE_OPS_FL_SAVE_REGS,
1026 static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
1027 .func = kprobe_ftrace_handler,
1028 .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
1031 static int kprobe_ipmodify_enabled;
1032 static int kprobe_ftrace_enabled;
1034 /* Must ensure p->addr is really on ftrace */
1035 static int prepare_kprobe(struct kprobe *p)
1037 if (!kprobe_ftrace(p))
1038 return arch_prepare_kprobe(p);
1040 return arch_prepare_kprobe_ftrace(p);
1043 /* Caller must lock kprobe_mutex */
1044 static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
1049 ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
1051 pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n",
1057 ret = register_ftrace_function(ops);
1059 pr_debug("Failed to init kprobe-ftrace (%d)\n", ret);
1069 * At this point, sinec ops is not registered, we should be sefe from
1070 * registering empty filter.
1072 ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
1076 static int arm_kprobe_ftrace(struct kprobe *p)
1078 bool ipmodify = (p->post_handler != NULL);
1080 return __arm_kprobe_ftrace(p,
1081 ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
1082 ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
1085 /* Caller must lock kprobe_mutex */
1086 static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
1092 ret = unregister_ftrace_function(ops);
1093 if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret))
1099 ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
1100 WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n",
1105 static int disarm_kprobe_ftrace(struct kprobe *p)
1107 bool ipmodify = (p->post_handler != NULL);
1109 return __disarm_kprobe_ftrace(p,
1110 ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
1111 ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
1113 #else /* !CONFIG_KPROBES_ON_FTRACE */
1114 #define prepare_kprobe(p) arch_prepare_kprobe(p)
1115 #define arm_kprobe_ftrace(p) (-ENODEV)
1116 #define disarm_kprobe_ftrace(p) (-ENODEV)
1119 /* Arm a kprobe with text_mutex */
1120 static int arm_kprobe(struct kprobe *kp)
1122 if (unlikely(kprobe_ftrace(kp)))
1123 return arm_kprobe_ftrace(kp);
1126 mutex_lock(&text_mutex);
1128 mutex_unlock(&text_mutex);
1134 /* Disarm a kprobe with text_mutex */
1135 static int disarm_kprobe(struct kprobe *kp, bool reopt)
1137 if (unlikely(kprobe_ftrace(kp)))
1138 return disarm_kprobe_ftrace(kp);
1141 mutex_lock(&text_mutex);
1142 __disarm_kprobe(kp, reopt);
1143 mutex_unlock(&text_mutex);
1150 * Aggregate handlers for multiple kprobes support - these handlers
1151 * take care of invoking the individual kprobe handlers on p->list
1153 static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
1157 list_for_each_entry_rcu(kp, &p->list, list) {
1158 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
1159 set_kprobe_instance(kp);
1160 if (kp->pre_handler(kp, regs))
1163 reset_kprobe_instance();
1167 NOKPROBE_SYMBOL(aggr_pre_handler);
1169 static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1170 unsigned long flags)
1174 list_for_each_entry_rcu(kp, &p->list, list) {
1175 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
1176 set_kprobe_instance(kp);
1177 kp->post_handler(kp, regs, flags);
1178 reset_kprobe_instance();
1182 NOKPROBE_SYMBOL(aggr_post_handler);
1184 static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
1187 struct kprobe *cur = __this_cpu_read(kprobe_instance);
1190 * if we faulted "during" the execution of a user specified
1191 * probe handler, invoke just that probe's fault handler
1193 if (cur && cur->fault_handler) {
1194 if (cur->fault_handler(cur, regs, trapnr))
1199 NOKPROBE_SYMBOL(aggr_fault_handler);
1201 /* Walks the list and increments nmissed count for multiprobe case */
1202 void kprobes_inc_nmissed_count(struct kprobe *p)
1205 if (!kprobe_aggrprobe(p)) {
1208 list_for_each_entry_rcu(kp, &p->list, list)
1213 NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
1215 void recycle_rp_inst(struct kretprobe_instance *ri,
1216 struct hlist_head *head)
1218 struct kretprobe *rp = ri->rp;
1220 /* remove rp inst off the rprobe_inst_table */
1221 hlist_del(&ri->hlist);
1222 INIT_HLIST_NODE(&ri->hlist);
1224 raw_spin_lock(&rp->lock);
1225 hlist_add_head(&ri->hlist, &rp->free_instances);
1226 raw_spin_unlock(&rp->lock);
1229 hlist_add_head(&ri->hlist, head);
1231 NOKPROBE_SYMBOL(recycle_rp_inst);
1233 void kretprobe_hash_lock(struct task_struct *tsk,
1234 struct hlist_head **head, unsigned long *flags)
1235 __acquires(hlist_lock)
1237 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1238 raw_spinlock_t *hlist_lock;
1240 *head = &kretprobe_inst_table[hash];
1241 hlist_lock = kretprobe_table_lock_ptr(hash);
1242 raw_spin_lock_irqsave(hlist_lock, *flags);
1244 NOKPROBE_SYMBOL(kretprobe_hash_lock);
1246 static void kretprobe_table_lock(unsigned long hash,
1247 unsigned long *flags)
1248 __acquires(hlist_lock)
1250 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1251 raw_spin_lock_irqsave(hlist_lock, *flags);
1253 NOKPROBE_SYMBOL(kretprobe_table_lock);
1255 void kretprobe_hash_unlock(struct task_struct *tsk,
1256 unsigned long *flags)
1257 __releases(hlist_lock)
1259 unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1260 raw_spinlock_t *hlist_lock;
1262 hlist_lock = kretprobe_table_lock_ptr(hash);
1263 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1265 NOKPROBE_SYMBOL(kretprobe_hash_unlock);
1267 static void kretprobe_table_unlock(unsigned long hash,
1268 unsigned long *flags)
1269 __releases(hlist_lock)
1271 raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1272 raw_spin_unlock_irqrestore(hlist_lock, *flags);
1274 NOKPROBE_SYMBOL(kretprobe_table_unlock);
1276 struct kprobe kprobe_busy = {
1277 .addr = (void *) get_kprobe,
1280 void kprobe_busy_begin(void)
1282 struct kprobe_ctlblk *kcb;
1285 __this_cpu_write(current_kprobe, &kprobe_busy);
1286 kcb = get_kprobe_ctlblk();
1287 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
1290 void kprobe_busy_end(void)
1292 __this_cpu_write(current_kprobe, NULL);
1297 * This function is called from finish_task_switch when task tk becomes dead,
1298 * so that we can recycle any function-return probe instances associated
1299 * with this task. These left over instances represent probed functions
1300 * that have been called but will never return.
1302 void kprobe_flush_task(struct task_struct *tk)
1304 struct kretprobe_instance *ri;
1305 struct hlist_head *head, empty_rp;
1306 struct hlist_node *tmp;
1307 unsigned long hash, flags = 0;
1309 if (unlikely(!kprobes_initialized))
1310 /* Early boot. kretprobe_table_locks not yet initialized. */
1313 kprobe_busy_begin();
1315 INIT_HLIST_HEAD(&empty_rp);
1316 hash = hash_ptr(tk, KPROBE_HASH_BITS);
1317 head = &kretprobe_inst_table[hash];
1318 kretprobe_table_lock(hash, &flags);
1319 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
1321 recycle_rp_inst(ri, &empty_rp);
1323 kretprobe_table_unlock(hash, &flags);
1324 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
1325 hlist_del(&ri->hlist);
1331 NOKPROBE_SYMBOL(kprobe_flush_task);
1333 static inline void free_rp_inst(struct kretprobe *rp)
1335 struct kretprobe_instance *ri;
1336 struct hlist_node *next;
1338 hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) {
1339 hlist_del(&ri->hlist);
1344 static void cleanup_rp_inst(struct kretprobe *rp)
1346 unsigned long flags, hash;
1347 struct kretprobe_instance *ri;
1348 struct hlist_node *next;
1349 struct hlist_head *head;
1352 for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1353 kretprobe_table_lock(hash, &flags);
1354 head = &kretprobe_inst_table[hash];
1355 hlist_for_each_entry_safe(ri, next, head, hlist) {
1359 kretprobe_table_unlock(hash, &flags);
1363 NOKPROBE_SYMBOL(cleanup_rp_inst);
1365 /* Add the new probe to ap->list */
1366 static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1368 if (p->post_handler)
1369 unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
1371 list_add_rcu(&p->list, &ap->list);
1372 if (p->post_handler && !ap->post_handler)
1373 ap->post_handler = aggr_post_handler;
1379 * Fill in the required fields of the "manager kprobe". Replace the
1380 * earlier kprobe in the hlist with the manager kprobe
1382 static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1384 /* Copy p's insn slot to ap */
1386 flush_insn_slot(ap);
1388 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1389 ap->pre_handler = aggr_pre_handler;
1390 ap->fault_handler = aggr_fault_handler;
1391 /* We don't care the kprobe which has gone. */
1392 if (p->post_handler && !kprobe_gone(p))
1393 ap->post_handler = aggr_post_handler;
1395 INIT_LIST_HEAD(&ap->list);
1396 INIT_HLIST_NODE(&ap->hlist);
1398 list_add_rcu(&p->list, &ap->list);
1399 hlist_replace_rcu(&p->hlist, &ap->hlist);
1403 * This is the second or subsequent kprobe at the address - handle
1406 static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
1409 struct kprobe *ap = orig_p;
1413 /* For preparing optimization, jump_label_text_reserved() is called */
1415 mutex_lock(&text_mutex);
1417 if (!kprobe_aggrprobe(orig_p)) {
1418 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1419 ap = alloc_aggr_kprobe(orig_p);
1424 init_aggr_kprobe(ap, orig_p);
1425 } else if (kprobe_unused(ap)) {
1426 /* This probe is going to die. Rescue it */
1427 ret = reuse_unused_kprobe(ap);
1432 if (kprobe_gone(ap)) {
1434 * Attempting to insert new probe at the same location that
1435 * had a probe in the module vaddr area which already
1436 * freed. So, the instruction slot has already been
1437 * released. We need a new slot for the new probe.
1439 ret = arch_prepare_kprobe(ap);
1442 * Even if fail to allocate new slot, don't need to
1443 * free aggr_probe. It will be used next time, or
1444 * freed by unregister_kprobe.
1448 /* Prepare optimized instructions if possible. */
1449 prepare_optimized_kprobe(ap);
1452 * Clear gone flag to prevent allocating new slot again, and
1453 * set disabled flag because it is not armed yet.
1455 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1456 | KPROBE_FLAG_DISABLED;
1459 /* Copy ap's insn slot to p */
1461 ret = add_new_kprobe(ap, p);
1464 mutex_unlock(&text_mutex);
1465 jump_label_unlock();
1468 if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
1469 ap->flags &= ~KPROBE_FLAG_DISABLED;
1470 if (!kprobes_all_disarmed) {
1471 /* Arm the breakpoint again. */
1472 ret = arm_kprobe(ap);
1474 ap->flags |= KPROBE_FLAG_DISABLED;
1475 list_del_rcu(&p->list);
1483 bool __weak arch_within_kprobe_blacklist(unsigned long addr)
1485 /* The __kprobes marked functions and entry code must not be probed */
1486 return addr >= (unsigned long)__kprobes_text_start &&
1487 addr < (unsigned long)__kprobes_text_end;
1490 static bool __within_kprobe_blacklist(unsigned long addr)
1492 struct kprobe_blacklist_entry *ent;
1494 if (arch_within_kprobe_blacklist(addr))
1497 * If there exists a kprobe_blacklist, verify and
1498 * fail any probe registration in the prohibited area
1500 list_for_each_entry(ent, &kprobe_blacklist, list) {
1501 if (addr >= ent->start_addr && addr < ent->end_addr)
1507 bool within_kprobe_blacklist(unsigned long addr)
1509 char symname[KSYM_NAME_LEN], *p;
1511 if (__within_kprobe_blacklist(addr))
1514 /* Check if the address is on a suffixed-symbol */
1515 if (!lookup_symbol_name(addr, symname)) {
1516 p = strchr(symname, '.');
1520 addr = (unsigned long)kprobe_lookup_name(symname, 0);
1522 return __within_kprobe_blacklist(addr);
1528 * If we have a symbol_name argument, look it up and add the offset field
1529 * to it. This way, we can specify a relative address to a symbol.
1530 * This returns encoded errors if it fails to look up symbol or invalid
1531 * combination of parameters.
1533 static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr,
1534 const char *symbol_name, unsigned int offset)
1536 if ((symbol_name && addr) || (!symbol_name && !addr))
1540 addr = kprobe_lookup_name(symbol_name, offset);
1542 return ERR_PTR(-ENOENT);
1545 addr = (kprobe_opcode_t *)(((char *)addr) + offset);
1550 return ERR_PTR(-EINVAL);
1553 static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
1555 return _kprobe_addr(p->addr, p->symbol_name, p->offset);
1558 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1559 static struct kprobe *__get_valid_kprobe(struct kprobe *p)
1561 struct kprobe *ap, *list_p;
1563 lockdep_assert_held(&kprobe_mutex);
1565 ap = get_kprobe(p->addr);
1570 list_for_each_entry(list_p, &ap->list, list)
1572 /* kprobe p is a valid probe */
1580 /* Return error if the kprobe is being re-registered */
1581 static inline int check_kprobe_rereg(struct kprobe *p)
1585 mutex_lock(&kprobe_mutex);
1586 if (__get_valid_kprobe(p))
1588 mutex_unlock(&kprobe_mutex);
1593 int __weak arch_check_ftrace_location(struct kprobe *p)
1595 unsigned long ftrace_addr;
1597 ftrace_addr = ftrace_location((unsigned long)p->addr);
1599 #ifdef CONFIG_KPROBES_ON_FTRACE
1600 /* Given address is not on the instruction boundary */
1601 if ((unsigned long)p->addr != ftrace_addr)
1603 p->flags |= KPROBE_FLAG_FTRACE;
1604 #else /* !CONFIG_KPROBES_ON_FTRACE */
1611 static int check_kprobe_address_safe(struct kprobe *p,
1612 struct module **probed_mod)
1616 ret = arch_check_ftrace_location(p);
1622 /* Ensure it is not in reserved area nor out of text */
1623 if (!kernel_text_address((unsigned long) p->addr) ||
1624 within_kprobe_blacklist((unsigned long) p->addr) ||
1625 jump_label_text_reserved(p->addr, p->addr) ||
1626 find_bug((unsigned long)p->addr)) {
1631 /* Check if are we probing a module */
1632 *probed_mod = __module_text_address((unsigned long) p->addr);
1635 * We must hold a refcount of the probed module while updating
1636 * its code to prohibit unexpected unloading.
1638 if (unlikely(!try_module_get(*probed_mod))) {
1644 * If the module freed .init.text, we couldn't insert
1647 if (within_module_init((unsigned long)p->addr, *probed_mod) &&
1648 (*probed_mod)->state != MODULE_STATE_COMING) {
1649 module_put(*probed_mod);
1656 jump_label_unlock();
1661 int register_kprobe(struct kprobe *p)
1664 struct kprobe *old_p;
1665 struct module *probed_mod;
1666 kprobe_opcode_t *addr;
1668 /* Adjust probe address from symbol */
1669 addr = kprobe_addr(p);
1671 return PTR_ERR(addr);
1674 ret = check_kprobe_rereg(p);
1678 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1679 p->flags &= KPROBE_FLAG_DISABLED;
1681 INIT_LIST_HEAD(&p->list);
1683 ret = check_kprobe_address_safe(p, &probed_mod);
1687 mutex_lock(&kprobe_mutex);
1689 old_p = get_kprobe(p->addr);
1691 /* Since this may unoptimize old_p, locking text_mutex. */
1692 ret = register_aggr_kprobe(old_p, p);
1697 /* Prevent text modification */
1698 mutex_lock(&text_mutex);
1699 ret = prepare_kprobe(p);
1700 mutex_unlock(&text_mutex);
1705 INIT_HLIST_NODE(&p->hlist);
1706 hlist_add_head_rcu(&p->hlist,
1707 &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1709 if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
1710 ret = arm_kprobe(p);
1712 hlist_del_rcu(&p->hlist);
1718 /* Try to optimize kprobe */
1719 try_to_optimize_kprobe(p);
1721 mutex_unlock(&kprobe_mutex);
1724 module_put(probed_mod);
1728 EXPORT_SYMBOL_GPL(register_kprobe);
1730 /* Check if all probes on the aggrprobe are disabled */
1731 static int aggr_kprobe_disabled(struct kprobe *ap)
1735 lockdep_assert_held(&kprobe_mutex);
1737 list_for_each_entry(kp, &ap->list, list)
1738 if (!kprobe_disabled(kp))
1740 * There is an active probe on the list.
1741 * We can't disable this ap.
1748 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1749 static struct kprobe *__disable_kprobe(struct kprobe *p)
1751 struct kprobe *orig_p;
1754 /* Get an original kprobe for return */
1755 orig_p = __get_valid_kprobe(p);
1756 if (unlikely(orig_p == NULL))
1757 return ERR_PTR(-EINVAL);
1759 if (!kprobe_disabled(p)) {
1760 /* Disable probe if it is a child probe */
1762 p->flags |= KPROBE_FLAG_DISABLED;
1764 /* Try to disarm and disable this/parent probe */
1765 if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1767 * If kprobes_all_disarmed is set, orig_p
1768 * should have already been disarmed, so
1769 * skip unneed disarming process.
1771 if (!kprobes_all_disarmed) {
1772 ret = disarm_kprobe(orig_p, true);
1774 p->flags &= ~KPROBE_FLAG_DISABLED;
1775 return ERR_PTR(ret);
1778 orig_p->flags |= KPROBE_FLAG_DISABLED;
1786 * Unregister a kprobe without a scheduler synchronization.
1788 static int __unregister_kprobe_top(struct kprobe *p)
1790 struct kprobe *ap, *list_p;
1792 /* Disable kprobe. This will disarm it if needed. */
1793 ap = __disable_kprobe(p);
1799 * This probe is an independent(and non-optimized) kprobe
1800 * (not an aggrprobe). Remove from the hash list.
1804 /* Following process expects this probe is an aggrprobe */
1805 WARN_ON(!kprobe_aggrprobe(ap));
1807 if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1809 * !disarmed could be happen if the probe is under delayed
1814 /* If disabling probe has special handlers, update aggrprobe */
1815 if (p->post_handler && !kprobe_gone(p)) {
1816 list_for_each_entry(list_p, &ap->list, list) {
1817 if ((list_p != p) && (list_p->post_handler))
1820 ap->post_handler = NULL;
1824 * Remove from the aggrprobe: this path will do nothing in
1825 * __unregister_kprobe_bottom().
1827 list_del_rcu(&p->list);
1828 if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1830 * Try to optimize this probe again, because post
1831 * handler may have been changed.
1833 optimize_kprobe(ap);
1838 hlist_del_rcu(&ap->hlist);
1842 static void __unregister_kprobe_bottom(struct kprobe *p)
1846 if (list_empty(&p->list))
1847 /* This is an independent kprobe */
1848 arch_remove_kprobe(p);
1849 else if (list_is_singular(&p->list)) {
1850 /* This is the last child of an aggrprobe */
1851 ap = list_entry(p->list.next, struct kprobe, list);
1853 free_aggr_kprobe(ap);
1855 /* Otherwise, do nothing. */
1858 int register_kprobes(struct kprobe **kps, int num)
1864 for (i = 0; i < num; i++) {
1865 ret = register_kprobe(kps[i]);
1868 unregister_kprobes(kps, i);
1874 EXPORT_SYMBOL_GPL(register_kprobes);
1876 void unregister_kprobe(struct kprobe *p)
1878 unregister_kprobes(&p, 1);
1880 EXPORT_SYMBOL_GPL(unregister_kprobe);
1882 void unregister_kprobes(struct kprobe **kps, int num)
1888 mutex_lock(&kprobe_mutex);
1889 for (i = 0; i < num; i++)
1890 if (__unregister_kprobe_top(kps[i]) < 0)
1891 kps[i]->addr = NULL;
1892 mutex_unlock(&kprobe_mutex);
1895 for (i = 0; i < num; i++)
1897 __unregister_kprobe_bottom(kps[i]);
1899 EXPORT_SYMBOL_GPL(unregister_kprobes);
1901 int __weak kprobe_exceptions_notify(struct notifier_block *self,
1902 unsigned long val, void *data)
1906 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
1908 static struct notifier_block kprobe_exceptions_nb = {
1909 .notifier_call = kprobe_exceptions_notify,
1910 .priority = 0x7fffffff /* we need to be notified first */
1913 unsigned long __weak arch_deref_entry_point(void *entry)
1915 return (unsigned long)entry;
1918 #ifdef CONFIG_KRETPROBES
1920 * This kprobe pre_handler is registered with every kretprobe. When probe
1921 * hits it will set up the return probe.
1923 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
1925 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1926 unsigned long hash, flags = 0;
1927 struct kretprobe_instance *ri;
1930 * To avoid deadlocks, prohibit return probing in NMI contexts,
1931 * just skip the probe and increase the (inexact) 'nmissed'
1932 * statistical counter, so that the user is informed that
1933 * something happened:
1935 if (unlikely(in_nmi())) {
1940 /* TODO: consider to only swap the RA after the last pre_handler fired */
1941 hash = hash_ptr(current, KPROBE_HASH_BITS);
1942 raw_spin_lock_irqsave(&rp->lock, flags);
1943 if (!hlist_empty(&rp->free_instances)) {
1944 ri = hlist_entry(rp->free_instances.first,
1945 struct kretprobe_instance, hlist);
1946 hlist_del(&ri->hlist);
1947 raw_spin_unlock_irqrestore(&rp->lock, flags);
1952 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1953 raw_spin_lock_irqsave(&rp->lock, flags);
1954 hlist_add_head(&ri->hlist, &rp->free_instances);
1955 raw_spin_unlock_irqrestore(&rp->lock, flags);
1959 arch_prepare_kretprobe(ri, regs);
1961 /* XXX(hch): why is there no hlist_move_head? */
1962 INIT_HLIST_NODE(&ri->hlist);
1963 kretprobe_table_lock(hash, &flags);
1964 hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1965 kretprobe_table_unlock(hash, &flags);
1968 raw_spin_unlock_irqrestore(&rp->lock, flags);
1972 NOKPROBE_SYMBOL(pre_handler_kretprobe);
1974 bool __weak arch_kprobe_on_func_entry(unsigned long offset)
1979 bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
1981 kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset);
1983 if (IS_ERR(kp_addr))
1986 if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) ||
1987 !arch_kprobe_on_func_entry(offset))
1993 int register_kretprobe(struct kretprobe *rp)
1996 struct kretprobe_instance *inst;
2000 if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset))
2003 if (kretprobe_blacklist_size) {
2004 addr = kprobe_addr(&rp->kp);
2006 return PTR_ERR(addr);
2008 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2009 if (kretprobe_blacklist[i].addr == addr)
2014 rp->kp.pre_handler = pre_handler_kretprobe;
2015 rp->kp.post_handler = NULL;
2016 rp->kp.fault_handler = NULL;
2018 /* Pre-allocate memory for max kretprobe instances */
2019 if (rp->maxactive <= 0) {
2020 #ifdef CONFIG_PREEMPTION
2021 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
2023 rp->maxactive = num_possible_cpus();
2026 raw_spin_lock_init(&rp->lock);
2027 INIT_HLIST_HEAD(&rp->free_instances);
2028 for (i = 0; i < rp->maxactive; i++) {
2029 inst = kmalloc(sizeof(struct kretprobe_instance) +
2030 rp->data_size, GFP_KERNEL);
2035 INIT_HLIST_NODE(&inst->hlist);
2036 hlist_add_head(&inst->hlist, &rp->free_instances);
2040 /* Establish function entry probe point */
2041 ret = register_kprobe(&rp->kp);
2046 EXPORT_SYMBOL_GPL(register_kretprobe);
2048 int register_kretprobes(struct kretprobe **rps, int num)
2054 for (i = 0; i < num; i++) {
2055 ret = register_kretprobe(rps[i]);
2058 unregister_kretprobes(rps, i);
2064 EXPORT_SYMBOL_GPL(register_kretprobes);
2066 void unregister_kretprobe(struct kretprobe *rp)
2068 unregister_kretprobes(&rp, 1);
2070 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2072 void unregister_kretprobes(struct kretprobe **rps, int num)
2078 mutex_lock(&kprobe_mutex);
2079 for (i = 0; i < num; i++)
2080 if (__unregister_kprobe_top(&rps[i]->kp) < 0)
2081 rps[i]->kp.addr = NULL;
2082 mutex_unlock(&kprobe_mutex);
2085 for (i = 0; i < num; i++) {
2086 if (rps[i]->kp.addr) {
2087 __unregister_kprobe_bottom(&rps[i]->kp);
2088 cleanup_rp_inst(rps[i]);
2092 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2094 #else /* CONFIG_KRETPROBES */
2095 int register_kretprobe(struct kretprobe *rp)
2099 EXPORT_SYMBOL_GPL(register_kretprobe);
2101 int register_kretprobes(struct kretprobe **rps, int num)
2105 EXPORT_SYMBOL_GPL(register_kretprobes);
2107 void unregister_kretprobe(struct kretprobe *rp)
2110 EXPORT_SYMBOL_GPL(unregister_kretprobe);
2112 void unregister_kretprobes(struct kretprobe **rps, int num)
2115 EXPORT_SYMBOL_GPL(unregister_kretprobes);
2117 static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2121 NOKPROBE_SYMBOL(pre_handler_kretprobe);
2123 #endif /* CONFIG_KRETPROBES */
2125 /* Set the kprobe gone and remove its instruction buffer. */
2126 static void kill_kprobe(struct kprobe *p)
2130 lockdep_assert_held(&kprobe_mutex);
2132 p->flags |= KPROBE_FLAG_GONE;
2133 if (kprobe_aggrprobe(p)) {
2135 * If this is an aggr_kprobe, we have to list all the
2136 * chained probes and mark them GONE.
2138 list_for_each_entry(kp, &p->list, list)
2139 kp->flags |= KPROBE_FLAG_GONE;
2140 p->post_handler = NULL;
2141 kill_optimized_kprobe(p);
2144 * Here, we can remove insn_slot safely, because no thread calls
2145 * the original probed function (which will be freed soon) any more.
2147 arch_remove_kprobe(p);
2150 /* Disable one kprobe */
2151 int disable_kprobe(struct kprobe *kp)
2156 mutex_lock(&kprobe_mutex);
2158 /* Disable this kprobe */
2159 p = __disable_kprobe(kp);
2163 mutex_unlock(&kprobe_mutex);
2166 EXPORT_SYMBOL_GPL(disable_kprobe);
2168 /* Enable one kprobe */
2169 int enable_kprobe(struct kprobe *kp)
2174 mutex_lock(&kprobe_mutex);
2176 /* Check whether specified probe is valid. */
2177 p = __get_valid_kprobe(kp);
2178 if (unlikely(p == NULL)) {
2183 if (kprobe_gone(kp)) {
2184 /* This kprobe has gone, we couldn't enable it. */
2190 kp->flags &= ~KPROBE_FLAG_DISABLED;
2192 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2193 p->flags &= ~KPROBE_FLAG_DISABLED;
2194 ret = arm_kprobe(p);
2196 p->flags |= KPROBE_FLAG_DISABLED;
2199 mutex_unlock(&kprobe_mutex);
2202 EXPORT_SYMBOL_GPL(enable_kprobe);
2204 /* Caller must NOT call this in usual path. This is only for critical case */
2205 void dump_kprobe(struct kprobe *kp)
2207 pr_err("Dumping kprobe:\n");
2208 pr_err("Name: %s\nOffset: %x\nAddress: %pS\n",
2209 kp->symbol_name, kp->offset, kp->addr);
2211 NOKPROBE_SYMBOL(dump_kprobe);
2213 int kprobe_add_ksym_blacklist(unsigned long entry)
2215 struct kprobe_blacklist_entry *ent;
2216 unsigned long offset = 0, size = 0;
2218 if (!kernel_text_address(entry) ||
2219 !kallsyms_lookup_size_offset(entry, &size, &offset))
2222 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
2225 ent->start_addr = entry;
2226 ent->end_addr = entry + size;
2227 INIT_LIST_HEAD(&ent->list);
2228 list_add_tail(&ent->list, &kprobe_blacklist);
2233 /* Add all symbols in given area into kprobe blacklist */
2234 int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
2236 unsigned long entry;
2239 for (entry = start; entry < end; entry += ret) {
2240 ret = kprobe_add_ksym_blacklist(entry);
2243 if (ret == 0) /* In case of alias symbol */
2249 /* Remove all symbols in given area from kprobe blacklist */
2250 static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
2252 struct kprobe_blacklist_entry *ent, *n;
2254 list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
2255 if (ent->start_addr < start || ent->start_addr >= end)
2257 list_del(&ent->list);
2262 static void kprobe_remove_ksym_blacklist(unsigned long entry)
2264 kprobe_remove_area_blacklist(entry, entry + 1);
2267 int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
2268 char *type, char *sym)
2273 int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
2276 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
2277 if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym))
2279 #ifdef CONFIG_OPTPROBES
2280 if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym))
2284 if (!arch_kprobe_get_kallsym(&symnum, value, type, sym))
2289 int __init __weak arch_populate_kprobe_blacklist(void)
2295 * Lookup and populate the kprobe_blacklist.
2297 * Unlike the kretprobe blacklist, we'll need to determine
2298 * the range of addresses that belong to the said functions,
2299 * since a kprobe need not necessarily be at the beginning
2302 static int __init populate_kprobe_blacklist(unsigned long *start,
2305 unsigned long entry;
2306 unsigned long *iter;
2309 for (iter = start; iter < end; iter++) {
2310 entry = arch_deref_entry_point((void *)*iter);
2311 ret = kprobe_add_ksym_blacklist(entry);
2318 /* Symbols in __kprobes_text are blacklisted */
2319 ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
2320 (unsigned long)__kprobes_text_end);
2324 /* Symbols in noinstr section are blacklisted */
2325 ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
2326 (unsigned long)__noinstr_text_end);
2328 return ret ? : arch_populate_kprobe_blacklist();
2331 static void add_module_kprobe_blacklist(struct module *mod)
2333 unsigned long start, end;
2336 if (mod->kprobe_blacklist) {
2337 for (i = 0; i < mod->num_kprobe_blacklist; i++)
2338 kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
2341 start = (unsigned long)mod->kprobes_text_start;
2343 end = start + mod->kprobes_text_size;
2344 kprobe_add_area_blacklist(start, end);
2347 start = (unsigned long)mod->noinstr_text_start;
2349 end = start + mod->noinstr_text_size;
2350 kprobe_add_area_blacklist(start, end);
2354 static void remove_module_kprobe_blacklist(struct module *mod)
2356 unsigned long start, end;
2359 if (mod->kprobe_blacklist) {
2360 for (i = 0; i < mod->num_kprobe_blacklist; i++)
2361 kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
2364 start = (unsigned long)mod->kprobes_text_start;
2366 end = start + mod->kprobes_text_size;
2367 kprobe_remove_area_blacklist(start, end);
2370 start = (unsigned long)mod->noinstr_text_start;
2372 end = start + mod->noinstr_text_size;
2373 kprobe_remove_area_blacklist(start, end);
2377 /* Module notifier call back, checking kprobes on the module */
2378 static int kprobes_module_callback(struct notifier_block *nb,
2379 unsigned long val, void *data)
2381 struct module *mod = data;
2382 struct hlist_head *head;
2385 int checkcore = (val == MODULE_STATE_GOING);
2387 if (val == MODULE_STATE_COMING) {
2388 mutex_lock(&kprobe_mutex);
2389 add_module_kprobe_blacklist(mod);
2390 mutex_unlock(&kprobe_mutex);
2392 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
2396 * When MODULE_STATE_GOING was notified, both of module .text and
2397 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2398 * notified, only .init.text section would be freed. We need to
2399 * disable kprobes which have been inserted in the sections.
2401 mutex_lock(&kprobe_mutex);
2402 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2403 head = &kprobe_table[i];
2404 hlist_for_each_entry(p, head, hlist)
2405 if (within_module_init((unsigned long)p->addr, mod) ||
2407 within_module_core((unsigned long)p->addr, mod))) {
2409 * The vaddr this probe is installed will soon
2410 * be vfreed buy not synced to disk. Hence,
2411 * disarming the breakpoint isn't needed.
2413 * Note, this will also move any optimized probes
2414 * that are pending to be removed from their
2415 * corresponding lists to the freeing_list and
2416 * will not be touched by the delayed
2417 * kprobe_optimizer work handler.
2422 if (val == MODULE_STATE_GOING)
2423 remove_module_kprobe_blacklist(mod);
2424 mutex_unlock(&kprobe_mutex);
2428 static struct notifier_block kprobe_module_nb = {
2429 .notifier_call = kprobes_module_callback,
2433 /* Markers of _kprobe_blacklist section */
2434 extern unsigned long __start_kprobe_blacklist[];
2435 extern unsigned long __stop_kprobe_blacklist[];
2437 static int __init init_kprobes(void)
2441 /* FIXME allocate the probe table, currently defined statically */
2442 /* initialize all list heads */
2443 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2444 INIT_HLIST_HEAD(&kprobe_table[i]);
2445 INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
2446 raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
2449 err = populate_kprobe_blacklist(__start_kprobe_blacklist,
2450 __stop_kprobe_blacklist);
2452 pr_err("kprobes: failed to populate blacklist: %d\n", err);
2453 pr_err("Please take care of using kprobes.\n");
2456 if (kretprobe_blacklist_size) {
2457 /* lookup the function address from its name */
2458 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2459 kretprobe_blacklist[i].addr =
2460 kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
2461 if (!kretprobe_blacklist[i].addr)
2462 printk("kretprobe: lookup failed: %s\n",
2463 kretprobe_blacklist[i].name);
2467 #if defined(CONFIG_OPTPROBES)
2468 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2469 /* Init kprobe_optinsn_slots */
2470 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2472 /* By default, kprobes can be optimized */
2473 kprobes_allow_optimization = true;
2476 /* By default, kprobes are armed */
2477 kprobes_all_disarmed = false;
2479 err = arch_init_kprobes();
2481 err = register_die_notifier(&kprobe_exceptions_nb);
2483 err = register_module_notifier(&kprobe_module_nb);
2485 kprobes_initialized = (err == 0);
2491 subsys_initcall(init_kprobes);
2493 #ifdef CONFIG_DEBUG_FS
2494 static void report_probe(struct seq_file *pi, struct kprobe *p,
2495 const char *sym, int offset, char *modname, struct kprobe *pp)
2498 void *addr = p->addr;
2500 if (p->pre_handler == pre_handler_kretprobe)
2505 if (!kallsyms_show_value(pi->file->f_cred))
2509 seq_printf(pi, "%px %s %s+0x%x %s ",
2510 addr, kprobe_type, sym, offset,
2511 (modname ? modname : " "));
2512 else /* try to use %pS */
2513 seq_printf(pi, "%px %s %pS ",
2514 addr, kprobe_type, p->addr);
2518 seq_printf(pi, "%s%s%s%s\n",
2519 (kprobe_gone(p) ? "[GONE]" : ""),
2520 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
2521 (kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
2522 (kprobe_ftrace(pp) ? "[FTRACE]" : ""));
2525 static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2527 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2530 static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2533 if (*pos >= KPROBE_TABLE_SIZE)
2538 static void kprobe_seq_stop(struct seq_file *f, void *v)
2543 static int show_kprobe_addr(struct seq_file *pi, void *v)
2545 struct hlist_head *head;
2546 struct kprobe *p, *kp;
2547 const char *sym = NULL;
2548 unsigned int i = *(loff_t *) v;
2549 unsigned long offset = 0;
2550 char *modname, namebuf[KSYM_NAME_LEN];
2552 head = &kprobe_table[i];
2554 hlist_for_each_entry_rcu(p, head, hlist) {
2555 sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2556 &offset, &modname, namebuf);
2557 if (kprobe_aggrprobe(p)) {
2558 list_for_each_entry_rcu(kp, &p->list, list)
2559 report_probe(pi, kp, sym, offset, modname, p);
2561 report_probe(pi, p, sym, offset, modname, NULL);
2567 static const struct seq_operations kprobes_sops = {
2568 .start = kprobe_seq_start,
2569 .next = kprobe_seq_next,
2570 .stop = kprobe_seq_stop,
2571 .show = show_kprobe_addr
2574 DEFINE_SEQ_ATTRIBUTE(kprobes);
2576 /* kprobes/blacklist -- shows which functions can not be probed */
2577 static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
2579 mutex_lock(&kprobe_mutex);
2580 return seq_list_start(&kprobe_blacklist, *pos);
2583 static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
2585 return seq_list_next(v, &kprobe_blacklist, pos);
2588 static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
2590 struct kprobe_blacklist_entry *ent =
2591 list_entry(v, struct kprobe_blacklist_entry, list);
2594 * If /proc/kallsyms is not showing kernel address, we won't
2595 * show them here either.
2597 if (!kallsyms_show_value(m->file->f_cred))
2598 seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
2599 (void *)ent->start_addr);
2601 seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
2602 (void *)ent->end_addr, (void *)ent->start_addr);
2606 static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
2608 mutex_unlock(&kprobe_mutex);
2611 static const struct seq_operations kprobe_blacklist_sops = {
2612 .start = kprobe_blacklist_seq_start,
2613 .next = kprobe_blacklist_seq_next,
2614 .stop = kprobe_blacklist_seq_stop,
2615 .show = kprobe_blacklist_seq_show,
2617 DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist);
2619 static int arm_all_kprobes(void)
2621 struct hlist_head *head;
2623 unsigned int i, total = 0, errors = 0;
2626 mutex_lock(&kprobe_mutex);
2628 /* If kprobes are armed, just return */
2629 if (!kprobes_all_disarmed)
2630 goto already_enabled;
2633 * optimize_kprobe() called by arm_kprobe() checks
2634 * kprobes_all_disarmed, so set kprobes_all_disarmed before
2637 kprobes_all_disarmed = false;
2638 /* Arming kprobes doesn't optimize kprobe itself */
2639 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2640 head = &kprobe_table[i];
2641 /* Arm all kprobes on a best-effort basis */
2642 hlist_for_each_entry(p, head, hlist) {
2643 if (!kprobe_disabled(p)) {
2644 err = arm_kprobe(p);
2655 pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n",
2658 pr_info("Kprobes globally enabled\n");
2661 mutex_unlock(&kprobe_mutex);
2665 static int disarm_all_kprobes(void)
2667 struct hlist_head *head;
2669 unsigned int i, total = 0, errors = 0;
2672 mutex_lock(&kprobe_mutex);
2674 /* If kprobes are already disarmed, just return */
2675 if (kprobes_all_disarmed) {
2676 mutex_unlock(&kprobe_mutex);
2680 kprobes_all_disarmed = true;
2682 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2683 head = &kprobe_table[i];
2684 /* Disarm all kprobes on a best-effort basis */
2685 hlist_for_each_entry(p, head, hlist) {
2686 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
2687 err = disarm_kprobe(p, false);
2698 pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n",
2701 pr_info("Kprobes globally disabled\n");
2703 mutex_unlock(&kprobe_mutex);
2705 /* Wait for disarming all kprobes by optimizer */
2706 wait_for_kprobe_optimizer();
2712 * XXX: The debugfs bool file interface doesn't allow for callbacks
2713 * when the bool state is switched. We can reuse that facility when
2716 static ssize_t read_enabled_file_bool(struct file *file,
2717 char __user *user_buf, size_t count, loff_t *ppos)
2721 if (!kprobes_all_disarmed)
2727 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2730 static ssize_t write_enabled_file_bool(struct file *file,
2731 const char __user *user_buf, size_t count, loff_t *ppos)
2737 buf_size = min(count, (sizeof(buf)-1));
2738 if (copy_from_user(buf, user_buf, buf_size))
2741 buf[buf_size] = '\0';
2746 ret = arm_all_kprobes();
2751 ret = disarm_all_kprobes();
2763 static const struct file_operations fops_kp = {
2764 .read = read_enabled_file_bool,
2765 .write = write_enabled_file_bool,
2766 .llseek = default_llseek,
2769 static int __init debugfs_kprobe_init(void)
2772 unsigned int value = 1;
2774 dir = debugfs_create_dir("kprobes", NULL);
2776 debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops);
2778 debugfs_create_file("enabled", 0600, dir, &value, &fops_kp);
2780 debugfs_create_file("blacklist", 0400, dir, NULL,
2781 &kprobe_blacklist_fops);
2786 late_initcall(debugfs_kprobe_init);
2787 #endif /* CONFIG_DEBUG_FS */