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 static inline int prepare_kprobe(struct kprobe
*p
)
1116 return arch_prepare_kprobe(p
);
1119 static inline int arm_kprobe_ftrace(struct kprobe
*p
)
1124 static inline int disarm_kprobe_ftrace(struct kprobe
*p
)
1130 /* Arm a kprobe with text_mutex */
1131 static int arm_kprobe(struct kprobe
*kp
)
1133 if (unlikely(kprobe_ftrace(kp
)))
1134 return arm_kprobe_ftrace(kp
);
1137 mutex_lock(&text_mutex
);
1139 mutex_unlock(&text_mutex
);
1145 /* Disarm a kprobe with text_mutex */
1146 static int disarm_kprobe(struct kprobe
*kp
, bool reopt
)
1148 if (unlikely(kprobe_ftrace(kp
)))
1149 return disarm_kprobe_ftrace(kp
);
1152 mutex_lock(&text_mutex
);
1153 __disarm_kprobe(kp
, reopt
);
1154 mutex_unlock(&text_mutex
);
1161 * Aggregate handlers for multiple kprobes support - these handlers
1162 * take care of invoking the individual kprobe handlers on p->list
1164 static int aggr_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1168 list_for_each_entry_rcu(kp
, &p
->list
, list
) {
1169 if (kp
->pre_handler
&& likely(!kprobe_disabled(kp
))) {
1170 set_kprobe_instance(kp
);
1171 if (kp
->pre_handler(kp
, regs
))
1174 reset_kprobe_instance();
1178 NOKPROBE_SYMBOL(aggr_pre_handler
);
1180 static void aggr_post_handler(struct kprobe
*p
, struct pt_regs
*regs
,
1181 unsigned long flags
)
1185 list_for_each_entry_rcu(kp
, &p
->list
, list
) {
1186 if (kp
->post_handler
&& likely(!kprobe_disabled(kp
))) {
1187 set_kprobe_instance(kp
);
1188 kp
->post_handler(kp
, regs
, flags
);
1189 reset_kprobe_instance();
1193 NOKPROBE_SYMBOL(aggr_post_handler
);
1195 static int aggr_fault_handler(struct kprobe
*p
, struct pt_regs
*regs
,
1198 struct kprobe
*cur
= __this_cpu_read(kprobe_instance
);
1201 * if we faulted "during" the execution of a user specified
1202 * probe handler, invoke just that probe's fault handler
1204 if (cur
&& cur
->fault_handler
) {
1205 if (cur
->fault_handler(cur
, regs
, trapnr
))
1210 NOKPROBE_SYMBOL(aggr_fault_handler
);
1212 /* Walks the list and increments nmissed count for multiprobe case */
1213 void kprobes_inc_nmissed_count(struct kprobe
*p
)
1216 if (!kprobe_aggrprobe(p
)) {
1219 list_for_each_entry_rcu(kp
, &p
->list
, list
)
1224 NOKPROBE_SYMBOL(kprobes_inc_nmissed_count
);
1226 void recycle_rp_inst(struct kretprobe_instance
*ri
,
1227 struct hlist_head
*head
)
1229 struct kretprobe
*rp
= ri
->rp
;
1231 /* remove rp inst off the rprobe_inst_table */
1232 hlist_del(&ri
->hlist
);
1233 INIT_HLIST_NODE(&ri
->hlist
);
1235 raw_spin_lock(&rp
->lock
);
1236 hlist_add_head(&ri
->hlist
, &rp
->free_instances
);
1237 raw_spin_unlock(&rp
->lock
);
1240 hlist_add_head(&ri
->hlist
, head
);
1242 NOKPROBE_SYMBOL(recycle_rp_inst
);
1244 void kretprobe_hash_lock(struct task_struct
*tsk
,
1245 struct hlist_head
**head
, unsigned long *flags
)
1246 __acquires(hlist_lock
)
1248 unsigned long hash
= hash_ptr(tsk
, KPROBE_HASH_BITS
);
1249 raw_spinlock_t
*hlist_lock
;
1251 *head
= &kretprobe_inst_table
[hash
];
1252 hlist_lock
= kretprobe_table_lock_ptr(hash
);
1253 raw_spin_lock_irqsave(hlist_lock
, *flags
);
1255 NOKPROBE_SYMBOL(kretprobe_hash_lock
);
1257 static void kretprobe_table_lock(unsigned long hash
,
1258 unsigned long *flags
)
1259 __acquires(hlist_lock
)
1261 raw_spinlock_t
*hlist_lock
= kretprobe_table_lock_ptr(hash
);
1262 raw_spin_lock_irqsave(hlist_lock
, *flags
);
1264 NOKPROBE_SYMBOL(kretprobe_table_lock
);
1266 void kretprobe_hash_unlock(struct task_struct
*tsk
,
1267 unsigned long *flags
)
1268 __releases(hlist_lock
)
1270 unsigned long hash
= hash_ptr(tsk
, KPROBE_HASH_BITS
);
1271 raw_spinlock_t
*hlist_lock
;
1273 hlist_lock
= kretprobe_table_lock_ptr(hash
);
1274 raw_spin_unlock_irqrestore(hlist_lock
, *flags
);
1276 NOKPROBE_SYMBOL(kretprobe_hash_unlock
);
1278 static void kretprobe_table_unlock(unsigned long hash
,
1279 unsigned long *flags
)
1280 __releases(hlist_lock
)
1282 raw_spinlock_t
*hlist_lock
= kretprobe_table_lock_ptr(hash
);
1283 raw_spin_unlock_irqrestore(hlist_lock
, *flags
);
1285 NOKPROBE_SYMBOL(kretprobe_table_unlock
);
1287 struct kprobe kprobe_busy
= {
1288 .addr
= (void *) get_kprobe
,
1291 void kprobe_busy_begin(void)
1293 struct kprobe_ctlblk
*kcb
;
1296 __this_cpu_write(current_kprobe
, &kprobe_busy
);
1297 kcb
= get_kprobe_ctlblk();
1298 kcb
->kprobe_status
= KPROBE_HIT_ACTIVE
;
1301 void kprobe_busy_end(void)
1303 __this_cpu_write(current_kprobe
, NULL
);
1308 * This function is called from finish_task_switch when task tk becomes dead,
1309 * so that we can recycle any function-return probe instances associated
1310 * with this task. These left over instances represent probed functions
1311 * that have been called but will never return.
1313 void kprobe_flush_task(struct task_struct
*tk
)
1315 struct kretprobe_instance
*ri
;
1316 struct hlist_head
*head
, empty_rp
;
1317 struct hlist_node
*tmp
;
1318 unsigned long hash
, flags
= 0;
1320 if (unlikely(!kprobes_initialized
))
1321 /* Early boot. kretprobe_table_locks not yet initialized. */
1324 kprobe_busy_begin();
1326 INIT_HLIST_HEAD(&empty_rp
);
1327 hash
= hash_ptr(tk
, KPROBE_HASH_BITS
);
1328 head
= &kretprobe_inst_table
[hash
];
1329 kretprobe_table_lock(hash
, &flags
);
1330 hlist_for_each_entry_safe(ri
, tmp
, head
, hlist
) {
1332 recycle_rp_inst(ri
, &empty_rp
);
1334 kretprobe_table_unlock(hash
, &flags
);
1335 hlist_for_each_entry_safe(ri
, tmp
, &empty_rp
, hlist
) {
1336 hlist_del(&ri
->hlist
);
1342 NOKPROBE_SYMBOL(kprobe_flush_task
);
1344 static inline void free_rp_inst(struct kretprobe
*rp
)
1346 struct kretprobe_instance
*ri
;
1347 struct hlist_node
*next
;
1349 hlist_for_each_entry_safe(ri
, next
, &rp
->free_instances
, hlist
) {
1350 hlist_del(&ri
->hlist
);
1355 static void cleanup_rp_inst(struct kretprobe
*rp
)
1357 unsigned long flags
, hash
;
1358 struct kretprobe_instance
*ri
;
1359 struct hlist_node
*next
;
1360 struct hlist_head
*head
;
1363 for (hash
= 0; hash
< KPROBE_TABLE_SIZE
; hash
++) {
1364 kretprobe_table_lock(hash
, &flags
);
1365 head
= &kretprobe_inst_table
[hash
];
1366 hlist_for_each_entry_safe(ri
, next
, head
, hlist
) {
1370 kretprobe_table_unlock(hash
, &flags
);
1374 NOKPROBE_SYMBOL(cleanup_rp_inst
);
1376 /* Add the new probe to ap->list */
1377 static int add_new_kprobe(struct kprobe
*ap
, struct kprobe
*p
)
1379 if (p
->post_handler
)
1380 unoptimize_kprobe(ap
, true); /* Fall back to normal kprobe */
1382 list_add_rcu(&p
->list
, &ap
->list
);
1383 if (p
->post_handler
&& !ap
->post_handler
)
1384 ap
->post_handler
= aggr_post_handler
;
1390 * Fill in the required fields of the "manager kprobe". Replace the
1391 * earlier kprobe in the hlist with the manager kprobe
1393 static void init_aggr_kprobe(struct kprobe
*ap
, struct kprobe
*p
)
1395 /* Copy p's insn slot to ap */
1397 flush_insn_slot(ap
);
1399 ap
->flags
= p
->flags
& ~KPROBE_FLAG_OPTIMIZED
;
1400 ap
->pre_handler
= aggr_pre_handler
;
1401 ap
->fault_handler
= aggr_fault_handler
;
1402 /* We don't care the kprobe which has gone. */
1403 if (p
->post_handler
&& !kprobe_gone(p
))
1404 ap
->post_handler
= aggr_post_handler
;
1406 INIT_LIST_HEAD(&ap
->list
);
1407 INIT_HLIST_NODE(&ap
->hlist
);
1409 list_add_rcu(&p
->list
, &ap
->list
);
1410 hlist_replace_rcu(&p
->hlist
, &ap
->hlist
);
1414 * This is the second or subsequent kprobe at the address - handle
1417 static int register_aggr_kprobe(struct kprobe
*orig_p
, struct kprobe
*p
)
1420 struct kprobe
*ap
= orig_p
;
1424 /* For preparing optimization, jump_label_text_reserved() is called */
1426 mutex_lock(&text_mutex
);
1428 if (!kprobe_aggrprobe(orig_p
)) {
1429 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1430 ap
= alloc_aggr_kprobe(orig_p
);
1435 init_aggr_kprobe(ap
, orig_p
);
1436 } else if (kprobe_unused(ap
)) {
1437 /* This probe is going to die. Rescue it */
1438 ret
= reuse_unused_kprobe(ap
);
1443 if (kprobe_gone(ap
)) {
1445 * Attempting to insert new probe at the same location that
1446 * had a probe in the module vaddr area which already
1447 * freed. So, the instruction slot has already been
1448 * released. We need a new slot for the new probe.
1450 ret
= arch_prepare_kprobe(ap
);
1453 * Even if fail to allocate new slot, don't need to
1454 * free aggr_probe. It will be used next time, or
1455 * freed by unregister_kprobe.
1459 /* Prepare optimized instructions if possible. */
1460 prepare_optimized_kprobe(ap
);
1463 * Clear gone flag to prevent allocating new slot again, and
1464 * set disabled flag because it is not armed yet.
1466 ap
->flags
= (ap
->flags
& ~KPROBE_FLAG_GONE
)
1467 | KPROBE_FLAG_DISABLED
;
1470 /* Copy ap's insn slot to p */
1472 ret
= add_new_kprobe(ap
, p
);
1475 mutex_unlock(&text_mutex
);
1476 jump_label_unlock();
1479 if (ret
== 0 && kprobe_disabled(ap
) && !kprobe_disabled(p
)) {
1480 ap
->flags
&= ~KPROBE_FLAG_DISABLED
;
1481 if (!kprobes_all_disarmed
) {
1482 /* Arm the breakpoint again. */
1483 ret
= arm_kprobe(ap
);
1485 ap
->flags
|= KPROBE_FLAG_DISABLED
;
1486 list_del_rcu(&p
->list
);
1494 bool __weak
arch_within_kprobe_blacklist(unsigned long addr
)
1496 /* The __kprobes marked functions and entry code must not be probed */
1497 return addr
>= (unsigned long)__kprobes_text_start
&&
1498 addr
< (unsigned long)__kprobes_text_end
;
1501 static bool __within_kprobe_blacklist(unsigned long addr
)
1503 struct kprobe_blacklist_entry
*ent
;
1505 if (arch_within_kprobe_blacklist(addr
))
1508 * If there exists a kprobe_blacklist, verify and
1509 * fail any probe registration in the prohibited area
1511 list_for_each_entry(ent
, &kprobe_blacklist
, list
) {
1512 if (addr
>= ent
->start_addr
&& addr
< ent
->end_addr
)
1518 bool within_kprobe_blacklist(unsigned long addr
)
1520 char symname
[KSYM_NAME_LEN
], *p
;
1522 if (__within_kprobe_blacklist(addr
))
1525 /* Check if the address is on a suffixed-symbol */
1526 if (!lookup_symbol_name(addr
, symname
)) {
1527 p
= strchr(symname
, '.');
1531 addr
= (unsigned long)kprobe_lookup_name(symname
, 0);
1533 return __within_kprobe_blacklist(addr
);
1539 * If we have a symbol_name argument, look it up and add the offset field
1540 * to it. This way, we can specify a relative address to a symbol.
1541 * This returns encoded errors if it fails to look up symbol or invalid
1542 * combination of parameters.
1544 static kprobe_opcode_t
*_kprobe_addr(kprobe_opcode_t
*addr
,
1545 const char *symbol_name
, unsigned int offset
)
1547 if ((symbol_name
&& addr
) || (!symbol_name
&& !addr
))
1551 addr
= kprobe_lookup_name(symbol_name
, offset
);
1553 return ERR_PTR(-ENOENT
);
1556 addr
= (kprobe_opcode_t
*)(((char *)addr
) + offset
);
1561 return ERR_PTR(-EINVAL
);
1564 static kprobe_opcode_t
*kprobe_addr(struct kprobe
*p
)
1566 return _kprobe_addr(p
->addr
, p
->symbol_name
, p
->offset
);
1569 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1570 static struct kprobe
*__get_valid_kprobe(struct kprobe
*p
)
1572 struct kprobe
*ap
, *list_p
;
1574 lockdep_assert_held(&kprobe_mutex
);
1576 ap
= get_kprobe(p
->addr
);
1581 list_for_each_entry(list_p
, &ap
->list
, list
)
1583 /* kprobe p is a valid probe */
1591 /* Return error if the kprobe is being re-registered */
1592 static inline int check_kprobe_rereg(struct kprobe
*p
)
1596 mutex_lock(&kprobe_mutex
);
1597 if (__get_valid_kprobe(p
))
1599 mutex_unlock(&kprobe_mutex
);
1604 int __weak
arch_check_ftrace_location(struct kprobe
*p
)
1606 unsigned long ftrace_addr
;
1608 ftrace_addr
= ftrace_location((unsigned long)p
->addr
);
1610 #ifdef CONFIG_KPROBES_ON_FTRACE
1611 /* Given address is not on the instruction boundary */
1612 if ((unsigned long)p
->addr
!= ftrace_addr
)
1614 p
->flags
|= KPROBE_FLAG_FTRACE
;
1615 #else /* !CONFIG_KPROBES_ON_FTRACE */
1622 static int check_kprobe_address_safe(struct kprobe
*p
,
1623 struct module
**probed_mod
)
1627 ret
= arch_check_ftrace_location(p
);
1633 /* Ensure it is not in reserved area nor out of text */
1634 if (!kernel_text_address((unsigned long) p
->addr
) ||
1635 within_kprobe_blacklist((unsigned long) p
->addr
) ||
1636 jump_label_text_reserved(p
->addr
, p
->addr
) ||
1637 find_bug((unsigned long)p
->addr
)) {
1642 /* Check if are we probing a module */
1643 *probed_mod
= __module_text_address((unsigned long) p
->addr
);
1646 * We must hold a refcount of the probed module while updating
1647 * its code to prohibit unexpected unloading.
1649 if (unlikely(!try_module_get(*probed_mod
))) {
1655 * If the module freed .init.text, we couldn't insert
1658 if (within_module_init((unsigned long)p
->addr
, *probed_mod
) &&
1659 (*probed_mod
)->state
!= MODULE_STATE_COMING
) {
1660 module_put(*probed_mod
);
1667 jump_label_unlock();
1672 int register_kprobe(struct kprobe
*p
)
1675 struct kprobe
*old_p
;
1676 struct module
*probed_mod
;
1677 kprobe_opcode_t
*addr
;
1679 /* Adjust probe address from symbol */
1680 addr
= kprobe_addr(p
);
1682 return PTR_ERR(addr
);
1685 ret
= check_kprobe_rereg(p
);
1689 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1690 p
->flags
&= KPROBE_FLAG_DISABLED
;
1692 INIT_LIST_HEAD(&p
->list
);
1694 ret
= check_kprobe_address_safe(p
, &probed_mod
);
1698 mutex_lock(&kprobe_mutex
);
1700 old_p
= get_kprobe(p
->addr
);
1702 /* Since this may unoptimize old_p, locking text_mutex. */
1703 ret
= register_aggr_kprobe(old_p
, p
);
1708 /* Prevent text modification */
1709 mutex_lock(&text_mutex
);
1710 ret
= prepare_kprobe(p
);
1711 mutex_unlock(&text_mutex
);
1716 INIT_HLIST_NODE(&p
->hlist
);
1717 hlist_add_head_rcu(&p
->hlist
,
1718 &kprobe_table
[hash_ptr(p
->addr
, KPROBE_HASH_BITS
)]);
1720 if (!kprobes_all_disarmed
&& !kprobe_disabled(p
)) {
1721 ret
= arm_kprobe(p
);
1723 hlist_del_rcu(&p
->hlist
);
1729 /* Try to optimize kprobe */
1730 try_to_optimize_kprobe(p
);
1732 mutex_unlock(&kprobe_mutex
);
1735 module_put(probed_mod
);
1739 EXPORT_SYMBOL_GPL(register_kprobe
);
1741 /* Check if all probes on the aggrprobe are disabled */
1742 static int aggr_kprobe_disabled(struct kprobe
*ap
)
1746 lockdep_assert_held(&kprobe_mutex
);
1748 list_for_each_entry(kp
, &ap
->list
, list
)
1749 if (!kprobe_disabled(kp
))
1751 * There is an active probe on the list.
1752 * We can't disable this ap.
1759 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1760 static struct kprobe
*__disable_kprobe(struct kprobe
*p
)
1762 struct kprobe
*orig_p
;
1765 /* Get an original kprobe for return */
1766 orig_p
= __get_valid_kprobe(p
);
1767 if (unlikely(orig_p
== NULL
))
1768 return ERR_PTR(-EINVAL
);
1770 if (!kprobe_disabled(p
)) {
1771 /* Disable probe if it is a child probe */
1773 p
->flags
|= KPROBE_FLAG_DISABLED
;
1775 /* Try to disarm and disable this/parent probe */
1776 if (p
== orig_p
|| aggr_kprobe_disabled(orig_p
)) {
1778 * If kprobes_all_disarmed is set, orig_p
1779 * should have already been disarmed, so
1780 * skip unneed disarming process.
1782 if (!kprobes_all_disarmed
) {
1783 ret
= disarm_kprobe(orig_p
, true);
1785 p
->flags
&= ~KPROBE_FLAG_DISABLED
;
1786 return ERR_PTR(ret
);
1789 orig_p
->flags
|= KPROBE_FLAG_DISABLED
;
1797 * Unregister a kprobe without a scheduler synchronization.
1799 static int __unregister_kprobe_top(struct kprobe
*p
)
1801 struct kprobe
*ap
, *list_p
;
1803 /* Disable kprobe. This will disarm it if needed. */
1804 ap
= __disable_kprobe(p
);
1810 * This probe is an independent(and non-optimized) kprobe
1811 * (not an aggrprobe). Remove from the hash list.
1815 /* Following process expects this probe is an aggrprobe */
1816 WARN_ON(!kprobe_aggrprobe(ap
));
1818 if (list_is_singular(&ap
->list
) && kprobe_disarmed(ap
))
1820 * !disarmed could be happen if the probe is under delayed
1825 /* If disabling probe has special handlers, update aggrprobe */
1826 if (p
->post_handler
&& !kprobe_gone(p
)) {
1827 list_for_each_entry(list_p
, &ap
->list
, list
) {
1828 if ((list_p
!= p
) && (list_p
->post_handler
))
1831 ap
->post_handler
= NULL
;
1835 * Remove from the aggrprobe: this path will do nothing in
1836 * __unregister_kprobe_bottom().
1838 list_del_rcu(&p
->list
);
1839 if (!kprobe_disabled(ap
) && !kprobes_all_disarmed
)
1841 * Try to optimize this probe again, because post
1842 * handler may have been changed.
1844 optimize_kprobe(ap
);
1849 hlist_del_rcu(&ap
->hlist
);
1853 static void __unregister_kprobe_bottom(struct kprobe
*p
)
1857 if (list_empty(&p
->list
))
1858 /* This is an independent kprobe */
1859 arch_remove_kprobe(p
);
1860 else if (list_is_singular(&p
->list
)) {
1861 /* This is the last child of an aggrprobe */
1862 ap
= list_entry(p
->list
.next
, struct kprobe
, list
);
1864 free_aggr_kprobe(ap
);
1866 /* Otherwise, do nothing. */
1869 int register_kprobes(struct kprobe
**kps
, int num
)
1875 for (i
= 0; i
< num
; i
++) {
1876 ret
= register_kprobe(kps
[i
]);
1879 unregister_kprobes(kps
, i
);
1885 EXPORT_SYMBOL_GPL(register_kprobes
);
1887 void unregister_kprobe(struct kprobe
*p
)
1889 unregister_kprobes(&p
, 1);
1891 EXPORT_SYMBOL_GPL(unregister_kprobe
);
1893 void unregister_kprobes(struct kprobe
**kps
, int num
)
1899 mutex_lock(&kprobe_mutex
);
1900 for (i
= 0; i
< num
; i
++)
1901 if (__unregister_kprobe_top(kps
[i
]) < 0)
1902 kps
[i
]->addr
= NULL
;
1903 mutex_unlock(&kprobe_mutex
);
1906 for (i
= 0; i
< num
; i
++)
1908 __unregister_kprobe_bottom(kps
[i
]);
1910 EXPORT_SYMBOL_GPL(unregister_kprobes
);
1912 int __weak
kprobe_exceptions_notify(struct notifier_block
*self
,
1913 unsigned long val
, void *data
)
1917 NOKPROBE_SYMBOL(kprobe_exceptions_notify
);
1919 static struct notifier_block kprobe_exceptions_nb
= {
1920 .notifier_call
= kprobe_exceptions_notify
,
1921 .priority
= 0x7fffffff /* we need to be notified first */
1924 unsigned long __weak
arch_deref_entry_point(void *entry
)
1926 return (unsigned long)entry
;
1929 #ifdef CONFIG_KRETPROBES
1931 * This kprobe pre_handler is registered with every kretprobe. When probe
1932 * hits it will set up the return probe.
1934 static int pre_handler_kretprobe(struct kprobe
*p
, struct pt_regs
*regs
)
1936 struct kretprobe
*rp
= container_of(p
, struct kretprobe
, kp
);
1937 unsigned long hash
, flags
= 0;
1938 struct kretprobe_instance
*ri
;
1941 * To avoid deadlocks, prohibit return probing in NMI contexts,
1942 * just skip the probe and increase the (inexact) 'nmissed'
1943 * statistical counter, so that the user is informed that
1944 * something happened:
1946 if (unlikely(in_nmi())) {
1951 /* TODO: consider to only swap the RA after the last pre_handler fired */
1952 hash
= hash_ptr(current
, KPROBE_HASH_BITS
);
1953 raw_spin_lock_irqsave(&rp
->lock
, flags
);
1954 if (!hlist_empty(&rp
->free_instances
)) {
1955 ri
= hlist_entry(rp
->free_instances
.first
,
1956 struct kretprobe_instance
, hlist
);
1957 hlist_del(&ri
->hlist
);
1958 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1963 if (rp
->entry_handler
&& rp
->entry_handler(ri
, regs
)) {
1964 raw_spin_lock_irqsave(&rp
->lock
, flags
);
1965 hlist_add_head(&ri
->hlist
, &rp
->free_instances
);
1966 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1970 arch_prepare_kretprobe(ri
, regs
);
1972 /* XXX(hch): why is there no hlist_move_head? */
1973 INIT_HLIST_NODE(&ri
->hlist
);
1974 kretprobe_table_lock(hash
, &flags
);
1975 hlist_add_head(&ri
->hlist
, &kretprobe_inst_table
[hash
]);
1976 kretprobe_table_unlock(hash
, &flags
);
1979 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1983 NOKPROBE_SYMBOL(pre_handler_kretprobe
);
1985 bool __weak
arch_kprobe_on_func_entry(unsigned long offset
)
1990 bool kprobe_on_func_entry(kprobe_opcode_t
*addr
, const char *sym
, unsigned long offset
)
1992 kprobe_opcode_t
*kp_addr
= _kprobe_addr(addr
, sym
, offset
);
1994 if (IS_ERR(kp_addr
))
1997 if (!kallsyms_lookup_size_offset((unsigned long)kp_addr
, NULL
, &offset
) ||
1998 !arch_kprobe_on_func_entry(offset
))
2004 int register_kretprobe(struct kretprobe
*rp
)
2007 struct kretprobe_instance
*inst
;
2011 if (!kprobe_on_func_entry(rp
->kp
.addr
, rp
->kp
.symbol_name
, rp
->kp
.offset
))
2014 if (kretprobe_blacklist_size
) {
2015 addr
= kprobe_addr(&rp
->kp
);
2017 return PTR_ERR(addr
);
2019 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
2020 if (kretprobe_blacklist
[i
].addr
== addr
)
2025 rp
->kp
.pre_handler
= pre_handler_kretprobe
;
2026 rp
->kp
.post_handler
= NULL
;
2027 rp
->kp
.fault_handler
= NULL
;
2029 /* Pre-allocate memory for max kretprobe instances */
2030 if (rp
->maxactive
<= 0) {
2031 #ifdef CONFIG_PREEMPTION
2032 rp
->maxactive
= max_t(unsigned int, 10, 2*num_possible_cpus());
2034 rp
->maxactive
= num_possible_cpus();
2037 raw_spin_lock_init(&rp
->lock
);
2038 INIT_HLIST_HEAD(&rp
->free_instances
);
2039 for (i
= 0; i
< rp
->maxactive
; i
++) {
2040 inst
= kmalloc(sizeof(struct kretprobe_instance
) +
2041 rp
->data_size
, GFP_KERNEL
);
2046 INIT_HLIST_NODE(&inst
->hlist
);
2047 hlist_add_head(&inst
->hlist
, &rp
->free_instances
);
2051 /* Establish function entry probe point */
2052 ret
= register_kprobe(&rp
->kp
);
2057 EXPORT_SYMBOL_GPL(register_kretprobe
);
2059 int register_kretprobes(struct kretprobe
**rps
, int num
)
2065 for (i
= 0; i
< num
; i
++) {
2066 ret
= register_kretprobe(rps
[i
]);
2069 unregister_kretprobes(rps
, i
);
2075 EXPORT_SYMBOL_GPL(register_kretprobes
);
2077 void unregister_kretprobe(struct kretprobe
*rp
)
2079 unregister_kretprobes(&rp
, 1);
2081 EXPORT_SYMBOL_GPL(unregister_kretprobe
);
2083 void unregister_kretprobes(struct kretprobe
**rps
, int num
)
2089 mutex_lock(&kprobe_mutex
);
2090 for (i
= 0; i
< num
; i
++)
2091 if (__unregister_kprobe_top(&rps
[i
]->kp
) < 0)
2092 rps
[i
]->kp
.addr
= NULL
;
2093 mutex_unlock(&kprobe_mutex
);
2096 for (i
= 0; i
< num
; i
++) {
2097 if (rps
[i
]->kp
.addr
) {
2098 __unregister_kprobe_bottom(&rps
[i
]->kp
);
2099 cleanup_rp_inst(rps
[i
]);
2103 EXPORT_SYMBOL_GPL(unregister_kretprobes
);
2105 #else /* CONFIG_KRETPROBES */
2106 int register_kretprobe(struct kretprobe
*rp
)
2110 EXPORT_SYMBOL_GPL(register_kretprobe
);
2112 int register_kretprobes(struct kretprobe
**rps
, int num
)
2116 EXPORT_SYMBOL_GPL(register_kretprobes
);
2118 void unregister_kretprobe(struct kretprobe
*rp
)
2121 EXPORT_SYMBOL_GPL(unregister_kretprobe
);
2123 void unregister_kretprobes(struct kretprobe
**rps
, int num
)
2126 EXPORT_SYMBOL_GPL(unregister_kretprobes
);
2128 static int pre_handler_kretprobe(struct kprobe
*p
, struct pt_regs
*regs
)
2132 NOKPROBE_SYMBOL(pre_handler_kretprobe
);
2134 #endif /* CONFIG_KRETPROBES */
2136 /* Set the kprobe gone and remove its instruction buffer. */
2137 static void kill_kprobe(struct kprobe
*p
)
2141 lockdep_assert_held(&kprobe_mutex
);
2143 p
->flags
|= KPROBE_FLAG_GONE
;
2144 if (kprobe_aggrprobe(p
)) {
2146 * If this is an aggr_kprobe, we have to list all the
2147 * chained probes and mark them GONE.
2149 list_for_each_entry(kp
, &p
->list
, list
)
2150 kp
->flags
|= KPROBE_FLAG_GONE
;
2151 p
->post_handler
= NULL
;
2152 kill_optimized_kprobe(p
);
2155 * Here, we can remove insn_slot safely, because no thread calls
2156 * the original probed function (which will be freed soon) any more.
2158 arch_remove_kprobe(p
);
2161 * The module is going away. We should disarm the kprobe which
2164 if (kprobe_ftrace(p
))
2165 disarm_kprobe_ftrace(p
);
2168 /* Disable one kprobe */
2169 int disable_kprobe(struct kprobe
*kp
)
2174 mutex_lock(&kprobe_mutex
);
2176 /* Disable this kprobe */
2177 p
= __disable_kprobe(kp
);
2181 mutex_unlock(&kprobe_mutex
);
2184 EXPORT_SYMBOL_GPL(disable_kprobe
);
2186 /* Enable one kprobe */
2187 int enable_kprobe(struct kprobe
*kp
)
2192 mutex_lock(&kprobe_mutex
);
2194 /* Check whether specified probe is valid. */
2195 p
= __get_valid_kprobe(kp
);
2196 if (unlikely(p
== NULL
)) {
2201 if (kprobe_gone(kp
)) {
2202 /* This kprobe has gone, we couldn't enable it. */
2208 kp
->flags
&= ~KPROBE_FLAG_DISABLED
;
2210 if (!kprobes_all_disarmed
&& kprobe_disabled(p
)) {
2211 p
->flags
&= ~KPROBE_FLAG_DISABLED
;
2212 ret
= arm_kprobe(p
);
2214 p
->flags
|= KPROBE_FLAG_DISABLED
;
2217 mutex_unlock(&kprobe_mutex
);
2220 EXPORT_SYMBOL_GPL(enable_kprobe
);
2222 /* Caller must NOT call this in usual path. This is only for critical case */
2223 void dump_kprobe(struct kprobe
*kp
)
2225 pr_err("Dumping kprobe:\n");
2226 pr_err("Name: %s\nOffset: %x\nAddress: %pS\n",
2227 kp
->symbol_name
, kp
->offset
, kp
->addr
);
2229 NOKPROBE_SYMBOL(dump_kprobe
);
2231 int kprobe_add_ksym_blacklist(unsigned long entry
)
2233 struct kprobe_blacklist_entry
*ent
;
2234 unsigned long offset
= 0, size
= 0;
2236 if (!kernel_text_address(entry
) ||
2237 !kallsyms_lookup_size_offset(entry
, &size
, &offset
))
2240 ent
= kmalloc(sizeof(*ent
), GFP_KERNEL
);
2243 ent
->start_addr
= entry
;
2244 ent
->end_addr
= entry
+ size
;
2245 INIT_LIST_HEAD(&ent
->list
);
2246 list_add_tail(&ent
->list
, &kprobe_blacklist
);
2251 /* Add all symbols in given area into kprobe blacklist */
2252 int kprobe_add_area_blacklist(unsigned long start
, unsigned long end
)
2254 unsigned long entry
;
2257 for (entry
= start
; entry
< end
; entry
+= ret
) {
2258 ret
= kprobe_add_ksym_blacklist(entry
);
2261 if (ret
== 0) /* In case of alias symbol */
2267 /* Remove all symbols in given area from kprobe blacklist */
2268 static void kprobe_remove_area_blacklist(unsigned long start
, unsigned long end
)
2270 struct kprobe_blacklist_entry
*ent
, *n
;
2272 list_for_each_entry_safe(ent
, n
, &kprobe_blacklist
, list
) {
2273 if (ent
->start_addr
< start
|| ent
->start_addr
>= end
)
2275 list_del(&ent
->list
);
2280 static void kprobe_remove_ksym_blacklist(unsigned long entry
)
2282 kprobe_remove_area_blacklist(entry
, entry
+ 1);
2285 int __weak
arch_kprobe_get_kallsym(unsigned int *symnum
, unsigned long *value
,
2286 char *type
, char *sym
)
2291 int kprobe_get_kallsym(unsigned int symnum
, unsigned long *value
, char *type
,
2294 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
2295 if (!kprobe_cache_get_kallsym(&kprobe_insn_slots
, &symnum
, value
, type
, sym
))
2297 #ifdef CONFIG_OPTPROBES
2298 if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots
, &symnum
, value
, type
, sym
))
2302 if (!arch_kprobe_get_kallsym(&symnum
, value
, type
, sym
))
2307 int __init __weak
arch_populate_kprobe_blacklist(void)
2313 * Lookup and populate the kprobe_blacklist.
2315 * Unlike the kretprobe blacklist, we'll need to determine
2316 * the range of addresses that belong to the said functions,
2317 * since a kprobe need not necessarily be at the beginning
2320 static int __init
populate_kprobe_blacklist(unsigned long *start
,
2323 unsigned long entry
;
2324 unsigned long *iter
;
2327 for (iter
= start
; iter
< end
; iter
++) {
2328 entry
= arch_deref_entry_point((void *)*iter
);
2329 ret
= kprobe_add_ksym_blacklist(entry
);
2336 /* Symbols in __kprobes_text are blacklisted */
2337 ret
= kprobe_add_area_blacklist((unsigned long)__kprobes_text_start
,
2338 (unsigned long)__kprobes_text_end
);
2342 /* Symbols in noinstr section are blacklisted */
2343 ret
= kprobe_add_area_blacklist((unsigned long)__noinstr_text_start
,
2344 (unsigned long)__noinstr_text_end
);
2346 return ret
? : arch_populate_kprobe_blacklist();
2349 static void add_module_kprobe_blacklist(struct module
*mod
)
2351 unsigned long start
, end
;
2354 if (mod
->kprobe_blacklist
) {
2355 for (i
= 0; i
< mod
->num_kprobe_blacklist
; i
++)
2356 kprobe_add_ksym_blacklist(mod
->kprobe_blacklist
[i
]);
2359 start
= (unsigned long)mod
->kprobes_text_start
;
2361 end
= start
+ mod
->kprobes_text_size
;
2362 kprobe_add_area_blacklist(start
, end
);
2365 start
= (unsigned long)mod
->noinstr_text_start
;
2367 end
= start
+ mod
->noinstr_text_size
;
2368 kprobe_add_area_blacklist(start
, end
);
2372 static void remove_module_kprobe_blacklist(struct module
*mod
)
2374 unsigned long start
, end
;
2377 if (mod
->kprobe_blacklist
) {
2378 for (i
= 0; i
< mod
->num_kprobe_blacklist
; i
++)
2379 kprobe_remove_ksym_blacklist(mod
->kprobe_blacklist
[i
]);
2382 start
= (unsigned long)mod
->kprobes_text_start
;
2384 end
= start
+ mod
->kprobes_text_size
;
2385 kprobe_remove_area_blacklist(start
, end
);
2388 start
= (unsigned long)mod
->noinstr_text_start
;
2390 end
= start
+ mod
->noinstr_text_size
;
2391 kprobe_remove_area_blacklist(start
, end
);
2395 /* Module notifier call back, checking kprobes on the module */
2396 static int kprobes_module_callback(struct notifier_block
*nb
,
2397 unsigned long val
, void *data
)
2399 struct module
*mod
= data
;
2400 struct hlist_head
*head
;
2403 int checkcore
= (val
== MODULE_STATE_GOING
);
2405 if (val
== MODULE_STATE_COMING
) {
2406 mutex_lock(&kprobe_mutex
);
2407 add_module_kprobe_blacklist(mod
);
2408 mutex_unlock(&kprobe_mutex
);
2410 if (val
!= MODULE_STATE_GOING
&& val
!= MODULE_STATE_LIVE
)
2414 * When MODULE_STATE_GOING was notified, both of module .text and
2415 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2416 * notified, only .init.text section would be freed. We need to
2417 * disable kprobes which have been inserted in the sections.
2419 mutex_lock(&kprobe_mutex
);
2420 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2421 head
= &kprobe_table
[i
];
2422 hlist_for_each_entry(p
, head
, hlist
)
2423 if (within_module_init((unsigned long)p
->addr
, mod
) ||
2425 within_module_core((unsigned long)p
->addr
, mod
))) {
2427 * The vaddr this probe is installed will soon
2428 * be vfreed buy not synced to disk. Hence,
2429 * disarming the breakpoint isn't needed.
2431 * Note, this will also move any optimized probes
2432 * that are pending to be removed from their
2433 * corresponding lists to the freeing_list and
2434 * will not be touched by the delayed
2435 * kprobe_optimizer work handler.
2440 if (val
== MODULE_STATE_GOING
)
2441 remove_module_kprobe_blacklist(mod
);
2442 mutex_unlock(&kprobe_mutex
);
2446 static struct notifier_block kprobe_module_nb
= {
2447 .notifier_call
= kprobes_module_callback
,
2451 /* Markers of _kprobe_blacklist section */
2452 extern unsigned long __start_kprobe_blacklist
[];
2453 extern unsigned long __stop_kprobe_blacklist
[];
2455 static int __init
init_kprobes(void)
2459 /* FIXME allocate the probe table, currently defined statically */
2460 /* initialize all list heads */
2461 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2462 INIT_HLIST_HEAD(&kprobe_table
[i
]);
2463 INIT_HLIST_HEAD(&kretprobe_inst_table
[i
]);
2464 raw_spin_lock_init(&(kretprobe_table_locks
[i
].lock
));
2467 err
= populate_kprobe_blacklist(__start_kprobe_blacklist
,
2468 __stop_kprobe_blacklist
);
2470 pr_err("kprobes: failed to populate blacklist: %d\n", err
);
2471 pr_err("Please take care of using kprobes.\n");
2474 if (kretprobe_blacklist_size
) {
2475 /* lookup the function address from its name */
2476 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
2477 kretprobe_blacklist
[i
].addr
=
2478 kprobe_lookup_name(kretprobe_blacklist
[i
].name
, 0);
2479 if (!kretprobe_blacklist
[i
].addr
)
2480 printk("kretprobe: lookup failed: %s\n",
2481 kretprobe_blacklist
[i
].name
);
2485 #if defined(CONFIG_OPTPROBES)
2486 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2487 /* Init kprobe_optinsn_slots */
2488 kprobe_optinsn_slots
.insn_size
= MAX_OPTINSN_SIZE
;
2490 /* By default, kprobes can be optimized */
2491 kprobes_allow_optimization
= true;
2494 /* By default, kprobes are armed */
2495 kprobes_all_disarmed
= false;
2497 err
= arch_init_kprobes();
2499 err
= register_die_notifier(&kprobe_exceptions_nb
);
2501 err
= register_module_notifier(&kprobe_module_nb
);
2503 kprobes_initialized
= (err
== 0);
2509 subsys_initcall(init_kprobes
);
2511 #ifdef CONFIG_DEBUG_FS
2512 static void report_probe(struct seq_file
*pi
, struct kprobe
*p
,
2513 const char *sym
, int offset
, char *modname
, struct kprobe
*pp
)
2516 void *addr
= p
->addr
;
2518 if (p
->pre_handler
== pre_handler_kretprobe
)
2523 if (!kallsyms_show_value(pi
->file
->f_cred
))
2527 seq_printf(pi
, "%px %s %s+0x%x %s ",
2528 addr
, kprobe_type
, sym
, offset
,
2529 (modname
? modname
: " "));
2530 else /* try to use %pS */
2531 seq_printf(pi
, "%px %s %pS ",
2532 addr
, kprobe_type
, p
->addr
);
2536 seq_printf(pi
, "%s%s%s%s\n",
2537 (kprobe_gone(p
) ? "[GONE]" : ""),
2538 ((kprobe_disabled(p
) && !kprobe_gone(p
)) ? "[DISABLED]" : ""),
2539 (kprobe_optimized(pp
) ? "[OPTIMIZED]" : ""),
2540 (kprobe_ftrace(pp
) ? "[FTRACE]" : ""));
2543 static void *kprobe_seq_start(struct seq_file
*f
, loff_t
*pos
)
2545 return (*pos
< KPROBE_TABLE_SIZE
) ? pos
: NULL
;
2548 static void *kprobe_seq_next(struct seq_file
*f
, void *v
, loff_t
*pos
)
2551 if (*pos
>= KPROBE_TABLE_SIZE
)
2556 static void kprobe_seq_stop(struct seq_file
*f
, void *v
)
2561 static int show_kprobe_addr(struct seq_file
*pi
, void *v
)
2563 struct hlist_head
*head
;
2564 struct kprobe
*p
, *kp
;
2565 const char *sym
= NULL
;
2566 unsigned int i
= *(loff_t
*) v
;
2567 unsigned long offset
= 0;
2568 char *modname
, namebuf
[KSYM_NAME_LEN
];
2570 head
= &kprobe_table
[i
];
2572 hlist_for_each_entry_rcu(p
, head
, hlist
) {
2573 sym
= kallsyms_lookup((unsigned long)p
->addr
, NULL
,
2574 &offset
, &modname
, namebuf
);
2575 if (kprobe_aggrprobe(p
)) {
2576 list_for_each_entry_rcu(kp
, &p
->list
, list
)
2577 report_probe(pi
, kp
, sym
, offset
, modname
, p
);
2579 report_probe(pi
, p
, sym
, offset
, modname
, NULL
);
2585 static const struct seq_operations kprobes_sops
= {
2586 .start
= kprobe_seq_start
,
2587 .next
= kprobe_seq_next
,
2588 .stop
= kprobe_seq_stop
,
2589 .show
= show_kprobe_addr
2592 DEFINE_SEQ_ATTRIBUTE(kprobes
);
2594 /* kprobes/blacklist -- shows which functions can not be probed */
2595 static void *kprobe_blacklist_seq_start(struct seq_file
*m
, loff_t
*pos
)
2597 mutex_lock(&kprobe_mutex
);
2598 return seq_list_start(&kprobe_blacklist
, *pos
);
2601 static void *kprobe_blacklist_seq_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2603 return seq_list_next(v
, &kprobe_blacklist
, pos
);
2606 static int kprobe_blacklist_seq_show(struct seq_file
*m
, void *v
)
2608 struct kprobe_blacklist_entry
*ent
=
2609 list_entry(v
, struct kprobe_blacklist_entry
, list
);
2612 * If /proc/kallsyms is not showing kernel address, we won't
2613 * show them here either.
2615 if (!kallsyms_show_value(m
->file
->f_cred
))
2616 seq_printf(m
, "0x%px-0x%px\t%ps\n", NULL
, NULL
,
2617 (void *)ent
->start_addr
);
2619 seq_printf(m
, "0x%px-0x%px\t%ps\n", (void *)ent
->start_addr
,
2620 (void *)ent
->end_addr
, (void *)ent
->start_addr
);
2624 static void kprobe_blacklist_seq_stop(struct seq_file
*f
, void *v
)
2626 mutex_unlock(&kprobe_mutex
);
2629 static const struct seq_operations kprobe_blacklist_sops
= {
2630 .start
= kprobe_blacklist_seq_start
,
2631 .next
= kprobe_blacklist_seq_next
,
2632 .stop
= kprobe_blacklist_seq_stop
,
2633 .show
= kprobe_blacklist_seq_show
,
2635 DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist
);
2637 static int arm_all_kprobes(void)
2639 struct hlist_head
*head
;
2641 unsigned int i
, total
= 0, errors
= 0;
2644 mutex_lock(&kprobe_mutex
);
2646 /* If kprobes are armed, just return */
2647 if (!kprobes_all_disarmed
)
2648 goto already_enabled
;
2651 * optimize_kprobe() called by arm_kprobe() checks
2652 * kprobes_all_disarmed, so set kprobes_all_disarmed before
2655 kprobes_all_disarmed
= false;
2656 /* Arming kprobes doesn't optimize kprobe itself */
2657 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2658 head
= &kprobe_table
[i
];
2659 /* Arm all kprobes on a best-effort basis */
2660 hlist_for_each_entry(p
, head
, hlist
) {
2661 if (!kprobe_disabled(p
)) {
2662 err
= arm_kprobe(p
);
2673 pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n",
2676 pr_info("Kprobes globally enabled\n");
2679 mutex_unlock(&kprobe_mutex
);
2683 static int disarm_all_kprobes(void)
2685 struct hlist_head
*head
;
2687 unsigned int i
, total
= 0, errors
= 0;
2690 mutex_lock(&kprobe_mutex
);
2692 /* If kprobes are already disarmed, just return */
2693 if (kprobes_all_disarmed
) {
2694 mutex_unlock(&kprobe_mutex
);
2698 kprobes_all_disarmed
= true;
2700 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2701 head
= &kprobe_table
[i
];
2702 /* Disarm all kprobes on a best-effort basis */
2703 hlist_for_each_entry(p
, head
, hlist
) {
2704 if (!arch_trampoline_kprobe(p
) && !kprobe_disabled(p
)) {
2705 err
= disarm_kprobe(p
, false);
2716 pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n",
2719 pr_info("Kprobes globally disabled\n");
2721 mutex_unlock(&kprobe_mutex
);
2723 /* Wait for disarming all kprobes by optimizer */
2724 wait_for_kprobe_optimizer();
2730 * XXX: The debugfs bool file interface doesn't allow for callbacks
2731 * when the bool state is switched. We can reuse that facility when
2734 static ssize_t
read_enabled_file_bool(struct file
*file
,
2735 char __user
*user_buf
, size_t count
, loff_t
*ppos
)
2739 if (!kprobes_all_disarmed
)
2745 return simple_read_from_buffer(user_buf
, count
, ppos
, buf
, 2);
2748 static ssize_t
write_enabled_file_bool(struct file
*file
,
2749 const char __user
*user_buf
, size_t count
, loff_t
*ppos
)
2755 buf_size
= min(count
, (sizeof(buf
)-1));
2756 if (copy_from_user(buf
, user_buf
, buf_size
))
2759 buf
[buf_size
] = '\0';
2764 ret
= arm_all_kprobes();
2769 ret
= disarm_all_kprobes();
2781 static const struct file_operations fops_kp
= {
2782 .read
= read_enabled_file_bool
,
2783 .write
= write_enabled_file_bool
,
2784 .llseek
= default_llseek
,
2787 static int __init
debugfs_kprobe_init(void)
2790 unsigned int value
= 1;
2792 dir
= debugfs_create_dir("kprobes", NULL
);
2794 debugfs_create_file("list", 0400, dir
, NULL
, &kprobes_fops
);
2796 debugfs_create_file("enabled", 0600, dir
, &value
, &fops_kp
);
2798 debugfs_create_file("blacklist", 0400, dir
, NULL
,
2799 &kprobe_blacklist_fops
);
2804 late_initcall(debugfs_kprobe_init
);
2805 #endif /* CONFIG_DEBUG_FS */