2 * Kernel Probes (KProbes)
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Copyright (C) IBM Corporation, 2002, 2004
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation (includes suggestions from
24 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
25 * hlists and exceptions notifier as suggested by Andi Kleen.
26 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
27 * interface to access function arguments.
28 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
29 * exceptions notifier to be first on the priority list.
30 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
31 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
32 * <prasanna@in.ibm.com> added function-return probes.
34 #include <linux/kprobes.h>
35 #include <linux/hash.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/stddef.h>
39 #include <linux/export.h>
40 #include <linux/moduleloader.h>
41 #include <linux/kallsyms.h>
42 #include <linux/freezer.h>
43 #include <linux/seq_file.h>
44 #include <linux/debugfs.h>
45 #include <linux/sysctl.h>
46 #include <linux/kdebug.h>
47 #include <linux/memory.h>
48 #include <linux/ftrace.h>
49 #include <linux/cpu.h>
50 #include <linux/jump_label.h>
52 #include <asm/sections.h>
53 #include <asm/cacheflush.h>
54 #include <asm/errno.h>
55 #include <linux/uaccess.h>
57 #define KPROBE_HASH_BITS 6
58 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
62 * Some oddball architectures like 64bit powerpc have function descriptors
63 * so this must be overridable.
65 #ifndef kprobe_lookup_name
66 #define kprobe_lookup_name(name, addr) \
67 addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
70 static int kprobes_initialized
;
71 static struct hlist_head kprobe_table
[KPROBE_TABLE_SIZE
];
72 static struct hlist_head kretprobe_inst_table
[KPROBE_TABLE_SIZE
];
74 /* NOTE: change this value only with kprobe_mutex held */
75 static bool kprobes_all_disarmed
;
77 /* This protects kprobe_table and optimizing_list */
78 static DEFINE_MUTEX(kprobe_mutex
);
79 static DEFINE_PER_CPU(struct kprobe
*, kprobe_instance
) = NULL
;
81 raw_spinlock_t lock ____cacheline_aligned_in_smp
;
82 } kretprobe_table_locks
[KPROBE_TABLE_SIZE
];
84 static raw_spinlock_t
*kretprobe_table_lock_ptr(unsigned long hash
)
86 return &(kretprobe_table_locks
[hash
].lock
);
89 /* Blacklist -- list of struct kprobe_blacklist_entry */
90 static LIST_HEAD(kprobe_blacklist
);
92 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
94 * kprobe->ainsn.insn points to the copy of the instruction to be
95 * single-stepped. x86_64, POWER4 and above have no-exec support and
96 * stepping on the instruction on a vmalloced/kmalloced/data page
97 * is a recipe for disaster
99 struct kprobe_insn_page
{
100 struct list_head list
;
101 kprobe_opcode_t
*insns
; /* Page of instruction slots */
102 struct kprobe_insn_cache
*cache
;
108 #define KPROBE_INSN_PAGE_SIZE(slots) \
109 (offsetof(struct kprobe_insn_page, slot_used) + \
110 (sizeof(char) * (slots)))
112 static int slots_per_page(struct kprobe_insn_cache
*c
)
114 return PAGE_SIZE
/(c
->insn_size
* sizeof(kprobe_opcode_t
));
117 enum kprobe_slot_state
{
123 static void *alloc_insn_page(void)
125 return module_alloc(PAGE_SIZE
);
128 static void free_insn_page(void *page
)
130 module_memfree(page
);
133 struct kprobe_insn_cache kprobe_insn_slots
= {
134 .mutex
= __MUTEX_INITIALIZER(kprobe_insn_slots
.mutex
),
135 .alloc
= alloc_insn_page
,
136 .free
= free_insn_page
,
137 .pages
= LIST_HEAD_INIT(kprobe_insn_slots
.pages
),
138 .insn_size
= MAX_INSN_SIZE
,
141 static int collect_garbage_slots(struct kprobe_insn_cache
*c
);
144 * __get_insn_slot() - Find a slot on an executable page for an instruction.
145 * We allocate an executable page if there's no room on existing ones.
147 kprobe_opcode_t
*__get_insn_slot(struct kprobe_insn_cache
*c
)
149 struct kprobe_insn_page
*kip
;
150 kprobe_opcode_t
*slot
= NULL
;
152 /* Since the slot array is not protected by rcu, we need a mutex */
153 mutex_lock(&c
->mutex
);
156 list_for_each_entry_rcu(kip
, &c
->pages
, list
) {
157 if (kip
->nused
< slots_per_page(c
)) {
159 for (i
= 0; i
< slots_per_page(c
); i
++) {
160 if (kip
->slot_used
[i
] == SLOT_CLEAN
) {
161 kip
->slot_used
[i
] = SLOT_USED
;
163 slot
= kip
->insns
+ (i
* c
->insn_size
);
168 /* kip->nused is broken. Fix it. */
169 kip
->nused
= slots_per_page(c
);
175 /* If there are any garbage slots, collect it and try again. */
176 if (c
->nr_garbage
&& collect_garbage_slots(c
) == 0)
179 /* All out of space. Need to allocate a new page. */
180 kip
= kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c
)), GFP_KERNEL
);
185 * Use module_alloc so this page is within +/- 2GB of where the
186 * kernel image and loaded module images reside. This is required
187 * so x86_64 can correctly handle the %rip-relative fixups.
189 kip
->insns
= c
->alloc();
194 INIT_LIST_HEAD(&kip
->list
);
195 memset(kip
->slot_used
, SLOT_CLEAN
, slots_per_page(c
));
196 kip
->slot_used
[0] = SLOT_USED
;
200 list_add_rcu(&kip
->list
, &c
->pages
);
203 mutex_unlock(&c
->mutex
);
207 /* Return 1 if all garbages are collected, otherwise 0. */
208 static int collect_one_slot(struct kprobe_insn_page
*kip
, int idx
)
210 kip
->slot_used
[idx
] = SLOT_CLEAN
;
212 if (kip
->nused
== 0) {
214 * Page is no longer in use. Free it unless
215 * it's the last one. We keep the last one
216 * so as not to have to set it up again the
217 * next time somebody inserts a probe.
219 if (!list_is_singular(&kip
->list
)) {
220 list_del_rcu(&kip
->list
);
222 kip
->cache
->free(kip
->insns
);
230 static int collect_garbage_slots(struct kprobe_insn_cache
*c
)
232 struct kprobe_insn_page
*kip
, *next
;
234 /* Ensure no-one is interrupted on the garbages */
237 list_for_each_entry_safe(kip
, next
, &c
->pages
, list
) {
239 if (kip
->ngarbage
== 0)
241 kip
->ngarbage
= 0; /* we will collect all garbages */
242 for (i
= 0; i
< slots_per_page(c
); i
++) {
243 if (kip
->slot_used
[i
] == SLOT_DIRTY
&& collect_one_slot(kip
, i
))
251 void __free_insn_slot(struct kprobe_insn_cache
*c
,
252 kprobe_opcode_t
*slot
, int dirty
)
254 struct kprobe_insn_page
*kip
;
257 mutex_lock(&c
->mutex
);
259 list_for_each_entry_rcu(kip
, &c
->pages
, list
) {
260 idx
= ((long)slot
- (long)kip
->insns
) /
261 (c
->insn_size
* sizeof(kprobe_opcode_t
));
262 if (idx
>= 0 && idx
< slots_per_page(c
))
265 /* Could not find this slot. */
270 /* Mark and sweep: this may sleep */
272 /* Check double free */
273 WARN_ON(kip
->slot_used
[idx
] != SLOT_USED
);
275 kip
->slot_used
[idx
] = SLOT_DIRTY
;
277 if (++c
->nr_garbage
> slots_per_page(c
))
278 collect_garbage_slots(c
);
280 collect_one_slot(kip
, idx
);
283 mutex_unlock(&c
->mutex
);
287 * Check given address is on the page of kprobe instruction slots.
288 * This will be used for checking whether the address on a stack
289 * is on a text area or not.
291 bool __is_insn_slot_addr(struct kprobe_insn_cache
*c
, unsigned long addr
)
293 struct kprobe_insn_page
*kip
;
297 list_for_each_entry_rcu(kip
, &c
->pages
, list
) {
298 if (addr
>= (unsigned long)kip
->insns
&&
299 addr
< (unsigned long)kip
->insns
+ PAGE_SIZE
) {
309 #ifdef CONFIG_OPTPROBES
310 /* For optimized_kprobe buffer */
311 struct kprobe_insn_cache kprobe_optinsn_slots
= {
312 .mutex
= __MUTEX_INITIALIZER(kprobe_optinsn_slots
.mutex
),
313 .alloc
= alloc_insn_page
,
314 .free
= free_insn_page
,
315 .pages
= LIST_HEAD_INIT(kprobe_optinsn_slots
.pages
),
316 /* .insn_size is initialized later */
322 /* We have preemption disabled.. so it is safe to use __ versions */
323 static inline void set_kprobe_instance(struct kprobe
*kp
)
325 __this_cpu_write(kprobe_instance
, kp
);
328 static inline void reset_kprobe_instance(void)
330 __this_cpu_write(kprobe_instance
, NULL
);
334 * This routine is called either:
335 * - under the kprobe_mutex - during kprobe_[un]register()
337 * - with preemption disabled - from arch/xxx/kernel/kprobes.c
339 struct kprobe
*get_kprobe(void *addr
)
341 struct hlist_head
*head
;
344 head
= &kprobe_table
[hash_ptr(addr
, KPROBE_HASH_BITS
)];
345 hlist_for_each_entry_rcu(p
, head
, hlist
) {
352 NOKPROBE_SYMBOL(get_kprobe
);
354 static int aggr_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
);
356 /* Return true if the kprobe is an aggregator */
357 static inline int kprobe_aggrprobe(struct kprobe
*p
)
359 return p
->pre_handler
== aggr_pre_handler
;
362 /* Return true(!0) if the kprobe is unused */
363 static inline int kprobe_unused(struct kprobe
*p
)
365 return kprobe_aggrprobe(p
) && kprobe_disabled(p
) &&
366 list_empty(&p
->list
);
370 * Keep all fields in the kprobe consistent
372 static inline void copy_kprobe(struct kprobe
*ap
, struct kprobe
*p
)
374 memcpy(&p
->opcode
, &ap
->opcode
, sizeof(kprobe_opcode_t
));
375 memcpy(&p
->ainsn
, &ap
->ainsn
, sizeof(struct arch_specific_insn
));
378 #ifdef CONFIG_OPTPROBES
379 /* NOTE: change this value only with kprobe_mutex held */
380 static bool kprobes_allow_optimization
;
383 * Call all pre_handler on the list, but ignores its return value.
384 * This must be called from arch-dep optimized caller.
386 void opt_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
390 list_for_each_entry_rcu(kp
, &p
->list
, list
) {
391 if (kp
->pre_handler
&& likely(!kprobe_disabled(kp
))) {
392 set_kprobe_instance(kp
);
393 kp
->pre_handler(kp
, regs
);
395 reset_kprobe_instance();
398 NOKPROBE_SYMBOL(opt_pre_handler
);
400 /* Free optimized instructions and optimized_kprobe */
401 static void free_aggr_kprobe(struct kprobe
*p
)
403 struct optimized_kprobe
*op
;
405 op
= container_of(p
, struct optimized_kprobe
, kp
);
406 arch_remove_optimized_kprobe(op
);
407 arch_remove_kprobe(p
);
411 /* Return true(!0) if the kprobe is ready for optimization. */
412 static inline int kprobe_optready(struct kprobe
*p
)
414 struct optimized_kprobe
*op
;
416 if (kprobe_aggrprobe(p
)) {
417 op
= container_of(p
, struct optimized_kprobe
, kp
);
418 return arch_prepared_optinsn(&op
->optinsn
);
424 /* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
425 static inline int kprobe_disarmed(struct kprobe
*p
)
427 struct optimized_kprobe
*op
;
429 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
430 if (!kprobe_aggrprobe(p
))
431 return kprobe_disabled(p
);
433 op
= container_of(p
, struct optimized_kprobe
, kp
);
435 return kprobe_disabled(p
) && list_empty(&op
->list
);
438 /* Return true(!0) if the probe is queued on (un)optimizing lists */
439 static int kprobe_queued(struct kprobe
*p
)
441 struct optimized_kprobe
*op
;
443 if (kprobe_aggrprobe(p
)) {
444 op
= container_of(p
, struct optimized_kprobe
, kp
);
445 if (!list_empty(&op
->list
))
452 * Return an optimized kprobe whose optimizing code replaces
453 * instructions including addr (exclude breakpoint).
455 static struct kprobe
*get_optimized_kprobe(unsigned long addr
)
458 struct kprobe
*p
= NULL
;
459 struct optimized_kprobe
*op
;
461 /* Don't check i == 0, since that is a breakpoint case. */
462 for (i
= 1; !p
&& i
< MAX_OPTIMIZED_LENGTH
; i
++)
463 p
= get_kprobe((void *)(addr
- i
));
465 if (p
&& kprobe_optready(p
)) {
466 op
= container_of(p
, struct optimized_kprobe
, kp
);
467 if (arch_within_optimized_kprobe(op
, addr
))
474 /* Optimization staging list, protected by kprobe_mutex */
475 static LIST_HEAD(optimizing_list
);
476 static LIST_HEAD(unoptimizing_list
);
477 static LIST_HEAD(freeing_list
);
479 static void kprobe_optimizer(struct work_struct
*work
);
480 static DECLARE_DELAYED_WORK(optimizing_work
, kprobe_optimizer
);
481 #define OPTIMIZE_DELAY 5
484 * Optimize (replace a breakpoint with a jump) kprobes listed on
487 static void do_optimize_kprobes(void)
489 /* Optimization never be done when disarmed */
490 if (kprobes_all_disarmed
|| !kprobes_allow_optimization
||
491 list_empty(&optimizing_list
))
495 * The optimization/unoptimization refers online_cpus via
496 * stop_machine() and cpu-hotplug modifies online_cpus.
497 * And same time, text_mutex will be held in cpu-hotplug and here.
498 * This combination can cause a deadlock (cpu-hotplug try to lock
499 * text_mutex but stop_machine can not be done because online_cpus
501 * To avoid this deadlock, we need to call get_online_cpus()
502 * for preventing cpu-hotplug outside of text_mutex locking.
505 mutex_lock(&text_mutex
);
506 arch_optimize_kprobes(&optimizing_list
);
507 mutex_unlock(&text_mutex
);
512 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
513 * if need) kprobes listed on unoptimizing_list.
515 static void do_unoptimize_kprobes(void)
517 struct optimized_kprobe
*op
, *tmp
;
519 /* Unoptimization must be done anytime */
520 if (list_empty(&unoptimizing_list
))
523 /* Ditto to do_optimize_kprobes */
525 mutex_lock(&text_mutex
);
526 arch_unoptimize_kprobes(&unoptimizing_list
, &freeing_list
);
527 /* Loop free_list for disarming */
528 list_for_each_entry_safe(op
, tmp
, &freeing_list
, list
) {
529 /* Disarm probes if marked disabled */
530 if (kprobe_disabled(&op
->kp
))
531 arch_disarm_kprobe(&op
->kp
);
532 if (kprobe_unused(&op
->kp
)) {
534 * Remove unused probes from hash list. After waiting
535 * for synchronization, these probes are reclaimed.
536 * (reclaiming is done by do_free_cleaned_kprobes.)
538 hlist_del_rcu(&op
->kp
.hlist
);
540 list_del_init(&op
->list
);
542 mutex_unlock(&text_mutex
);
546 /* Reclaim all kprobes on the free_list */
547 static void do_free_cleaned_kprobes(void)
549 struct optimized_kprobe
*op
, *tmp
;
551 list_for_each_entry_safe(op
, tmp
, &freeing_list
, list
) {
552 BUG_ON(!kprobe_unused(&op
->kp
));
553 list_del_init(&op
->list
);
554 free_aggr_kprobe(&op
->kp
);
558 /* Start optimizer after OPTIMIZE_DELAY passed */
559 static void kick_kprobe_optimizer(void)
561 schedule_delayed_work(&optimizing_work
, OPTIMIZE_DELAY
);
564 /* Kprobe jump optimizer */
565 static void kprobe_optimizer(struct work_struct
*work
)
567 mutex_lock(&kprobe_mutex
);
568 /* Lock modules while optimizing kprobes */
569 mutex_lock(&module_mutex
);
572 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
573 * kprobes before waiting for quiesence period.
575 do_unoptimize_kprobes();
578 * Step 2: Wait for quiesence period to ensure all running interrupts
579 * are done. Because optprobe may modify multiple instructions
580 * there is a chance that Nth instruction is interrupted. In that
581 * case, running interrupt can return to 2nd-Nth byte of jump
582 * instruction. This wait is for avoiding it.
586 /* Step 3: Optimize kprobes after quiesence period */
587 do_optimize_kprobes();
589 /* Step 4: Free cleaned kprobes after quiesence period */
590 do_free_cleaned_kprobes();
592 mutex_unlock(&module_mutex
);
593 mutex_unlock(&kprobe_mutex
);
595 /* Step 5: Kick optimizer again if needed */
596 if (!list_empty(&optimizing_list
) || !list_empty(&unoptimizing_list
))
597 kick_kprobe_optimizer();
600 /* Wait for completing optimization and unoptimization */
601 static void wait_for_kprobe_optimizer(void)
603 mutex_lock(&kprobe_mutex
);
605 while (!list_empty(&optimizing_list
) || !list_empty(&unoptimizing_list
)) {
606 mutex_unlock(&kprobe_mutex
);
608 /* this will also make optimizing_work execute immmediately */
609 flush_delayed_work(&optimizing_work
);
610 /* @optimizing_work might not have been queued yet, relax */
613 mutex_lock(&kprobe_mutex
);
616 mutex_unlock(&kprobe_mutex
);
619 /* Optimize kprobe if p is ready to be optimized */
620 static void optimize_kprobe(struct kprobe
*p
)
622 struct optimized_kprobe
*op
;
624 /* Check if the kprobe is disabled or not ready for optimization. */
625 if (!kprobe_optready(p
) || !kprobes_allow_optimization
||
626 (kprobe_disabled(p
) || kprobes_all_disarmed
))
629 /* Both of break_handler and post_handler are not supported. */
630 if (p
->break_handler
|| p
->post_handler
)
633 op
= container_of(p
, struct optimized_kprobe
, kp
);
635 /* Check there is no other kprobes at the optimized instructions */
636 if (arch_check_optimized_kprobe(op
) < 0)
639 /* Check if it is already optimized. */
640 if (op
->kp
.flags
& KPROBE_FLAG_OPTIMIZED
)
642 op
->kp
.flags
|= KPROBE_FLAG_OPTIMIZED
;
644 if (!list_empty(&op
->list
))
645 /* This is under unoptimizing. Just dequeue the probe */
646 list_del_init(&op
->list
);
648 list_add(&op
->list
, &optimizing_list
);
649 kick_kprobe_optimizer();
653 /* Short cut to direct unoptimizing */
654 static void force_unoptimize_kprobe(struct optimized_kprobe
*op
)
657 arch_unoptimize_kprobe(op
);
659 if (kprobe_disabled(&op
->kp
))
660 arch_disarm_kprobe(&op
->kp
);
663 /* Unoptimize a kprobe if p is optimized */
664 static void unoptimize_kprobe(struct kprobe
*p
, bool force
)
666 struct optimized_kprobe
*op
;
668 if (!kprobe_aggrprobe(p
) || kprobe_disarmed(p
))
669 return; /* This is not an optprobe nor optimized */
671 op
= container_of(p
, struct optimized_kprobe
, kp
);
672 if (!kprobe_optimized(p
)) {
673 /* Unoptimized or unoptimizing case */
674 if (force
&& !list_empty(&op
->list
)) {
676 * Only if this is unoptimizing kprobe and forced,
677 * forcibly unoptimize it. (No need to unoptimize
678 * unoptimized kprobe again :)
680 list_del_init(&op
->list
);
681 force_unoptimize_kprobe(op
);
686 op
->kp
.flags
&= ~KPROBE_FLAG_OPTIMIZED
;
687 if (!list_empty(&op
->list
)) {
688 /* Dequeue from the optimization queue */
689 list_del_init(&op
->list
);
692 /* Optimized kprobe case */
694 /* Forcibly update the code: this is a special case */
695 force_unoptimize_kprobe(op
);
697 list_add(&op
->list
, &unoptimizing_list
);
698 kick_kprobe_optimizer();
702 /* Cancel unoptimizing for reusing */
703 static void reuse_unused_kprobe(struct kprobe
*ap
)
705 struct optimized_kprobe
*op
;
707 BUG_ON(!kprobe_unused(ap
));
709 * Unused kprobe MUST be on the way of delayed unoptimizing (means
710 * there is still a relative jump) and disabled.
712 op
= container_of(ap
, struct optimized_kprobe
, kp
);
713 if (unlikely(list_empty(&op
->list
)))
714 printk(KERN_WARNING
"Warning: found a stray unused "
715 "aggrprobe@%p\n", ap
->addr
);
716 /* Enable the probe again */
717 ap
->flags
&= ~KPROBE_FLAG_DISABLED
;
718 /* Optimize it again (remove from op->list) */
719 BUG_ON(!kprobe_optready(ap
));
723 /* Remove optimized instructions */
724 static void kill_optimized_kprobe(struct kprobe
*p
)
726 struct optimized_kprobe
*op
;
728 op
= container_of(p
, struct optimized_kprobe
, kp
);
729 if (!list_empty(&op
->list
))
730 /* Dequeue from the (un)optimization queue */
731 list_del_init(&op
->list
);
732 op
->kp
.flags
&= ~KPROBE_FLAG_OPTIMIZED
;
734 if (kprobe_unused(p
)) {
735 /* Enqueue if it is unused */
736 list_add(&op
->list
, &freeing_list
);
738 * Remove unused probes from the hash list. After waiting
739 * for synchronization, this probe is reclaimed.
740 * (reclaiming is done by do_free_cleaned_kprobes().)
742 hlist_del_rcu(&op
->kp
.hlist
);
745 /* Don't touch the code, because it is already freed. */
746 arch_remove_optimized_kprobe(op
);
749 /* Try to prepare optimized instructions */
750 static void prepare_optimized_kprobe(struct kprobe
*p
)
752 struct optimized_kprobe
*op
;
754 op
= container_of(p
, struct optimized_kprobe
, kp
);
755 arch_prepare_optimized_kprobe(op
, p
);
758 /* Allocate new optimized_kprobe and try to prepare optimized instructions */
759 static struct kprobe
*alloc_aggr_kprobe(struct kprobe
*p
)
761 struct optimized_kprobe
*op
;
763 op
= kzalloc(sizeof(struct optimized_kprobe
), GFP_KERNEL
);
767 INIT_LIST_HEAD(&op
->list
);
768 op
->kp
.addr
= p
->addr
;
769 arch_prepare_optimized_kprobe(op
, p
);
774 static void init_aggr_kprobe(struct kprobe
*ap
, struct kprobe
*p
);
777 * Prepare an optimized_kprobe and optimize it
778 * NOTE: p must be a normal registered kprobe
780 static void try_to_optimize_kprobe(struct kprobe
*p
)
783 struct optimized_kprobe
*op
;
785 /* Impossible to optimize ftrace-based kprobe */
786 if (kprobe_ftrace(p
))
789 /* For preparing optimization, jump_label_text_reserved() is called */
791 mutex_lock(&text_mutex
);
793 ap
= alloc_aggr_kprobe(p
);
797 op
= container_of(ap
, struct optimized_kprobe
, kp
);
798 if (!arch_prepared_optinsn(&op
->optinsn
)) {
799 /* If failed to setup optimizing, fallback to kprobe */
800 arch_remove_optimized_kprobe(op
);
805 init_aggr_kprobe(ap
, p
);
806 optimize_kprobe(ap
); /* This just kicks optimizer thread */
809 mutex_unlock(&text_mutex
);
814 static void optimize_all_kprobes(void)
816 struct hlist_head
*head
;
820 mutex_lock(&kprobe_mutex
);
821 /* If optimization is already allowed, just return */
822 if (kprobes_allow_optimization
)
825 kprobes_allow_optimization
= true;
826 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
827 head
= &kprobe_table
[i
];
828 hlist_for_each_entry_rcu(p
, head
, hlist
)
829 if (!kprobe_disabled(p
))
832 printk(KERN_INFO
"Kprobes globally optimized\n");
834 mutex_unlock(&kprobe_mutex
);
837 static void unoptimize_all_kprobes(void)
839 struct hlist_head
*head
;
843 mutex_lock(&kprobe_mutex
);
844 /* If optimization is already prohibited, just return */
845 if (!kprobes_allow_optimization
) {
846 mutex_unlock(&kprobe_mutex
);
850 kprobes_allow_optimization
= false;
851 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
852 head
= &kprobe_table
[i
];
853 hlist_for_each_entry_rcu(p
, head
, hlist
) {
854 if (!kprobe_disabled(p
))
855 unoptimize_kprobe(p
, false);
858 mutex_unlock(&kprobe_mutex
);
860 /* Wait for unoptimizing completion */
861 wait_for_kprobe_optimizer();
862 printk(KERN_INFO
"Kprobes globally unoptimized\n");
865 static DEFINE_MUTEX(kprobe_sysctl_mutex
);
866 int sysctl_kprobes_optimization
;
867 int proc_kprobes_optimization_handler(struct ctl_table
*table
, int write
,
868 void __user
*buffer
, size_t *length
,
873 mutex_lock(&kprobe_sysctl_mutex
);
874 sysctl_kprobes_optimization
= kprobes_allow_optimization
? 1 : 0;
875 ret
= proc_dointvec_minmax(table
, write
, buffer
, length
, ppos
);
877 if (sysctl_kprobes_optimization
)
878 optimize_all_kprobes();
880 unoptimize_all_kprobes();
881 mutex_unlock(&kprobe_sysctl_mutex
);
885 #endif /* CONFIG_SYSCTL */
887 /* Put a breakpoint for a probe. Must be called with text_mutex locked */
888 static void __arm_kprobe(struct kprobe
*p
)
892 /* Check collision with other optimized kprobes */
893 _p
= get_optimized_kprobe((unsigned long)p
->addr
);
895 /* Fallback to unoptimized kprobe */
896 unoptimize_kprobe(_p
, true);
899 optimize_kprobe(p
); /* Try to optimize (add kprobe to a list) */
902 /* Remove the breakpoint of a probe. Must be called with text_mutex locked */
903 static void __disarm_kprobe(struct kprobe
*p
, bool reopt
)
907 /* Try to unoptimize */
908 unoptimize_kprobe(p
, kprobes_all_disarmed
);
910 if (!kprobe_queued(p
)) {
911 arch_disarm_kprobe(p
);
912 /* If another kprobe was blocked, optimize it. */
913 _p
= get_optimized_kprobe((unsigned long)p
->addr
);
914 if (unlikely(_p
) && reopt
)
917 /* TODO: reoptimize others after unoptimized this probe */
920 #else /* !CONFIG_OPTPROBES */
922 #define optimize_kprobe(p) do {} while (0)
923 #define unoptimize_kprobe(p, f) do {} while (0)
924 #define kill_optimized_kprobe(p) do {} while (0)
925 #define prepare_optimized_kprobe(p) do {} while (0)
926 #define try_to_optimize_kprobe(p) do {} while (0)
927 #define __arm_kprobe(p) arch_arm_kprobe(p)
928 #define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
929 #define kprobe_disarmed(p) kprobe_disabled(p)
930 #define wait_for_kprobe_optimizer() do {} while (0)
932 /* There should be no unused kprobes can be reused without optimization */
933 static void reuse_unused_kprobe(struct kprobe
*ap
)
935 printk(KERN_ERR
"Error: There should be no unused kprobe here.\n");
936 BUG_ON(kprobe_unused(ap
));
939 static void free_aggr_kprobe(struct kprobe
*p
)
941 arch_remove_kprobe(p
);
945 static struct kprobe
*alloc_aggr_kprobe(struct kprobe
*p
)
947 return kzalloc(sizeof(struct kprobe
), GFP_KERNEL
);
949 #endif /* CONFIG_OPTPROBES */
951 #ifdef CONFIG_KPROBES_ON_FTRACE
952 static struct ftrace_ops kprobe_ftrace_ops __read_mostly
= {
953 .func
= kprobe_ftrace_handler
,
954 .flags
= FTRACE_OPS_FL_SAVE_REGS
| FTRACE_OPS_FL_IPMODIFY
,
956 static int kprobe_ftrace_enabled
;
958 /* Must ensure p->addr is really on ftrace */
959 static int prepare_kprobe(struct kprobe
*p
)
961 if (!kprobe_ftrace(p
))
962 return arch_prepare_kprobe(p
);
964 return arch_prepare_kprobe_ftrace(p
);
967 /* Caller must lock kprobe_mutex */
968 static void arm_kprobe_ftrace(struct kprobe
*p
)
972 ret
= ftrace_set_filter_ip(&kprobe_ftrace_ops
,
973 (unsigned long)p
->addr
, 0, 0);
974 WARN(ret
< 0, "Failed to arm kprobe-ftrace at %p (%d)\n", p
->addr
, ret
);
975 kprobe_ftrace_enabled
++;
976 if (kprobe_ftrace_enabled
== 1) {
977 ret
= register_ftrace_function(&kprobe_ftrace_ops
);
978 WARN(ret
< 0, "Failed to init kprobe-ftrace (%d)\n", ret
);
982 /* Caller must lock kprobe_mutex */
983 static void disarm_kprobe_ftrace(struct kprobe
*p
)
987 kprobe_ftrace_enabled
--;
988 if (kprobe_ftrace_enabled
== 0) {
989 ret
= unregister_ftrace_function(&kprobe_ftrace_ops
);
990 WARN(ret
< 0, "Failed to init kprobe-ftrace (%d)\n", ret
);
992 ret
= ftrace_set_filter_ip(&kprobe_ftrace_ops
,
993 (unsigned long)p
->addr
, 1, 0);
994 WARN(ret
< 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p
->addr
, ret
);
996 #else /* !CONFIG_KPROBES_ON_FTRACE */
997 #define prepare_kprobe(p) arch_prepare_kprobe(p)
998 #define arm_kprobe_ftrace(p) do {} while (0)
999 #define disarm_kprobe_ftrace(p) do {} while (0)
1002 /* Arm a kprobe with text_mutex */
1003 static void arm_kprobe(struct kprobe
*kp
)
1005 if (unlikely(kprobe_ftrace(kp
))) {
1006 arm_kprobe_ftrace(kp
);
1010 * Here, since __arm_kprobe() doesn't use stop_machine(),
1011 * this doesn't cause deadlock on text_mutex. So, we don't
1012 * need get_online_cpus().
1014 mutex_lock(&text_mutex
);
1016 mutex_unlock(&text_mutex
);
1019 /* Disarm a kprobe with text_mutex */
1020 static void disarm_kprobe(struct kprobe
*kp
, bool reopt
)
1022 if (unlikely(kprobe_ftrace(kp
))) {
1023 disarm_kprobe_ftrace(kp
);
1027 mutex_lock(&text_mutex
);
1028 __disarm_kprobe(kp
, reopt
);
1029 mutex_unlock(&text_mutex
);
1033 * Aggregate handlers for multiple kprobes support - these handlers
1034 * take care of invoking the individual kprobe handlers on p->list
1036 static int aggr_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1040 list_for_each_entry_rcu(kp
, &p
->list
, list
) {
1041 if (kp
->pre_handler
&& likely(!kprobe_disabled(kp
))) {
1042 set_kprobe_instance(kp
);
1043 if (kp
->pre_handler(kp
, regs
))
1046 reset_kprobe_instance();
1050 NOKPROBE_SYMBOL(aggr_pre_handler
);
1052 static void aggr_post_handler(struct kprobe
*p
, struct pt_regs
*regs
,
1053 unsigned long flags
)
1057 list_for_each_entry_rcu(kp
, &p
->list
, list
) {
1058 if (kp
->post_handler
&& likely(!kprobe_disabled(kp
))) {
1059 set_kprobe_instance(kp
);
1060 kp
->post_handler(kp
, regs
, flags
);
1061 reset_kprobe_instance();
1065 NOKPROBE_SYMBOL(aggr_post_handler
);
1067 static int aggr_fault_handler(struct kprobe
*p
, struct pt_regs
*regs
,
1070 struct kprobe
*cur
= __this_cpu_read(kprobe_instance
);
1073 * if we faulted "during" the execution of a user specified
1074 * probe handler, invoke just that probe's fault handler
1076 if (cur
&& cur
->fault_handler
) {
1077 if (cur
->fault_handler(cur
, regs
, trapnr
))
1082 NOKPROBE_SYMBOL(aggr_fault_handler
);
1084 static int aggr_break_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1086 struct kprobe
*cur
= __this_cpu_read(kprobe_instance
);
1089 if (cur
&& cur
->break_handler
) {
1090 if (cur
->break_handler(cur
, regs
))
1093 reset_kprobe_instance();
1096 NOKPROBE_SYMBOL(aggr_break_handler
);
1098 /* Walks the list and increments nmissed count for multiprobe case */
1099 void kprobes_inc_nmissed_count(struct kprobe
*p
)
1102 if (!kprobe_aggrprobe(p
)) {
1105 list_for_each_entry_rcu(kp
, &p
->list
, list
)
1110 NOKPROBE_SYMBOL(kprobes_inc_nmissed_count
);
1112 void recycle_rp_inst(struct kretprobe_instance
*ri
,
1113 struct hlist_head
*head
)
1115 struct kretprobe
*rp
= ri
->rp
;
1117 /* remove rp inst off the rprobe_inst_table */
1118 hlist_del(&ri
->hlist
);
1119 INIT_HLIST_NODE(&ri
->hlist
);
1121 raw_spin_lock(&rp
->lock
);
1122 hlist_add_head(&ri
->hlist
, &rp
->free_instances
);
1123 raw_spin_unlock(&rp
->lock
);
1126 hlist_add_head(&ri
->hlist
, head
);
1128 NOKPROBE_SYMBOL(recycle_rp_inst
);
1130 void kretprobe_hash_lock(struct task_struct
*tsk
,
1131 struct hlist_head
**head
, unsigned long *flags
)
1132 __acquires(hlist_lock
)
1134 unsigned long hash
= hash_ptr(tsk
, KPROBE_HASH_BITS
);
1135 raw_spinlock_t
*hlist_lock
;
1137 *head
= &kretprobe_inst_table
[hash
];
1138 hlist_lock
= kretprobe_table_lock_ptr(hash
);
1139 raw_spin_lock_irqsave(hlist_lock
, *flags
);
1141 NOKPROBE_SYMBOL(kretprobe_hash_lock
);
1143 static void kretprobe_table_lock(unsigned long hash
,
1144 unsigned long *flags
)
1145 __acquires(hlist_lock
)
1147 raw_spinlock_t
*hlist_lock
= kretprobe_table_lock_ptr(hash
);
1148 raw_spin_lock_irqsave(hlist_lock
, *flags
);
1150 NOKPROBE_SYMBOL(kretprobe_table_lock
);
1152 void kretprobe_hash_unlock(struct task_struct
*tsk
,
1153 unsigned long *flags
)
1154 __releases(hlist_lock
)
1156 unsigned long hash
= hash_ptr(tsk
, KPROBE_HASH_BITS
);
1157 raw_spinlock_t
*hlist_lock
;
1159 hlist_lock
= kretprobe_table_lock_ptr(hash
);
1160 raw_spin_unlock_irqrestore(hlist_lock
, *flags
);
1162 NOKPROBE_SYMBOL(kretprobe_hash_unlock
);
1164 static void kretprobe_table_unlock(unsigned long hash
,
1165 unsigned long *flags
)
1166 __releases(hlist_lock
)
1168 raw_spinlock_t
*hlist_lock
= kretprobe_table_lock_ptr(hash
);
1169 raw_spin_unlock_irqrestore(hlist_lock
, *flags
);
1171 NOKPROBE_SYMBOL(kretprobe_table_unlock
);
1174 * This function is called from finish_task_switch when task tk becomes dead,
1175 * so that we can recycle any function-return probe instances associated
1176 * with this task. These left over instances represent probed functions
1177 * that have been called but will never return.
1179 void kprobe_flush_task(struct task_struct
*tk
)
1181 struct kretprobe_instance
*ri
;
1182 struct hlist_head
*head
, empty_rp
;
1183 struct hlist_node
*tmp
;
1184 unsigned long hash
, flags
= 0;
1186 if (unlikely(!kprobes_initialized
))
1187 /* Early boot. kretprobe_table_locks not yet initialized. */
1190 INIT_HLIST_HEAD(&empty_rp
);
1191 hash
= hash_ptr(tk
, KPROBE_HASH_BITS
);
1192 head
= &kretprobe_inst_table
[hash
];
1193 kretprobe_table_lock(hash
, &flags
);
1194 hlist_for_each_entry_safe(ri
, tmp
, head
, hlist
) {
1196 recycle_rp_inst(ri
, &empty_rp
);
1198 kretprobe_table_unlock(hash
, &flags
);
1199 hlist_for_each_entry_safe(ri
, tmp
, &empty_rp
, hlist
) {
1200 hlist_del(&ri
->hlist
);
1204 NOKPROBE_SYMBOL(kprobe_flush_task
);
1206 static inline void free_rp_inst(struct kretprobe
*rp
)
1208 struct kretprobe_instance
*ri
;
1209 struct hlist_node
*next
;
1211 hlist_for_each_entry_safe(ri
, next
, &rp
->free_instances
, hlist
) {
1212 hlist_del(&ri
->hlist
);
1217 static void cleanup_rp_inst(struct kretprobe
*rp
)
1219 unsigned long flags
, hash
;
1220 struct kretprobe_instance
*ri
;
1221 struct hlist_node
*next
;
1222 struct hlist_head
*head
;
1225 for (hash
= 0; hash
< KPROBE_TABLE_SIZE
; hash
++) {
1226 kretprobe_table_lock(hash
, &flags
);
1227 head
= &kretprobe_inst_table
[hash
];
1228 hlist_for_each_entry_safe(ri
, next
, head
, hlist
) {
1232 kretprobe_table_unlock(hash
, &flags
);
1236 NOKPROBE_SYMBOL(cleanup_rp_inst
);
1239 * Add the new probe to ap->list. Fail if this is the
1240 * second jprobe at the address - two jprobes can't coexist
1242 static int add_new_kprobe(struct kprobe
*ap
, struct kprobe
*p
)
1244 BUG_ON(kprobe_gone(ap
) || kprobe_gone(p
));
1246 if (p
->break_handler
|| p
->post_handler
)
1247 unoptimize_kprobe(ap
, true); /* Fall back to normal kprobe */
1249 if (p
->break_handler
) {
1250 if (ap
->break_handler
)
1252 list_add_tail_rcu(&p
->list
, &ap
->list
);
1253 ap
->break_handler
= aggr_break_handler
;
1255 list_add_rcu(&p
->list
, &ap
->list
);
1256 if (p
->post_handler
&& !ap
->post_handler
)
1257 ap
->post_handler
= aggr_post_handler
;
1263 * Fill in the required fields of the "manager kprobe". Replace the
1264 * earlier kprobe in the hlist with the manager kprobe
1266 static void init_aggr_kprobe(struct kprobe
*ap
, struct kprobe
*p
)
1268 /* Copy p's insn slot to ap */
1270 flush_insn_slot(ap
);
1272 ap
->flags
= p
->flags
& ~KPROBE_FLAG_OPTIMIZED
;
1273 ap
->pre_handler
= aggr_pre_handler
;
1274 ap
->fault_handler
= aggr_fault_handler
;
1275 /* We don't care the kprobe which has gone. */
1276 if (p
->post_handler
&& !kprobe_gone(p
))
1277 ap
->post_handler
= aggr_post_handler
;
1278 if (p
->break_handler
&& !kprobe_gone(p
))
1279 ap
->break_handler
= aggr_break_handler
;
1281 INIT_LIST_HEAD(&ap
->list
);
1282 INIT_HLIST_NODE(&ap
->hlist
);
1284 list_add_rcu(&p
->list
, &ap
->list
);
1285 hlist_replace_rcu(&p
->hlist
, &ap
->hlist
);
1289 * This is the second or subsequent kprobe at the address - handle
1292 static int register_aggr_kprobe(struct kprobe
*orig_p
, struct kprobe
*p
)
1295 struct kprobe
*ap
= orig_p
;
1297 /* For preparing optimization, jump_label_text_reserved() is called */
1300 * Get online CPUs to avoid text_mutex deadlock.with stop machine,
1301 * which is invoked by unoptimize_kprobe() in add_new_kprobe()
1304 mutex_lock(&text_mutex
);
1306 if (!kprobe_aggrprobe(orig_p
)) {
1307 /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1308 ap
= alloc_aggr_kprobe(orig_p
);
1313 init_aggr_kprobe(ap
, orig_p
);
1314 } else if (kprobe_unused(ap
))
1315 /* This probe is going to die. Rescue it */
1316 reuse_unused_kprobe(ap
);
1318 if (kprobe_gone(ap
)) {
1320 * Attempting to insert new probe at the same location that
1321 * had a probe in the module vaddr area which already
1322 * freed. So, the instruction slot has already been
1323 * released. We need a new slot for the new probe.
1325 ret
= arch_prepare_kprobe(ap
);
1328 * Even if fail to allocate new slot, don't need to
1329 * free aggr_probe. It will be used next time, or
1330 * freed by unregister_kprobe.
1334 /* Prepare optimized instructions if possible. */
1335 prepare_optimized_kprobe(ap
);
1338 * Clear gone flag to prevent allocating new slot again, and
1339 * set disabled flag because it is not armed yet.
1341 ap
->flags
= (ap
->flags
& ~KPROBE_FLAG_GONE
)
1342 | KPROBE_FLAG_DISABLED
;
1345 /* Copy ap's insn slot to p */
1347 ret
= add_new_kprobe(ap
, p
);
1350 mutex_unlock(&text_mutex
);
1352 jump_label_unlock();
1354 if (ret
== 0 && kprobe_disabled(ap
) && !kprobe_disabled(p
)) {
1355 ap
->flags
&= ~KPROBE_FLAG_DISABLED
;
1356 if (!kprobes_all_disarmed
)
1357 /* Arm the breakpoint again. */
1363 bool __weak
arch_within_kprobe_blacklist(unsigned long addr
)
1365 /* The __kprobes marked functions and entry code must not be probed */
1366 return addr
>= (unsigned long)__kprobes_text_start
&&
1367 addr
< (unsigned long)__kprobes_text_end
;
1370 bool within_kprobe_blacklist(unsigned long addr
)
1372 struct kprobe_blacklist_entry
*ent
;
1374 if (arch_within_kprobe_blacklist(addr
))
1377 * If there exists a kprobe_blacklist, verify and
1378 * fail any probe registration in the prohibited area
1380 list_for_each_entry(ent
, &kprobe_blacklist
, list
) {
1381 if (addr
>= ent
->start_addr
&& addr
< ent
->end_addr
)
1389 * If we have a symbol_name argument, look it up and add the offset field
1390 * to it. This way, we can specify a relative address to a symbol.
1391 * This returns encoded errors if it fails to look up symbol or invalid
1392 * combination of parameters.
1394 static kprobe_opcode_t
*_kprobe_addr(kprobe_opcode_t
*addr
,
1395 const char *symbol_name
, unsigned int offset
)
1397 if ((symbol_name
&& addr
) || (!symbol_name
&& !addr
))
1401 kprobe_lookup_name(symbol_name
, addr
);
1403 return ERR_PTR(-ENOENT
);
1406 addr
= (kprobe_opcode_t
*)(((char *)addr
) + offset
);
1411 return ERR_PTR(-EINVAL
);
1414 static kprobe_opcode_t
*kprobe_addr(struct kprobe
*p
)
1416 return _kprobe_addr(p
->addr
, p
->symbol_name
, p
->offset
);
1419 /* Check passed kprobe is valid and return kprobe in kprobe_table. */
1420 static struct kprobe
*__get_valid_kprobe(struct kprobe
*p
)
1422 struct kprobe
*ap
, *list_p
;
1424 ap
= get_kprobe(p
->addr
);
1429 list_for_each_entry_rcu(list_p
, &ap
->list
, list
)
1431 /* kprobe p is a valid probe */
1439 /* Return error if the kprobe is being re-registered */
1440 static inline int check_kprobe_rereg(struct kprobe
*p
)
1444 mutex_lock(&kprobe_mutex
);
1445 if (__get_valid_kprobe(p
))
1447 mutex_unlock(&kprobe_mutex
);
1452 int __weak
arch_check_ftrace_location(struct kprobe
*p
)
1454 unsigned long ftrace_addr
;
1456 ftrace_addr
= ftrace_location((unsigned long)p
->addr
);
1458 #ifdef CONFIG_KPROBES_ON_FTRACE
1459 /* Given address is not on the instruction boundary */
1460 if ((unsigned long)p
->addr
!= ftrace_addr
)
1462 p
->flags
|= KPROBE_FLAG_FTRACE
;
1463 #else /* !CONFIG_KPROBES_ON_FTRACE */
1470 static int check_kprobe_address_safe(struct kprobe
*p
,
1471 struct module
**probed_mod
)
1475 ret
= arch_check_ftrace_location(p
);
1481 /* Ensure it is not in reserved area nor out of text */
1482 if (!kernel_text_address((unsigned long) p
->addr
) ||
1483 within_kprobe_blacklist((unsigned long) p
->addr
) ||
1484 jump_label_text_reserved(p
->addr
, p
->addr
)) {
1489 /* Check if are we probing a module */
1490 *probed_mod
= __module_text_address((unsigned long) p
->addr
);
1493 * We must hold a refcount of the probed module while updating
1494 * its code to prohibit unexpected unloading.
1496 if (unlikely(!try_module_get(*probed_mod
))) {
1502 * If the module freed .init.text, we couldn't insert
1505 if (within_module_init((unsigned long)p
->addr
, *probed_mod
) &&
1506 (*probed_mod
)->state
!= MODULE_STATE_COMING
) {
1507 module_put(*probed_mod
);
1514 jump_label_unlock();
1519 int register_kprobe(struct kprobe
*p
)
1522 struct kprobe
*old_p
;
1523 struct module
*probed_mod
;
1524 kprobe_opcode_t
*addr
;
1526 /* Adjust probe address from symbol */
1527 addr
= kprobe_addr(p
);
1529 return PTR_ERR(addr
);
1532 ret
= check_kprobe_rereg(p
);
1536 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1537 p
->flags
&= KPROBE_FLAG_DISABLED
;
1539 INIT_LIST_HEAD(&p
->list
);
1541 ret
= check_kprobe_address_safe(p
, &probed_mod
);
1545 mutex_lock(&kprobe_mutex
);
1547 old_p
= get_kprobe(p
->addr
);
1549 /* Since this may unoptimize old_p, locking text_mutex. */
1550 ret
= register_aggr_kprobe(old_p
, p
);
1554 mutex_lock(&text_mutex
); /* Avoiding text modification */
1555 ret
= prepare_kprobe(p
);
1556 mutex_unlock(&text_mutex
);
1560 INIT_HLIST_NODE(&p
->hlist
);
1561 hlist_add_head_rcu(&p
->hlist
,
1562 &kprobe_table
[hash_ptr(p
->addr
, KPROBE_HASH_BITS
)]);
1564 if (!kprobes_all_disarmed
&& !kprobe_disabled(p
))
1567 /* Try to optimize kprobe */
1568 try_to_optimize_kprobe(p
);
1571 mutex_unlock(&kprobe_mutex
);
1574 module_put(probed_mod
);
1578 EXPORT_SYMBOL_GPL(register_kprobe
);
1580 /* Check if all probes on the aggrprobe are disabled */
1581 static int aggr_kprobe_disabled(struct kprobe
*ap
)
1585 list_for_each_entry_rcu(kp
, &ap
->list
, list
)
1586 if (!kprobe_disabled(kp
))
1588 * There is an active probe on the list.
1589 * We can't disable this ap.
1596 /* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1597 static struct kprobe
*__disable_kprobe(struct kprobe
*p
)
1599 struct kprobe
*orig_p
;
1601 /* Get an original kprobe for return */
1602 orig_p
= __get_valid_kprobe(p
);
1603 if (unlikely(orig_p
== NULL
))
1606 if (!kprobe_disabled(p
)) {
1607 /* Disable probe if it is a child probe */
1609 p
->flags
|= KPROBE_FLAG_DISABLED
;
1611 /* Try to disarm and disable this/parent probe */
1612 if (p
== orig_p
|| aggr_kprobe_disabled(orig_p
)) {
1614 * If kprobes_all_disarmed is set, orig_p
1615 * should have already been disarmed, so
1616 * skip unneed disarming process.
1618 if (!kprobes_all_disarmed
)
1619 disarm_kprobe(orig_p
, true);
1620 orig_p
->flags
|= KPROBE_FLAG_DISABLED
;
1628 * Unregister a kprobe without a scheduler synchronization.
1630 static int __unregister_kprobe_top(struct kprobe
*p
)
1632 struct kprobe
*ap
, *list_p
;
1634 /* Disable kprobe. This will disarm it if needed. */
1635 ap
= __disable_kprobe(p
);
1641 * This probe is an independent(and non-optimized) kprobe
1642 * (not an aggrprobe). Remove from the hash list.
1646 /* Following process expects this probe is an aggrprobe */
1647 WARN_ON(!kprobe_aggrprobe(ap
));
1649 if (list_is_singular(&ap
->list
) && kprobe_disarmed(ap
))
1651 * !disarmed could be happen if the probe is under delayed
1656 /* If disabling probe has special handlers, update aggrprobe */
1657 if (p
->break_handler
&& !kprobe_gone(p
))
1658 ap
->break_handler
= NULL
;
1659 if (p
->post_handler
&& !kprobe_gone(p
)) {
1660 list_for_each_entry_rcu(list_p
, &ap
->list
, list
) {
1661 if ((list_p
!= p
) && (list_p
->post_handler
))
1664 ap
->post_handler
= NULL
;
1668 * Remove from the aggrprobe: this path will do nothing in
1669 * __unregister_kprobe_bottom().
1671 list_del_rcu(&p
->list
);
1672 if (!kprobe_disabled(ap
) && !kprobes_all_disarmed
)
1674 * Try to optimize this probe again, because post
1675 * handler may have been changed.
1677 optimize_kprobe(ap
);
1682 BUG_ON(!kprobe_disarmed(ap
));
1683 hlist_del_rcu(&ap
->hlist
);
1687 static void __unregister_kprobe_bottom(struct kprobe
*p
)
1691 if (list_empty(&p
->list
))
1692 /* This is an independent kprobe */
1693 arch_remove_kprobe(p
);
1694 else if (list_is_singular(&p
->list
)) {
1695 /* This is the last child of an aggrprobe */
1696 ap
= list_entry(p
->list
.next
, struct kprobe
, list
);
1698 free_aggr_kprobe(ap
);
1700 /* Otherwise, do nothing. */
1703 int register_kprobes(struct kprobe
**kps
, int num
)
1709 for (i
= 0; i
< num
; i
++) {
1710 ret
= register_kprobe(kps
[i
]);
1713 unregister_kprobes(kps
, i
);
1719 EXPORT_SYMBOL_GPL(register_kprobes
);
1721 void unregister_kprobe(struct kprobe
*p
)
1723 unregister_kprobes(&p
, 1);
1725 EXPORT_SYMBOL_GPL(unregister_kprobe
);
1727 void unregister_kprobes(struct kprobe
**kps
, int num
)
1733 mutex_lock(&kprobe_mutex
);
1734 for (i
= 0; i
< num
; i
++)
1735 if (__unregister_kprobe_top(kps
[i
]) < 0)
1736 kps
[i
]->addr
= NULL
;
1737 mutex_unlock(&kprobe_mutex
);
1739 synchronize_sched();
1740 for (i
= 0; i
< num
; i
++)
1742 __unregister_kprobe_bottom(kps
[i
]);
1744 EXPORT_SYMBOL_GPL(unregister_kprobes
);
1746 int __weak
kprobe_exceptions_notify(struct notifier_block
*self
,
1747 unsigned long val
, void *data
)
1751 NOKPROBE_SYMBOL(kprobe_exceptions_notify
);
1753 static struct notifier_block kprobe_exceptions_nb
= {
1754 .notifier_call
= kprobe_exceptions_notify
,
1755 .priority
= 0x7fffffff /* we need to be notified first */
1758 unsigned long __weak
arch_deref_entry_point(void *entry
)
1760 return (unsigned long)entry
;
1763 int register_jprobes(struct jprobe
**jps
, int num
)
1770 for (i
= 0; i
< num
; i
++) {
1771 unsigned long addr
, offset
;
1773 addr
= arch_deref_entry_point(jp
->entry
);
1775 /* Verify probepoint is a function entry point */
1776 if (kallsyms_lookup_size_offset(addr
, NULL
, &offset
) &&
1778 jp
->kp
.pre_handler
= setjmp_pre_handler
;
1779 jp
->kp
.break_handler
= longjmp_break_handler
;
1780 ret
= register_kprobe(&jp
->kp
);
1786 unregister_jprobes(jps
, i
);
1792 EXPORT_SYMBOL_GPL(register_jprobes
);
1794 int register_jprobe(struct jprobe
*jp
)
1796 return register_jprobes(&jp
, 1);
1798 EXPORT_SYMBOL_GPL(register_jprobe
);
1800 void unregister_jprobe(struct jprobe
*jp
)
1802 unregister_jprobes(&jp
, 1);
1804 EXPORT_SYMBOL_GPL(unregister_jprobe
);
1806 void unregister_jprobes(struct jprobe
**jps
, int num
)
1812 mutex_lock(&kprobe_mutex
);
1813 for (i
= 0; i
< num
; i
++)
1814 if (__unregister_kprobe_top(&jps
[i
]->kp
) < 0)
1815 jps
[i
]->kp
.addr
= NULL
;
1816 mutex_unlock(&kprobe_mutex
);
1818 synchronize_sched();
1819 for (i
= 0; i
< num
; i
++) {
1820 if (jps
[i
]->kp
.addr
)
1821 __unregister_kprobe_bottom(&jps
[i
]->kp
);
1824 EXPORT_SYMBOL_GPL(unregister_jprobes
);
1826 #ifdef CONFIG_KRETPROBES
1828 * This kprobe pre_handler is registered with every kretprobe. When probe
1829 * hits it will set up the return probe.
1831 static int pre_handler_kretprobe(struct kprobe
*p
, struct pt_regs
*regs
)
1833 struct kretprobe
*rp
= container_of(p
, struct kretprobe
, kp
);
1834 unsigned long hash
, flags
= 0;
1835 struct kretprobe_instance
*ri
;
1838 * To avoid deadlocks, prohibit return probing in NMI contexts,
1839 * just skip the probe and increase the (inexact) 'nmissed'
1840 * statistical counter, so that the user is informed that
1841 * something happened:
1843 if (unlikely(in_nmi())) {
1848 /* TODO: consider to only swap the RA after the last pre_handler fired */
1849 hash
= hash_ptr(current
, KPROBE_HASH_BITS
);
1850 raw_spin_lock_irqsave(&rp
->lock
, flags
);
1851 if (!hlist_empty(&rp
->free_instances
)) {
1852 ri
= hlist_entry(rp
->free_instances
.first
,
1853 struct kretprobe_instance
, hlist
);
1854 hlist_del(&ri
->hlist
);
1855 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1860 if (rp
->entry_handler
&& rp
->entry_handler(ri
, regs
)) {
1861 raw_spin_lock_irqsave(&rp
->lock
, flags
);
1862 hlist_add_head(&ri
->hlist
, &rp
->free_instances
);
1863 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1867 arch_prepare_kretprobe(ri
, regs
);
1869 /* XXX(hch): why is there no hlist_move_head? */
1870 INIT_HLIST_NODE(&ri
->hlist
);
1871 kretprobe_table_lock(hash
, &flags
);
1872 hlist_add_head(&ri
->hlist
, &kretprobe_inst_table
[hash
]);
1873 kretprobe_table_unlock(hash
, &flags
);
1876 raw_spin_unlock_irqrestore(&rp
->lock
, flags
);
1880 NOKPROBE_SYMBOL(pre_handler_kretprobe
);
1882 bool __weak
arch_function_offset_within_entry(unsigned long offset
)
1887 bool function_offset_within_entry(kprobe_opcode_t
*addr
, const char *sym
, unsigned long offset
)
1889 kprobe_opcode_t
*kp_addr
= _kprobe_addr(addr
, sym
, offset
);
1891 if (IS_ERR(kp_addr
))
1894 if (!kallsyms_lookup_size_offset((unsigned long)kp_addr
, NULL
, &offset
) ||
1895 !arch_function_offset_within_entry(offset
))
1901 int register_kretprobe(struct kretprobe
*rp
)
1904 struct kretprobe_instance
*inst
;
1908 if (!function_offset_within_entry(rp
->kp
.addr
, rp
->kp
.symbol_name
, rp
->kp
.offset
))
1911 if (kretprobe_blacklist_size
) {
1912 addr
= kprobe_addr(&rp
->kp
);
1914 return PTR_ERR(addr
);
1916 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
1917 if (kretprobe_blacklist
[i
].addr
== addr
)
1922 rp
->kp
.pre_handler
= pre_handler_kretprobe
;
1923 rp
->kp
.post_handler
= NULL
;
1924 rp
->kp
.fault_handler
= NULL
;
1925 rp
->kp
.break_handler
= NULL
;
1927 /* Pre-allocate memory for max kretprobe instances */
1928 if (rp
->maxactive
<= 0) {
1929 #ifdef CONFIG_PREEMPT
1930 rp
->maxactive
= max_t(unsigned int, 10, 2*num_possible_cpus());
1932 rp
->maxactive
= num_possible_cpus();
1935 raw_spin_lock_init(&rp
->lock
);
1936 INIT_HLIST_HEAD(&rp
->free_instances
);
1937 for (i
= 0; i
< rp
->maxactive
; i
++) {
1938 inst
= kmalloc(sizeof(struct kretprobe_instance
) +
1939 rp
->data_size
, GFP_KERNEL
);
1944 INIT_HLIST_NODE(&inst
->hlist
);
1945 hlist_add_head(&inst
->hlist
, &rp
->free_instances
);
1949 /* Establish function entry probe point */
1950 ret
= register_kprobe(&rp
->kp
);
1955 EXPORT_SYMBOL_GPL(register_kretprobe
);
1957 int register_kretprobes(struct kretprobe
**rps
, int num
)
1963 for (i
= 0; i
< num
; i
++) {
1964 ret
= register_kretprobe(rps
[i
]);
1967 unregister_kretprobes(rps
, i
);
1973 EXPORT_SYMBOL_GPL(register_kretprobes
);
1975 void unregister_kretprobe(struct kretprobe
*rp
)
1977 unregister_kretprobes(&rp
, 1);
1979 EXPORT_SYMBOL_GPL(unregister_kretprobe
);
1981 void unregister_kretprobes(struct kretprobe
**rps
, int num
)
1987 mutex_lock(&kprobe_mutex
);
1988 for (i
= 0; i
< num
; i
++)
1989 if (__unregister_kprobe_top(&rps
[i
]->kp
) < 0)
1990 rps
[i
]->kp
.addr
= NULL
;
1991 mutex_unlock(&kprobe_mutex
);
1993 synchronize_sched();
1994 for (i
= 0; i
< num
; i
++) {
1995 if (rps
[i
]->kp
.addr
) {
1996 __unregister_kprobe_bottom(&rps
[i
]->kp
);
1997 cleanup_rp_inst(rps
[i
]);
2001 EXPORT_SYMBOL_GPL(unregister_kretprobes
);
2003 #else /* CONFIG_KRETPROBES */
2004 int register_kretprobe(struct kretprobe
*rp
)
2008 EXPORT_SYMBOL_GPL(register_kretprobe
);
2010 int register_kretprobes(struct kretprobe
**rps
, int num
)
2014 EXPORT_SYMBOL_GPL(register_kretprobes
);
2016 void unregister_kretprobe(struct kretprobe
*rp
)
2019 EXPORT_SYMBOL_GPL(unregister_kretprobe
);
2021 void unregister_kretprobes(struct kretprobe
**rps
, int num
)
2024 EXPORT_SYMBOL_GPL(unregister_kretprobes
);
2026 static int pre_handler_kretprobe(struct kprobe
*p
, struct pt_regs
*regs
)
2030 NOKPROBE_SYMBOL(pre_handler_kretprobe
);
2032 #endif /* CONFIG_KRETPROBES */
2034 /* Set the kprobe gone and remove its instruction buffer. */
2035 static void kill_kprobe(struct kprobe
*p
)
2039 p
->flags
|= KPROBE_FLAG_GONE
;
2040 if (kprobe_aggrprobe(p
)) {
2042 * If this is an aggr_kprobe, we have to list all the
2043 * chained probes and mark them GONE.
2045 list_for_each_entry_rcu(kp
, &p
->list
, list
)
2046 kp
->flags
|= KPROBE_FLAG_GONE
;
2047 p
->post_handler
= NULL
;
2048 p
->break_handler
= NULL
;
2049 kill_optimized_kprobe(p
);
2052 * Here, we can remove insn_slot safely, because no thread calls
2053 * the original probed function (which will be freed soon) any more.
2055 arch_remove_kprobe(p
);
2058 /* Disable one kprobe */
2059 int disable_kprobe(struct kprobe
*kp
)
2063 mutex_lock(&kprobe_mutex
);
2065 /* Disable this kprobe */
2066 if (__disable_kprobe(kp
) == NULL
)
2069 mutex_unlock(&kprobe_mutex
);
2072 EXPORT_SYMBOL_GPL(disable_kprobe
);
2074 /* Enable one kprobe */
2075 int enable_kprobe(struct kprobe
*kp
)
2080 mutex_lock(&kprobe_mutex
);
2082 /* Check whether specified probe is valid. */
2083 p
= __get_valid_kprobe(kp
);
2084 if (unlikely(p
== NULL
)) {
2089 if (kprobe_gone(kp
)) {
2090 /* This kprobe has gone, we couldn't enable it. */
2096 kp
->flags
&= ~KPROBE_FLAG_DISABLED
;
2098 if (!kprobes_all_disarmed
&& kprobe_disabled(p
)) {
2099 p
->flags
&= ~KPROBE_FLAG_DISABLED
;
2103 mutex_unlock(&kprobe_mutex
);
2106 EXPORT_SYMBOL_GPL(enable_kprobe
);
2108 void dump_kprobe(struct kprobe
*kp
)
2110 printk(KERN_WARNING
"Dumping kprobe:\n");
2111 printk(KERN_WARNING
"Name: %s\nAddress: %p\nOffset: %x\n",
2112 kp
->symbol_name
, kp
->addr
, kp
->offset
);
2114 NOKPROBE_SYMBOL(dump_kprobe
);
2117 * Lookup and populate the kprobe_blacklist.
2119 * Unlike the kretprobe blacklist, we'll need to determine
2120 * the range of addresses that belong to the said functions,
2121 * since a kprobe need not necessarily be at the beginning
2124 static int __init
populate_kprobe_blacklist(unsigned long *start
,
2127 unsigned long *iter
;
2128 struct kprobe_blacklist_entry
*ent
;
2129 unsigned long entry
, offset
= 0, size
= 0;
2131 for (iter
= start
; iter
< end
; iter
++) {
2132 entry
= arch_deref_entry_point((void *)*iter
);
2134 if (!kernel_text_address(entry
) ||
2135 !kallsyms_lookup_size_offset(entry
, &size
, &offset
)) {
2136 pr_err("Failed to find blacklist at %p\n",
2141 ent
= kmalloc(sizeof(*ent
), GFP_KERNEL
);
2144 ent
->start_addr
= entry
;
2145 ent
->end_addr
= entry
+ size
;
2146 INIT_LIST_HEAD(&ent
->list
);
2147 list_add_tail(&ent
->list
, &kprobe_blacklist
);
2152 /* Module notifier call back, checking kprobes on the module */
2153 static int kprobes_module_callback(struct notifier_block
*nb
,
2154 unsigned long val
, void *data
)
2156 struct module
*mod
= data
;
2157 struct hlist_head
*head
;
2160 int checkcore
= (val
== MODULE_STATE_GOING
);
2162 if (val
!= MODULE_STATE_GOING
&& val
!= MODULE_STATE_LIVE
)
2166 * When MODULE_STATE_GOING was notified, both of module .text and
2167 * .init.text sections would be freed. When MODULE_STATE_LIVE was
2168 * notified, only .init.text section would be freed. We need to
2169 * disable kprobes which have been inserted in the sections.
2171 mutex_lock(&kprobe_mutex
);
2172 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2173 head
= &kprobe_table
[i
];
2174 hlist_for_each_entry_rcu(p
, head
, hlist
)
2175 if (within_module_init((unsigned long)p
->addr
, mod
) ||
2177 within_module_core((unsigned long)p
->addr
, mod
))) {
2179 * The vaddr this probe is installed will soon
2180 * be vfreed buy not synced to disk. Hence,
2181 * disarming the breakpoint isn't needed.
2186 mutex_unlock(&kprobe_mutex
);
2190 static struct notifier_block kprobe_module_nb
= {
2191 .notifier_call
= kprobes_module_callback
,
2195 /* Markers of _kprobe_blacklist section */
2196 extern unsigned long __start_kprobe_blacklist
[];
2197 extern unsigned long __stop_kprobe_blacklist
[];
2199 static int __init
init_kprobes(void)
2203 /* FIXME allocate the probe table, currently defined statically */
2204 /* initialize all list heads */
2205 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2206 INIT_HLIST_HEAD(&kprobe_table
[i
]);
2207 INIT_HLIST_HEAD(&kretprobe_inst_table
[i
]);
2208 raw_spin_lock_init(&(kretprobe_table_locks
[i
].lock
));
2211 err
= populate_kprobe_blacklist(__start_kprobe_blacklist
,
2212 __stop_kprobe_blacklist
);
2214 pr_err("kprobes: failed to populate blacklist: %d\n", err
);
2215 pr_err("Please take care of using kprobes.\n");
2218 if (kretprobe_blacklist_size
) {
2219 /* lookup the function address from its name */
2220 for (i
= 0; kretprobe_blacklist
[i
].name
!= NULL
; i
++) {
2221 kprobe_lookup_name(kretprobe_blacklist
[i
].name
,
2222 kretprobe_blacklist
[i
].addr
);
2223 if (!kretprobe_blacklist
[i
].addr
)
2224 printk("kretprobe: lookup failed: %s\n",
2225 kretprobe_blacklist
[i
].name
);
2229 #if defined(CONFIG_OPTPROBES)
2230 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2231 /* Init kprobe_optinsn_slots */
2232 kprobe_optinsn_slots
.insn_size
= MAX_OPTINSN_SIZE
;
2234 /* By default, kprobes can be optimized */
2235 kprobes_allow_optimization
= true;
2238 /* By default, kprobes are armed */
2239 kprobes_all_disarmed
= false;
2241 err
= arch_init_kprobes();
2243 err
= register_die_notifier(&kprobe_exceptions_nb
);
2245 err
= register_module_notifier(&kprobe_module_nb
);
2247 kprobes_initialized
= (err
== 0);
2254 #ifdef CONFIG_DEBUG_FS
2255 static void report_probe(struct seq_file
*pi
, struct kprobe
*p
,
2256 const char *sym
, int offset
, char *modname
, struct kprobe
*pp
)
2260 if (p
->pre_handler
== pre_handler_kretprobe
)
2262 else if (p
->pre_handler
== setjmp_pre_handler
)
2268 seq_printf(pi
, "%p %s %s+0x%x %s ",
2269 p
->addr
, kprobe_type
, sym
, offset
,
2270 (modname
? modname
: " "));
2272 seq_printf(pi
, "%p %s %p ",
2273 p
->addr
, kprobe_type
, p
->addr
);
2277 seq_printf(pi
, "%s%s%s%s\n",
2278 (kprobe_gone(p
) ? "[GONE]" : ""),
2279 ((kprobe_disabled(p
) && !kprobe_gone(p
)) ? "[DISABLED]" : ""),
2280 (kprobe_optimized(pp
) ? "[OPTIMIZED]" : ""),
2281 (kprobe_ftrace(pp
) ? "[FTRACE]" : ""));
2284 static void *kprobe_seq_start(struct seq_file
*f
, loff_t
*pos
)
2286 return (*pos
< KPROBE_TABLE_SIZE
) ? pos
: NULL
;
2289 static void *kprobe_seq_next(struct seq_file
*f
, void *v
, loff_t
*pos
)
2292 if (*pos
>= KPROBE_TABLE_SIZE
)
2297 static void kprobe_seq_stop(struct seq_file
*f
, void *v
)
2302 static int show_kprobe_addr(struct seq_file
*pi
, void *v
)
2304 struct hlist_head
*head
;
2305 struct kprobe
*p
, *kp
;
2306 const char *sym
= NULL
;
2307 unsigned int i
= *(loff_t
*) v
;
2308 unsigned long offset
= 0;
2309 char *modname
, namebuf
[KSYM_NAME_LEN
];
2311 head
= &kprobe_table
[i
];
2313 hlist_for_each_entry_rcu(p
, head
, hlist
) {
2314 sym
= kallsyms_lookup((unsigned long)p
->addr
, NULL
,
2315 &offset
, &modname
, namebuf
);
2316 if (kprobe_aggrprobe(p
)) {
2317 list_for_each_entry_rcu(kp
, &p
->list
, list
)
2318 report_probe(pi
, kp
, sym
, offset
, modname
, p
);
2320 report_probe(pi
, p
, sym
, offset
, modname
, NULL
);
2326 static const struct seq_operations kprobes_seq_ops
= {
2327 .start
= kprobe_seq_start
,
2328 .next
= kprobe_seq_next
,
2329 .stop
= kprobe_seq_stop
,
2330 .show
= show_kprobe_addr
2333 static int kprobes_open(struct inode
*inode
, struct file
*filp
)
2335 return seq_open(filp
, &kprobes_seq_ops
);
2338 static const struct file_operations debugfs_kprobes_operations
= {
2339 .open
= kprobes_open
,
2341 .llseek
= seq_lseek
,
2342 .release
= seq_release
,
2345 /* kprobes/blacklist -- shows which functions can not be probed */
2346 static void *kprobe_blacklist_seq_start(struct seq_file
*m
, loff_t
*pos
)
2348 return seq_list_start(&kprobe_blacklist
, *pos
);
2351 static void *kprobe_blacklist_seq_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
2353 return seq_list_next(v
, &kprobe_blacklist
, pos
);
2356 static int kprobe_blacklist_seq_show(struct seq_file
*m
, void *v
)
2358 struct kprobe_blacklist_entry
*ent
=
2359 list_entry(v
, struct kprobe_blacklist_entry
, list
);
2361 seq_printf(m
, "0x%p-0x%p\t%ps\n", (void *)ent
->start_addr
,
2362 (void *)ent
->end_addr
, (void *)ent
->start_addr
);
2366 static const struct seq_operations kprobe_blacklist_seq_ops
= {
2367 .start
= kprobe_blacklist_seq_start
,
2368 .next
= kprobe_blacklist_seq_next
,
2369 .stop
= kprobe_seq_stop
, /* Reuse void function */
2370 .show
= kprobe_blacklist_seq_show
,
2373 static int kprobe_blacklist_open(struct inode
*inode
, struct file
*filp
)
2375 return seq_open(filp
, &kprobe_blacklist_seq_ops
);
2378 static const struct file_operations debugfs_kprobe_blacklist_ops
= {
2379 .open
= kprobe_blacklist_open
,
2381 .llseek
= seq_lseek
,
2382 .release
= seq_release
,
2385 static void arm_all_kprobes(void)
2387 struct hlist_head
*head
;
2391 mutex_lock(&kprobe_mutex
);
2393 /* If kprobes are armed, just return */
2394 if (!kprobes_all_disarmed
)
2395 goto already_enabled
;
2398 * optimize_kprobe() called by arm_kprobe() checks
2399 * kprobes_all_disarmed, so set kprobes_all_disarmed before
2402 kprobes_all_disarmed
= false;
2403 /* Arming kprobes doesn't optimize kprobe itself */
2404 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2405 head
= &kprobe_table
[i
];
2406 hlist_for_each_entry_rcu(p
, head
, hlist
)
2407 if (!kprobe_disabled(p
))
2411 printk(KERN_INFO
"Kprobes globally enabled\n");
2414 mutex_unlock(&kprobe_mutex
);
2418 static void disarm_all_kprobes(void)
2420 struct hlist_head
*head
;
2424 mutex_lock(&kprobe_mutex
);
2426 /* If kprobes are already disarmed, just return */
2427 if (kprobes_all_disarmed
) {
2428 mutex_unlock(&kprobe_mutex
);
2432 kprobes_all_disarmed
= true;
2433 printk(KERN_INFO
"Kprobes globally disabled\n");
2435 for (i
= 0; i
< KPROBE_TABLE_SIZE
; i
++) {
2436 head
= &kprobe_table
[i
];
2437 hlist_for_each_entry_rcu(p
, head
, hlist
) {
2438 if (!arch_trampoline_kprobe(p
) && !kprobe_disabled(p
))
2439 disarm_kprobe(p
, false);
2442 mutex_unlock(&kprobe_mutex
);
2444 /* Wait for disarming all kprobes by optimizer */
2445 wait_for_kprobe_optimizer();
2449 * XXX: The debugfs bool file interface doesn't allow for callbacks
2450 * when the bool state is switched. We can reuse that facility when
2453 static ssize_t
read_enabled_file_bool(struct file
*file
,
2454 char __user
*user_buf
, size_t count
, loff_t
*ppos
)
2458 if (!kprobes_all_disarmed
)
2464 return simple_read_from_buffer(user_buf
, count
, ppos
, buf
, 2);
2467 static ssize_t
write_enabled_file_bool(struct file
*file
,
2468 const char __user
*user_buf
, size_t count
, loff_t
*ppos
)
2473 buf_size
= min(count
, (sizeof(buf
)-1));
2474 if (copy_from_user(buf
, user_buf
, buf_size
))
2477 buf
[buf_size
] = '\0';
2487 disarm_all_kprobes();
2496 static const struct file_operations fops_kp
= {
2497 .read
= read_enabled_file_bool
,
2498 .write
= write_enabled_file_bool
,
2499 .llseek
= default_llseek
,
2502 static int __init
debugfs_kprobe_init(void)
2504 struct dentry
*dir
, *file
;
2505 unsigned int value
= 1;
2507 dir
= debugfs_create_dir("kprobes", NULL
);
2511 file
= debugfs_create_file("list", 0444, dir
, NULL
,
2512 &debugfs_kprobes_operations
);
2516 file
= debugfs_create_file("enabled", 0600, dir
,
2521 file
= debugfs_create_file("blacklist", 0444, dir
, NULL
,
2522 &debugfs_kprobe_blacklist_ops
);
2529 debugfs_remove(dir
);
2533 late_initcall(debugfs_kprobe_init
);
2534 #endif /* CONFIG_DEBUG_FS */
2536 module_init(init_kprobes
);
2538 /* defined in arch/.../kernel/kprobes.c */
2539 EXPORT_SYMBOL_GPL(jprobe_return
);