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kprobes: Introduce kprobes jump optimization

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Introduce kprobes jump optimization arch-independent parts.
Kprobes uses breakpoint instruction for interrupting execution
flow, on some architectures, it can be replaced by a jump
instruction and interruption emulation code. This gains kprobs'
performance drastically.

To enable this feature, set CONFIG_OPTPROBES=y (default y if the
arch supports OPTPROBE).

Changes in v9:
 - Fix a bug to optimize probe when enabling.
 - Check nearby probes can be optimize/unoptimize when disarming/arming
   kprobes, instead of registering/unregistering. This will help
   kprobe-tracer because most of probes on it are usually disabled.

Changes in v6:
 - Cleanup coding style for readability.
 - Add comments around get/put_online_cpus().

Changes in v5:
 - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex
   deadlock.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Masami Hiramatsu 2010-02-25 08:34:07 -05:00 committed by Ingo Molnar
parent 4610ee1d36
commit afd66255b9
3 changed files with 459 additions and 51 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
arch/Kconfig
View file

@ -57,6 +57,17 @@ config KPROBES
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
config OPTPROBES
bool "Kprobes jump optimization support (EXPERIMENTAL)"
default y
depends on KPROBES
depends on !PREEMPT
depends on HAVE_OPTPROBES
select KALLSYMS_ALL
help
This option will allow kprobes to optimize breakpoint to
a jump for reducing its overhead.
config HAVE_EFFICIENT_UNALIGNED_ACCESS
bool
help
@ -99,6 +110,8 @@ config HAVE_KPROBES
config HAVE_KRETPROBES
bool
config HAVE_OPTPROBES
bool
#
# An arch should select this if it provides all these things:
#

36
include/linux/kprobes.h
View file

@ -122,6 +122,11 @@ struct kprobe {
/* Kprobe status flags */
#define KPROBE_FLAG_GONE 1 /* breakpoint has already gone */
#define KPROBE_FLAG_DISABLED 2 /* probe is temporarily disabled */
#define KPROBE_FLAG_OPTIMIZED 4 /*
* probe is really optimized.
* NOTE:
* this flag is only for optimized_kprobe.
*/
/* Has this kprobe gone ? */
static inline int kprobe_gone(struct kprobe *p)
@ -134,6 +139,12 @@ static inline int kprobe_disabled(struct kprobe *p)
{
return p->flags & (KPROBE_FLAG_DISABLED | KPROBE_FLAG_GONE);
}
/* Is this kprobe really running optimized path ? */
static inline int kprobe_optimized(struct kprobe *p)
{
return p->flags & KPROBE_FLAG_OPTIMIZED;
}
/*
* Special probe type that uses setjmp-longjmp type tricks to resume
* execution at a specified entry with a matching prototype corresponding
@ -249,6 +260,31 @@ extern kprobe_opcode_t *get_insn_slot(void);
extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
#ifdef CONFIG_OPTPROBES
/*
* Internal structure for direct jump optimized probe
*/
struct optimized_kprobe {
struct kprobe kp;
struct list_head list; /* list for optimizing queue */
struct arch_optimized_insn optinsn;
};
/* Architecture dependent functions for direct jump optimization */
extern int arch_prepared_optinsn(struct arch_optimized_insn *optinsn);
extern int arch_check_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_prepare_optimized_kprobe(struct optimized_kprobe *op);
extern void arch_remove_optimized_kprobe(struct optimized_kprobe *op);
extern int arch_optimize_kprobe(struct optimized_kprobe *op);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
extern kprobe_opcode_t *get_optinsn_slot(void);
extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
unsigned long addr);
extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
#endif /* CONFIG_OPTPROBES */
/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
void kretprobe_hash_lock(struct task_struct *tsk,

457
kernel/kprobes.c
View file

@ -45,6 +45,7 @@
#include <linux/kdebug.h>
#include <linux/memory.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <asm-generic/sections.h>
#include <asm/cacheflush.h>
@ -280,6 +281,33 @@ void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
__free_insn_slot(&kprobe_insn_slots, slot, dirty);
mutex_unlock(&kprobe_insn_mutex);
}
#ifdef CONFIG_OPTPROBES
/* For optimized_kprobe buffer */
static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
static struct kprobe_insn_cache kprobe_optinsn_slots = {
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
/* .insn_size is initialized later */
.nr_garbage = 0,
};
/* Get a slot for optimized_kprobe buffer */
kprobe_opcode_t __kprobes *get_optinsn_slot(void)
{
kprobe_opcode_t *ret = NULL;
mutex_lock(&kprobe_optinsn_mutex);
ret = __get_insn_slot(&kprobe_optinsn_slots);
mutex_unlock(&kprobe_optinsn_mutex);
return ret;
}
void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
{
mutex_lock(&kprobe_optinsn_mutex);
__free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
mutex_unlock(&kprobe_optinsn_mutex);
}
#endif
#endif
/* We have preemption disabled.. so it is safe to use __ versions */
@ -310,23 +338,324 @@ struct kprobe __kprobes *get_kprobe(void *addr)
if (p->addr == addr)
return p;
}
return NULL;
}
static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
/* Return true if the kprobe is an aggregator */
static inline int kprobe_aggrprobe(struct kprobe *p)
{
return p->pre_handler == aggr_pre_handler;
}
/*
* Keep all fields in the kprobe consistent
*/
static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
{
memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
}
#ifdef CONFIG_OPTPROBES
/*
* Call all pre_handler on the list, but ignores its return value.
* This must be called from arch-dep optimized caller.
*/
void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
set_kprobe_instance(kp);
kp->pre_handler(kp, regs);
}
reset_kprobe_instance();
}
}
/* Return true(!0) if the kprobe is ready for optimization. */
static inline int kprobe_optready(struct kprobe *p)
{
struct optimized_kprobe *op;
if (kprobe_aggrprobe(p)) {
op = container_of(p, struct optimized_kprobe, kp);
return arch_prepared_optinsn(&op->optinsn);
}
return 0;
}
/*
* Return an optimized kprobe whose optimizing code replaces
* instructions including addr (exclude breakpoint).
*/
struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
{
int i;
struct kprobe *p = NULL;
struct optimized_kprobe *op;
/* Don't check i == 0, since that is a breakpoint case. */
for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
p = get_kprobe((void *)(addr - i));
if (p && kprobe_optready(p)) {
op = container_of(p, struct optimized_kprobe, kp);
if (arch_within_optimized_kprobe(op, addr))
return p;
}
return NULL;
}
/* Optimization staging list, protected by kprobe_mutex */
static LIST_HEAD(optimizing_list);
static void kprobe_optimizer(struct work_struct *work);
static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
#define OPTIMIZE_DELAY 5
/* Kprobe jump optimizer */
static __kprobes void kprobe_optimizer(struct work_struct *work)
{
struct optimized_kprobe *op, *tmp;
/* Lock modules while optimizing kprobes */
mutex_lock(&module_mutex);
mutex_lock(&kprobe_mutex);
if (kprobes_all_disarmed)
goto end;
/*
* Wait for quiesence period to ensure all running interrupts
* are done. Because optprobe may modify multiple instructions
* there is a chance that Nth instruction is interrupted. In that
* case, running interrupt can return to 2nd-Nth byte of jump
* instruction. This wait is for avoiding it.
*/
synchronize_sched();
/*
* The optimization/unoptimization refers online_cpus via
* stop_machine() and cpu-hotplug modifies online_cpus.
* And same time, text_mutex will be held in cpu-hotplug and here.
* This combination can cause a deadlock (cpu-hotplug try to lock
* text_mutex but stop_machine can not be done because online_cpus
* has been changed)
* To avoid this deadlock, we need to call get_online_cpus()
* for preventing cpu-hotplug outside of text_mutex locking.
*/
get_online_cpus();
mutex_lock(&text_mutex);
list_for_each_entry_safe(op, tmp, &optimizing_list, list) {
WARN_ON(kprobe_disabled(&op->kp));
if (arch_optimize_kprobe(op) < 0)
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
list_del_init(&op->list);
}
mutex_unlock(&text_mutex);
put_online_cpus();
end:
mutex_unlock(&kprobe_mutex);
mutex_unlock(&module_mutex);
}
/* Optimize kprobe if p is ready to be optimized */
static __kprobes void optimize_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
/* Check if the kprobe is disabled or not ready for optimization. */
if (!kprobe_optready(p) ||
(kprobe_disabled(p) || kprobes_all_disarmed))
return;
/* Both of break_handler and post_handler are not supported. */
if (p->break_handler || p->post_handler)
return;
op = container_of(p, struct optimized_kprobe, kp);
/* Check there is no other kprobes at the optimized instructions */
if (arch_check_optimized_kprobe(op) < 0)
return;
/* Check if it is already optimized. */
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
return;
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
list_add(&op->list, &optimizing_list);
if (!delayed_work_pending(&optimizing_work))
schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
}
/* Unoptimize a kprobe if p is optimized */
static __kprobes void unoptimize_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
if ((p->flags & KPROBE_FLAG_OPTIMIZED) && kprobe_aggrprobe(p)) {
op = container_of(p, struct optimized_kprobe, kp);
if (!list_empty(&op->list))
/* Dequeue from the optimization queue */
list_del_init(&op->list);
else
/* Replace jump with break */
arch_unoptimize_kprobe(op);
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
}
}
/* Remove optimized instructions */
static void __kprobes kill_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
if (!list_empty(&op->list)) {
/* Dequeue from the optimization queue */
list_del_init(&op->list);
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
}
/* Don't unoptimize, because the target code will be freed. */
arch_remove_optimized_kprobe(op);
}
/* Try to prepare optimized instructions */
static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
arch_prepare_optimized_kprobe(op);
}
/* Free optimized instructions and optimized_kprobe */
static __kprobes void free_aggr_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
arch_remove_optimized_kprobe(op);
kfree(op);
}
/* Allocate new optimized_kprobe and try to prepare optimized instructions */
static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
if (!op)
return NULL;
INIT_LIST_HEAD(&op->list);
op->kp.addr = p->addr;
arch_prepare_optimized_kprobe(op);
return &op->kp;
}
static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
/*
* Prepare an optimized_kprobe and optimize it
* NOTE: p must be a normal registered kprobe
*/
static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
{
struct kprobe *ap;
struct optimized_kprobe *op;
ap = alloc_aggr_kprobe(p);
if (!ap)
return;
op = container_of(ap, struct optimized_kprobe, kp);
if (!arch_prepared_optinsn(&op->optinsn)) {
/* If failed to setup optimizing, fallback to kprobe */
free_aggr_kprobe(ap);
return;
}
init_aggr_kprobe(ap, p);
optimize_kprobe(ap);
}
static void __kprobes __arm_kprobe(struct kprobe *p)
{
struct kprobe *old_p;
/* Check collision with other optimized kprobes */
old_p = get_optimized_kprobe((unsigned long)p->addr);
if (unlikely(old_p))
unoptimize_kprobe(old_p); /* Fallback to unoptimized kprobe */
arch_arm_kprobe(p);
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
}
static void __kprobes __disarm_kprobe(struct kprobe *p)
{
struct kprobe *old_p;
unoptimize_kprobe(p); /* Try to unoptimize */
arch_disarm_kprobe(p);
/* If another kprobe was blocked, optimize it. */
old_p = get_optimized_kprobe((unsigned long)p->addr);
if (unlikely(old_p))
optimize_kprobe(old_p);
}
#else /* !CONFIG_OPTPROBES */
#define optimize_kprobe(p) do {} while (0)
#define unoptimize_kprobe(p) do {} while (0)
#define kill_optimized_kprobe(p) do {} while (0)
#define prepare_optimized_kprobe(p) do {} while (0)
#define try_to_optimize_kprobe(p) do {} while (0)
#define __arm_kprobe(p) arch_arm_kprobe(p)
#define __disarm_kprobe(p) arch_disarm_kprobe(p)
static __kprobes void free_aggr_kprobe(struct kprobe *p)
{
kfree(p);
}
static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
}
#endif /* CONFIG_OPTPROBES */
/* Arm a kprobe with text_mutex */
static void __kprobes arm_kprobe(struct kprobe *kp)
{
/*
* Here, since __arm_kprobe() doesn't use stop_machine(),
* this doesn't cause deadlock on text_mutex. So, we don't
* need get_online_cpus().
*/
mutex_lock(&text_mutex);
arch_arm_kprobe(kp);
__arm_kprobe(kp);
mutex_unlock(&text_mutex);
}
/* Disarm a kprobe with text_mutex */
static void __kprobes disarm_kprobe(struct kprobe *kp)
{
get_online_cpus(); /* For avoiding text_mutex deadlock */
mutex_lock(&text_mutex);
arch_disarm_kprobe(kp);
__disarm_kprobe(kp);
mutex_unlock(&text_mutex);
put_online_cpus();
}
/*
@ -395,7 +724,7 @@ static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
{
struct kprobe *kp;
if (p->pre_handler != aggr_pre_handler) {
if (!kprobe_aggrprobe(p)) {
p->nmissed++;
} else {
list_for_each_entry_rcu(kp, &p->list, list)
@ -518,15 +847,6 @@ static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
free_rp_inst(rp);
}
/*
* Keep all fields in the kprobe consistent
*/
static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
{
memcpy(&p->opcode, &old_p->opcode, sizeof(kprobe_opcode_t));
memcpy(&p->ainsn, &old_p->ainsn, sizeof(struct arch_specific_insn));
}
/*
* Add the new probe to ap->list. Fail if this is the
* second jprobe at the address - two jprobes can't coexist
@ -534,6 +854,10 @@ static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
{
BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
if (p->break_handler || p->post_handler)
unoptimize_kprobe(ap); /* Fall back to normal kprobe */
if (p->break_handler) {
if (ap->break_handler)
return -EEXIST;
@ -548,7 +872,7 @@ static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
ap->flags &= ~KPROBE_FLAG_DISABLED;
if (!kprobes_all_disarmed)
/* Arm the breakpoint again. */
arm_kprobe(ap);
__arm_kprobe(ap);
}
return 0;
}
@ -557,12 +881,13 @@ static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
* Fill in the required fields of the "manager kprobe". Replace the
* earlier kprobe in the hlist with the manager kprobe
*/
static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
{
/* Copy p's insn slot to ap */
copy_kprobe(p, ap);
flush_insn_slot(ap);
ap->addr = p->addr;
ap->flags = p->flags;
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
ap->pre_handler = aggr_pre_handler;
ap->fault_handler = aggr_fault_handler;
/* We don't care the kprobe which has gone. */
@ -572,8 +897,9 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
ap->break_handler = aggr_break_handler;
INIT_LIST_HEAD(&ap->list);
list_add_rcu(&p->list, &ap->list);
INIT_HLIST_NODE(&ap->hlist);
list_add_rcu(&p->list, &ap->list);
hlist_replace_rcu(&p->hlist, &ap->hlist);
}
@ -587,12 +913,12 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
int ret = 0;
struct kprobe *ap = old_p;
if (old_p->pre_handler != aggr_pre_handler) {
/* If old_p is not an aggr_probe, create new aggr_kprobe. */
ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
if (!kprobe_aggrprobe(old_p)) {
/* If old_p is not an aggr_kprobe, create new aggr_kprobe. */
ap = alloc_aggr_kprobe(old_p);
if (!ap)
return -ENOMEM;
add_aggr_kprobe(ap, old_p);
init_aggr_kprobe(ap, old_p);
}
if (kprobe_gone(ap)) {
@ -611,6 +937,9 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
*/
return ret;
/* Prepare optimized instructions if possible. */
prepare_optimized_kprobe(ap);
/*
* Clear gone flag to prevent allocating new slot again, and
* set disabled flag because it is not armed yet.
@ -619,6 +948,7 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
| KPROBE_FLAG_DISABLED;
}
/* Copy ap's insn slot to p */
copy_kprobe(ap, p);
return add_new_kprobe(ap, p);
}
@ -769,27 +1099,34 @@ int __kprobes register_kprobe(struct kprobe *p)
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
mutex_lock(&kprobe_mutex);
get_online_cpus(); /* For avoiding text_mutex deadlock. */
mutex_lock(&text_mutex);
old_p = get_kprobe(p->addr);
if (old_p) {
/* Since this may unoptimize old_p, locking text_mutex. */
ret = register_aggr_kprobe(old_p, p);
goto out;
}
mutex_lock(&text_mutex);
ret = arch_prepare_kprobe(p);
if (ret)
goto out_unlock_text;
goto out;
INIT_HLIST_NODE(&p->hlist);
hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
if (!kprobes_all_disarmed && !kprobe_disabled(p))
arch_arm_kprobe(p);
__arm_kprobe(p);
/* Try to optimize kprobe */
try_to_optimize_kprobe(p);
out_unlock_text:
mutex_unlock(&text_mutex);
out:
mutex_unlock(&text_mutex);
put_online_cpus();
mutex_unlock(&kprobe_mutex);
if (probed_mod)
@ -811,7 +1148,7 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
return -EINVAL;
if (old_p == p ||
(old_p->pre_handler == aggr_pre_handler &&
(kprobe_aggrprobe(old_p) &&
list_is_singular(&old_p->list))) {
/*
* Only probe on the hash list. Disarm only if kprobes are
@ -819,7 +1156,7 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
* already have been removed. We save on flushing icache.
*/
if (!kprobes_all_disarmed && !kprobe_disabled(old_p))
disarm_kprobe(p);
disarm_kprobe(old_p);
hlist_del_rcu(&old_p->hlist);
} else {
if (p->break_handler && !kprobe_gone(p))
@ -835,8 +1172,13 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
list_del_rcu(&p->list);
if (!kprobe_disabled(old_p)) {
try_to_disable_aggr_kprobe(old_p);
if (!kprobes_all_disarmed && kprobe_disabled(old_p))
if (!kprobes_all_disarmed) {
if (kprobe_disabled(old_p))
disarm_kprobe(old_p);
else
/* Try to optimize this probe again */
optimize_kprobe(old_p);
}
}
}
return 0;
@ -853,7 +1195,7 @@ static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
old_p = list_entry(p->list.next, struct kprobe, list);
list_del(&p->list);
arch_remove_kprobe(old_p);
kfree(old_p);
free_aggr_kprobe(old_p);
}
}
@ -1149,7 +1491,7 @@ static void __kprobes kill_kprobe(struct kprobe *p)
struct kprobe *kp;
p->flags |= KPROBE_FLAG_GONE;
if (p->pre_handler == aggr_pre_handler) {
if (kprobe_aggrprobe(p)) {
/*
* If this is an aggr_kprobe, we have to list all the
* chained probes and mark them GONE.
@ -1158,6 +1500,7 @@ static void __kprobes kill_kprobe(struct kprobe *p)
kp->flags |= KPROBE_FLAG_GONE;
p->post_handler = NULL;
p->break_handler = NULL;
kill_optimized_kprobe(p);
}
/*
* Here, we can remove insn_slot safely, because no thread calls
@ -1267,6 +1610,11 @@ static int __init init_kprobes(void)
}
}
#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
/* Init kprobe_optinsn_slots */
kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
#endif
/* By default, kprobes are armed */
kprobes_all_disarmed = false;
@ -1285,7 +1633,7 @@ static int __init init_kprobes(void)
#ifdef CONFIG_DEBUG_FS
static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
const char *sym, int offset,char *modname)
const char *sym, int offset, char *modname, struct kprobe *pp)
{
char *kprobe_type;
@ -1295,19 +1643,21 @@ static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
kprobe_type = "j";
else
kprobe_type = "k";
if (sym)
seq_printf(pi, "%p %s %s+0x%x %s %s%s\n",
seq_printf(pi, "%p %s %s+0x%x %s ",
p->addr, kprobe_type, sym, offset,
(modname ? modname : " "),
(kprobe_gone(p) ? "[GONE]" : ""),
((kprobe_disabled(p) && !kprobe_gone(p)) ?
"[DISABLED]" : ""));
(modname ? modname : " "));
else
seq_printf(pi, "%p %s %p %s%s\n",
p->addr, kprobe_type, p->addr,
seq_printf(pi, "%p %s %p ",
p->addr, kprobe_type, p->addr);
if (!pp)
pp = p;
seq_printf(pi, "%s%s%s\n",
(kprobe_gone(p) ? "[GONE]" : ""),
((kprobe_disabled(p) && !kprobe_gone(p)) ?
"[DISABLED]" : ""));
((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
}
static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
@ -1343,11 +1693,11 @@ static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
hlist_for_each_entry_rcu(p, node, head, hlist) {
sym = kallsyms_lookup((unsigned long)p->addr, NULL,
&offset, &modname, namebuf);
if (p->pre_handler == aggr_pre_handler) {
if (kprobe_aggrprobe(p)) {
list_for_each_entry_rcu(kp, &p->list, list)
report_probe(pi, kp, sym, offset, modname);
report_probe(pi, kp, sym, offset, modname, p);
} else
report_probe(pi, p, sym, offset, modname);
report_probe(pi, p, sym, offset, modname, NULL);
}
preempt_enable();
return 0;
@ -1425,12 +1775,13 @@ int __kprobes enable_kprobe(struct kprobe *kp)
goto out;
}
if (!kprobes_all_disarmed && kprobe_disabled(p))
arm_kprobe(p);
p->flags &= ~KPROBE_FLAG_DISABLED;
if (p != kp)
kp->flags &= ~KPROBE_FLAG_DISABLED;
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
p->flags &= ~KPROBE_FLAG_DISABLED;
arm_kprobe(p);
}
out:
mutex_unlock(&kprobe_mutex);
return ret;
@ -1450,12 +1801,13 @@ static void __kprobes arm_all_kprobes(void)
if (!kprobes_all_disarmed)
goto already_enabled;
/* Arming kprobes doesn't optimize kprobe itself */
mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
if (!kprobe_disabled(p))
arch_arm_kprobe(p);
__arm_kprobe(p);
}
mutex_unlock(&text_mutex);
@ -1482,16 +1834,23 @@ static void __kprobes disarm_all_kprobes(void)
kprobes_all_disarmed = true;
printk(KERN_INFO "Kprobes globally disabled\n");
/*
* Here we call get_online_cpus() for avoiding text_mutex deadlock,
* because disarming may also unoptimize kprobes.
*/
get_online_cpus();
mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist) {
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
arch_disarm_kprobe(p);
__disarm_kprobe(p);
}
}
mutex_unlock(&text_mutex);
put_online_cpus();
mutex_unlock(&kprobe_mutex);
/* Allow all currently running kprobes to complete */
synchronize_sched();