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Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c91
1 files changed, 43 insertions, 48 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3897630d2335..f14ccd35e9b6 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -48,7 +48,7 @@
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
-static DEFINE_SPINLOCK(kprobe_lock); /* Protects kprobe_table */
+static DECLARE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
@@ -167,7 +167,7 @@ static inline void reset_kprobe_instance(void)
/*
* This routine is called either:
- * - under the kprobe_lock spinlock - during kprobe_[un]register()
+ * - under the kprobe_mutex - during kprobe_[un]register()
* OR
* - with preemption disabled - from arch/xxx/kernel/kprobes.c
*/
@@ -420,7 +420,6 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
/*
* This is the second or subsequent kprobe at the address - handle
* the intricacies
- * TODO: Move kcalloc outside the spin_lock
*/
static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
struct kprobe *p)
@@ -442,25 +441,6 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
return ret;
}
-/* kprobe removal house-keeping routines */
-static inline void cleanup_kprobe(struct kprobe *p, unsigned long flags)
-{
- arch_disarm_kprobe(p);
- hlist_del_rcu(&p->hlist);
- spin_unlock_irqrestore(&kprobe_lock, flags);
- arch_remove_kprobe(p);
-}
-
-static inline void cleanup_aggr_kprobe(struct kprobe *old_p,
- struct kprobe *p, unsigned long flags)
-{
- list_del_rcu(&p->list);
- if (list_empty(&old_p->list))
- cleanup_kprobe(old_p, flags);
- else
- spin_unlock_irqrestore(&kprobe_lock, flags);
-}
-
static int __kprobes in_kprobes_functions(unsigned long addr)
{
if (addr >= (unsigned long)__kprobes_text_start
@@ -472,7 +452,6 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
int __kprobes register_kprobe(struct kprobe *p)
{
int ret = 0;
- unsigned long flags = 0;
struct kprobe *old_p;
struct module *mod;
@@ -484,18 +463,17 @@ int __kprobes register_kprobe(struct kprobe *p)
(unlikely(!try_module_get(mod))))
return -EINVAL;
- if ((ret = arch_prepare_kprobe(p)) != 0)
- goto rm_kprobe;
-
p->nmissed = 0;
- spin_lock_irqsave(&kprobe_lock, flags);
+ down(&kprobe_mutex);
old_p = get_kprobe(p->addr);
if (old_p) {
ret = register_aggr_kprobe(old_p, p);
goto out;
}
- arch_copy_kprobe(p);
+ if ((ret = arch_prepare_kprobe(p)) != 0)
+ goto out;
+
INIT_HLIST_NODE(&p->hlist);
hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
@@ -503,10 +481,8 @@ int __kprobes register_kprobe(struct kprobe *p)
arch_arm_kprobe(p);
out:
- spin_unlock_irqrestore(&kprobe_lock, flags);
-rm_kprobe:
- if (ret == -EEXIST)
- arch_remove_kprobe(p);
+ up(&kprobe_mutex);
+
if (ret && mod)
module_put(mod);
return ret;
@@ -514,29 +490,48 @@ rm_kprobe:
void __kprobes unregister_kprobe(struct kprobe *p)
{
- unsigned long flags;
- struct kprobe *old_p;
struct module *mod;
+ struct kprobe *old_p, *cleanup_p;
- spin_lock_irqsave(&kprobe_lock, flags);
+ down(&kprobe_mutex);
old_p = get_kprobe(p->addr);
- if (old_p) {
- /* cleanup_*_kprobe() does the spin_unlock_irqrestore */
- if (old_p->pre_handler == aggr_pre_handler)
- cleanup_aggr_kprobe(old_p, p, flags);
- else
- cleanup_kprobe(p, flags);
+ if (unlikely(!old_p)) {
+ up(&kprobe_mutex);
+ return;
+ }
- synchronize_sched();
+ if ((old_p->pre_handler == aggr_pre_handler) &&
+ (p->list.next == &old_p->list) &&
+ (p->list.prev == &old_p->list)) {
+ /* Only one element in the aggregate list */
+ arch_disarm_kprobe(p);
+ hlist_del_rcu(&old_p->hlist);
+ cleanup_p = old_p;
+ } else if (old_p == p) {
+ /* Only one kprobe element in the hash list */
+ arch_disarm_kprobe(p);
+ hlist_del_rcu(&p->hlist);
+ cleanup_p = p;
+ } else {
+ list_del_rcu(&p->list);
+ cleanup_p = NULL;
+ }
- if ((mod = module_text_address((unsigned long)p->addr)))
- module_put(mod);
+ up(&kprobe_mutex);
- if (old_p->pre_handler == aggr_pre_handler &&
- list_empty(&old_p->list))
+ synchronize_sched();
+ if ((mod = module_text_address((unsigned long)p->addr)))
+ module_put(mod);
+
+ if (cleanup_p) {
+ if (cleanup_p->pre_handler == aggr_pre_handler) {
+ list_del_rcu(&p->list);
kfree(old_p);
- } else
- spin_unlock_irqrestore(&kprobe_lock, flags);
+ }
+ down(&kprobe_mutex);
+ arch_remove_kprobe(p);
+ up(&kprobe_mutex);
+ }
}
static struct notifier_block kprobe_exceptions_nb = {