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-rw-r--r--include/asm-i386/kprobes.h1
-rw-r--r--include/asm-ia64/kprobes.h1
-rw-r--r--include/asm-powerpc/kprobes.h2
-rw-r--r--include/asm-sparc64/kprobes.h1
-rw-r--r--include/asm-x86_64/kprobes.h1
-rw-r--r--kernel/kprobes.c30
6 files changed, 29 insertions, 7 deletions
diff --git a/include/asm-i386/kprobes.h b/include/asm-i386/kprobes.h
index 57d157c5cf89..0730a20f6db8 100644
--- a/include/asm-i386/kprobes.h
+++ b/include/asm-i386/kprobes.h
@@ -44,6 +44,7 @@ typedef u8 kprobe_opcode_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
+#define ARCH_INACTIVE_KPROBE_COUNT 0
void arch_remove_kprobe(struct kprobe *p);
void kretprobe_trampoline(void);
diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
index 8c0fc227f0fb..2418a787c405 100644
--- a/include/asm-ia64/kprobes.h
+++ b/include/asm-ia64/kprobes.h
@@ -82,6 +82,7 @@ struct kprobe_ctlblk {
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
+#define ARCH_INACTIVE_KPROBE_COUNT 1
#define SLOT0_OPCODE_SHIFT (37)
#define SLOT1_p1_OPCODE_SHIFT (37 - (64-46))
diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h
index f466bc804f41..2d0af52c823d 100644
--- a/include/asm-powerpc/kprobes.h
+++ b/include/asm-powerpc/kprobes.h
@@ -50,6 +50,8 @@ typedef unsigned int kprobe_opcode_t;
IS_TWI(instr) || IS_TDI(instr))
#define ARCH_SUPPORTS_KRETPROBES
+#define ARCH_INACTIVE_KPROBE_COUNT 1
+
void kretprobe_trampoline(void);
extern void arch_remove_kprobe(struct kprobe *p);
diff --git a/include/asm-sparc64/kprobes.h b/include/asm-sparc64/kprobes.h
index e9bb26f770ed..15065af566c2 100644
--- a/include/asm-sparc64/kprobes.h
+++ b/include/asm-sparc64/kprobes.h
@@ -12,6 +12,7 @@ typedef u32 kprobe_opcode_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define arch_remove_kprobe(p) do {} while (0)
+#define ARCH_INACTIVE_KPROBE_COUNT 0
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
diff --git a/include/asm-x86_64/kprobes.h b/include/asm-x86_64/kprobes.h
index 98a1e95ddb98..d36febd9bb18 100644
--- a/include/asm-x86_64/kprobes.h
+++ b/include/asm-x86_64/kprobes.h
@@ -43,6 +43,7 @@ typedef u8 kprobe_opcode_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
+#define ARCH_INACTIVE_KPROBE_COUNT 1
void kretprobe_trampoline(void);
extern void arch_remove_kprobe(struct kprobe *p);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 507f26e7ae7c..64aab081153b 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -47,11 +47,17 @@
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
+static atomic_t kprobe_count;
DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
+static struct notifier_block kprobe_page_fault_nb = {
+ .notifier_call = kprobe_exceptions_notify,
+ .priority = 0x7fffffff /* we need to notified first */
+};
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe->ainsn.insn points to the copy of the instruction to be
@@ -465,6 +471,8 @@ static int __kprobes __register_kprobe(struct kprobe *p,
old_p = get_kprobe(p->addr);
if (old_p) {
ret = register_aggr_kprobe(old_p, p);
+ if (!ret)
+ atomic_inc(&kprobe_count);
goto out;
}
@@ -475,6 +483,10 @@ static int __kprobes __register_kprobe(struct kprobe *p,
hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
+ if (atomic_add_return(1, &kprobe_count) == \
+ (ARCH_INACTIVE_KPROBE_COUNT + 1))
+ register_page_fault_notifier(&kprobe_page_fault_nb);
+
arch_arm_kprobe(p);
out:
@@ -553,6 +565,16 @@ valid_p:
}
mutex_unlock(&kprobe_mutex);
}
+
+ /* Call unregister_page_fault_notifier()
+ * if no probes are active
+ */
+ mutex_lock(&kprobe_mutex);
+ if (atomic_add_return(-1, &kprobe_count) == \
+ ARCH_INACTIVE_KPROBE_COUNT)
+ unregister_page_fault_notifier(&kprobe_page_fault_nb);
+ mutex_unlock(&kprobe_mutex);
+ return;
}
static struct notifier_block kprobe_exceptions_nb = {
@@ -560,10 +582,6 @@ static struct notifier_block kprobe_exceptions_nb = {
.priority = 0x7fffffff /* we need to be notified first */
};
-static struct notifier_block kprobe_page_fault_nb = {
- .notifier_call = kprobe_exceptions_notify,
- .priority = 0x7fffffff /* we need to notified first */
-};
int __kprobes register_jprobe(struct jprobe *jp)
{
@@ -673,14 +691,12 @@ static int __init init_kprobes(void)
INIT_HLIST_HEAD(&kprobe_table[i]);
INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
}
+ atomic_set(&kprobe_count, 0);
err = arch_init_kprobes();
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
- if (!err)
- err = register_page_fault_notifier(&kprobe_page_fault_nb);
-
return err;
}