kprobes: Cleanup disabling and unregistering path (6f0f1dd7) · Commits · 戴 / test

kernel/kprobes.c

+72 −56

Original line number	Original line	Diff line number	Diff line
	@@ -1039,23 +1039,6 @@ static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
	return add_new_kprobe(ap, p);		return add_new_kprobe(ap, p);
	}		}

	/* Try to disable aggr_kprobe, and return 1 if succeeded.*/
	static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
	{
	struct kprobe *kp;

	list_for_each_entry_rcu(kp, &p->list, list) {
	if (!kprobe_disabled(kp))
	/*
	* There is an active probe on the list.
	* We can't disable aggr_kprobe.
	*/
	return 0;
	}
	p->flags \|= KPROBE_FLAG_DISABLED;
	return 1;
	}

	static int __kprobes in_kprobes_functions(unsigned long addr)		static int __kprobes in_kprobes_functions(unsigned long addr)
	{		{
	struct kprobe_blackpoint *kb;		struct kprobe_blackpoint *kb;
	@@ -1228,6 +1211,47 @@ fail_with_jump_label:
	}		}
	EXPORT_SYMBOL_GPL(register_kprobe);		EXPORT_SYMBOL_GPL(register_kprobe);

			/* Check if all probes on the aggrprobe are disabled */
			static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
			{
			struct kprobe *kp;

			list_for_each_entry_rcu(kp, &ap->list, list)
			if (!kprobe_disabled(kp))
			/*
			* There is an active probe on the list.
			* We can't disable this ap.
			*/
			return 0;

			return 1;
			}

			/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
			static struct kprobe __kprobes __disable_kprobe(struct kprobe p)
			{
			struct kprobe *orig_p;

			/* Get an original kprobe for return */
			orig_p = __get_valid_kprobe(p);
			if (unlikely(orig_p == NULL))
			return NULL;

			if (!kprobe_disabled(p)) {
			/* Disable probe if it is a child probe */
			if (p != orig_p)
			p->flags \|= KPROBE_FLAG_DISABLED;

			/* Try to disarm and disable this/parent probe */
			if (p == orig_p \|\| aggr_kprobe_disabled(orig_p)) {
			disarm_kprobe(orig_p);
			orig_p->flags \|= KPROBE_FLAG_DISABLED;
			}
			}

			return orig_p;
			}

	/*		/*
	* Unregister a kprobe without a scheduler synchronization.		* Unregister a kprobe without a scheduler synchronization.
	*/		*/
	@@ -1235,22 +1259,26 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
	{		{
	struct kprobe ap, list_p;		struct kprobe ap, list_p;

	ap = __get_valid_kprobe(p);		/* Disable kprobe. This will disarm it if needed. */
			ap = __disable_kprobe(p);
	if (ap == NULL)		if (ap == NULL)
	return -EINVAL;		return -EINVAL;

	if (ap == p \|\|		if (ap == p)
	(kprobe_aggrprobe(ap) &&
	list_is_singular(&ap->list))) {
	/*		/*
	* Only probe on the hash list. Disarm only if kprobes are		* This probe is an independent(and non-optimized) kprobe
	* enabled and not gone - otherwise, the breakpoint would		* (not an aggrprobe). Remove from the hash list.
	* already have been removed. We save on flushing icache.
	*/		*/
	if (!kprobes_all_disarmed && !kprobe_disabled(ap))		goto disarmed;
	disarm_kprobe(ap);
	hlist_del_rcu(&ap->hlist);		/* Following process expects this probe is an aggrprobe */
	} else {		WARN_ON(!kprobe_aggrprobe(ap));

			if (list_is_singular(&ap->list))
			/* This probe is the last child of aggrprobe */
			goto disarmed;
			else {
			/* If disabling probe has special handlers, update aggrprobe */
	if (p->break_handler && !kprobe_gone(p))		if (p->break_handler && !kprobe_gone(p))
	ap->break_handler = NULL;		ap->break_handler = NULL;
	if (p->post_handler && !kprobe_gone(p)) {		if (p->post_handler && !kprobe_gone(p)) {
	@@ -1261,18 +1289,22 @@ static int __kprobes __unregister_kprobe_top(struct kprobe *p)
	ap->post_handler = NULL;		ap->post_handler = NULL;
	}		}
	noclean:		noclean:
			/*
			* Remove from the aggrprobe: this path will do nothing in
			* __unregister_kprobe_bottom().
			*/
	list_del_rcu(&p->list);		list_del_rcu(&p->list);
	if (!kprobe_disabled(ap)) {		if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
	try_to_disable_aggr_kprobe(ap);		/*
	if (!kprobes_all_disarmed) {		* Try to optimize this probe again, because post
	if (kprobe_disabled(ap))		* handler may have been changed.
	disarm_kprobe(ap);		*/
	else
	/* Try to optimize this probe again */
	optimize_kprobe(ap);		optimize_kprobe(ap);
	}		}
	}		return 0;
	}
			disarmed:
			hlist_del_rcu(&ap->hlist);
	return 0;		return 0;
	}		}

	@@ -1606,29 +1638,13 @@ static void __kprobes kill_kprobe(struct kprobe *p)
	int __kprobes disable_kprobe(struct kprobe *kp)		int __kprobes disable_kprobe(struct kprobe *kp)
	{		{
	int ret = 0;		int ret = 0;
	struct kprobe *p;

	mutex_lock(&kprobe_mutex);		mutex_lock(&kprobe_mutex);

	/* Check whether specified probe is valid. */		/* Disable this kprobe */
	p = __get_valid_kprobe(kp);		if (__disable_kprobe(kp) == NULL)
	if (unlikely(p == NULL)) {
	ret = -EINVAL;		ret = -EINVAL;
	goto out;
	}

	/* If the probe is already disabled (or gone), just return */
	if (kprobe_disabled(kp))
	goto out;

	kp->flags \|= KPROBE_FLAG_DISABLED;
	if (p != kp)
	/* When kp != p, p is always enabled. */
	try_to_disable_aggr_kprobe(p);

	if (!kprobes_all_disarmed && kprobe_disabled(p))
	disarm_kprobe(p);
	out:
	mutex_unlock(&kprobe_mutex);		mutex_unlock(&kprobe_mutex);
	return ret;		return ret;
	}		}

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