rtnetlink: avoid frame size warning in rtnl_newlink() (a2939745) · Commits · 戴 / test

Standard kernel compilation produces the following warning: net/core/rtnetlink.c: In function ‘rtnl_newlink’: net/core/rtnetlink.c:3232:1: warning: the frame size of 1288 bytes is larger than 1024 bytes [-Wframe-larger-than=] } ^ This should not really be an issue, as rtnl_newlink() stack is generally quite shallow. Fix the warning by allocating attributes with kmalloc() in a wrapper and passing it down to rtnl_newlink(), avoiding complexities on error paths. Alternatively we could kmalloc() some structure within rtnl_newlink(), slave attributes look like a good candidate. In practice it adds to already rather high complexity and length of the function. Signed-off-by:

Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by:

David Ahern <dsahern@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

+17 −3

Original line number	Diff line number	Diff line
		@@ -2971,14 +2971,13 @@ static int rtnl_group_changelink(const struct sk_buff *skb,
		return 0;
		}

		static int rtnl_newlink(struct sk_buff skb, struct nlmsghdr nlh,
		struct netlink_ext_ack *extack)
		static int __rtnl_newlink(struct sk_buff skb, struct nlmsghdr nlh,
		struct nlattr *attr, struct netlink_ext_ack extack)
		{
		struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];
		unsigned char name_assign_type = NET_NAME_USER;
		struct nlattr *linkinfo[IFLA_INFO_MAX + 1];
		const struct rtnl_link_ops *m_ops = NULL;
		struct nlattr *attr[RTNL_MAX_TYPE + 1];
		struct net_device *master_dev = NULL;
		struct net *net = sock_net(skb->sk);
		const struct rtnl_link_ops *ops;
		@@ -3226,6 +3225,21 @@ out_unregister:
		goto out;
		}

		static int rtnl_newlink(struct sk_buff skb, struct nlmsghdr nlh,
		struct netlink_ext_ack *extack)
		{
		struct nlattr **attr;
		int ret;

		attr = kmalloc_array(RTNL_MAX_TYPE + 1, sizeof(*attr), GFP_KERNEL);
		if (!attr)
		return -ENOMEM;

		ret = __rtnl_newlink(skb, nlh, attr, extack);
		kfree(attr);
		return ret;
		}

		static int rtnl_getlink(struct sk_buff skb, struct nlmsghdr nlh,
		struct netlink_ext_ack *extack)
		{

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