Commit c92bf26c authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Paolo Abeni
Browse files

rtnl: allocate more attr tables on the heap 



Commit a2939745 ("rtnetlink: avoid frame size warning in rtnl_newlink()")
moved to allocating the largest attribute array of rtnl_newlink()
on the heap. Kalle reports the stack has grown above 1k again:

  net/core/rtnetlink.c:3557:1: error: the frame size of 1104 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Move more attrs to the heap, wrap them in a struct.
Don't bother with linkinfo, it's referenced a lot and we take
its size so it's awkward to move, plus it's small (6 elements).

Reported-by: default avatarKalle Valo <kvalo@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Tested-by: default avatarKalle Valo <kvalo@kernel.org>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent d7ab15ab

net/core/rtnetlink.c

+18 −12
Original line number Diff line number Diff line
@@ -3302,17 +3302,23 @@ static int rtnl_group_changelink(const struct sk_buff *skb, 
	return 0;

}



struct rtnl_newlink_tbs {

	struct nlattr *tb[IFLA_MAX + 1];

	struct nlattr *attr[RTNL_MAX_TYPE + 1];

	struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1];

};



static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			  struct nlattr **attr, struct netlink_ext_ack *extack)

			  struct rtnl_newlink_tbs *tbs,

			  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];

	struct nlattr ** const tb = tbs->tb;

	const struct rtnl_link_ops *m_ops;

	struct net_device *master_dev;

	struct net *net = sock_net(skb->sk);

	const struct rtnl_link_ops *ops;

	struct nlattr *tb[IFLA_MAX + 1];

	struct net *dest_net, *link_net;

	struct nlattr **slave_data;

	char kind[MODULE_NAME_LEN];
@@ -3382,12 +3388,12 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
			return -EINVAL;



		if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {

			err = nla_parse_nested_deprecated(attr, ops->maxtype,

			err = nla_parse_nested_deprecated(tbs->attr, ops->maxtype,

							  linkinfo[IFLA_INFO_DATA],

							  ops->policy, extack);

			if (err < 0)

				return err;

			data = attr;

			data = tbs->attr;

		}

		if (ops->validate) {

			err = ops->validate(tb, data, extack);
@@ -3403,14 +3409,14 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 


		if (m_ops->slave_maxtype &&

		    linkinfo[IFLA_INFO_SLAVE_DATA]) {

			err = nla_parse_nested_deprecated(slave_attr,

			err = nla_parse_nested_deprecated(tbs->slave_attr,

							  m_ops->slave_maxtype,

							  linkinfo[IFLA_INFO_SLAVE_DATA],

							  m_ops->slave_policy,

							  extack);

			if (err < 0)

				return err;

			slave_data = slave_attr;

			slave_data = tbs->slave_attr;

		}

	}
@@ -3559,15 +3565,15 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, 
static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,

			struct netlink_ext_ack *extack)

{

	struct nlattr **attr;

	struct rtnl_newlink_tbs *tbs;

	int ret;



	attr = kmalloc_array(RTNL_MAX_TYPE + 1, sizeof(*attr), GFP_KERNEL);

	if (!attr)

	tbs = kmalloc(sizeof(*tbs), GFP_KERNEL);

	if (!tbs)

		return -ENOMEM;



	ret = __rtnl_newlink(skb, nlh, attr, extack);

	kfree(attr);

	ret = __rtnl_newlink(skb, nlh, tbs, extack);

	kfree(tbs);

	return ret;

}