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rtnetlink: avoid frame size warning in rtnl_newlink()

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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>
This commit is contained in:
Jakub Kicinski 2018-11-27 22:32:31 -08:00 committed by David S. Miller
parent 420d031822
commit a293974590
1 changed files with 17 additions and 3 deletions
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20
net/core/rtnetlink.c
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@ -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)
{