From cef4902b0fadfc4181176ef5713f0b7cf2a40d8f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 10 Jul 2024 15:16:53 +0000 Subject: [PATCH] net: reduce rtnetlink_rcv_msg() stack usage IFLA_MAX is increasing slowly but surely. Some compilers use more than 512 bytes of stack in rtnetlink_rcv_msg() because it calls rtnl_calcit() for RTM_GETLINK message. Use noinline_for_stack attribute to not inline rtnl_calcit(), and directly use nla_for_each_attr_type() (Jakub suggestion) because we only care about IFLA_EXT_MASK at this stage. Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Link: https://patch.msgid.link/20240710151653.3786604-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index eabfc8290f5e..87e67194f240 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3969,22 +3969,28 @@ static int rtnl_dellinkprop(struct sk_buff *skb, struct nlmsghdr *nlh, return rtnl_linkprop(RTM_DELLINKPROP, skb, nlh, extack); } -static u32 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh) +static noinline_for_stack u32 rtnl_calcit(struct sk_buff *skb, + struct nlmsghdr *nlh) { struct net *net = sock_net(skb->sk); size_t min_ifinfo_dump_size = 0; - struct nlattr *tb[IFLA_MAX+1]; u32 ext_filter_mask = 0; struct net_device *dev; - int hdrlen; + struct nlattr *nla; + int hdrlen, rem; /* Same kernel<->userspace interface hack as in rtnl_dump_ifinfo. */ hdrlen = nlmsg_len(nlh) < sizeof(struct ifinfomsg) ? sizeof(struct rtgenmsg) : sizeof(struct ifinfomsg); - if (nlmsg_parse_deprecated(nlh, hdrlen, tb, IFLA_MAX, ifla_policy, NULL) >= 0) { - if (tb[IFLA_EXT_MASK]) - ext_filter_mask = nla_get_u32(tb[IFLA_EXT_MASK]); + if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) + return NLMSG_GOODSIZE; + + nla_for_each_attr_type(nla, IFLA_EXT_MASK, + nlmsg_attrdata(nlh, hdrlen), + nlmsg_attrlen(nlh, hdrlen), rem) { + if (nla_len(nla) == sizeof(u32)) + ext_filter_mask = nla_get_u32(nla); } if (!ext_filter_mask) -- 2.25.1