This is a note to let you know that I've just added the patch titled
mpls: no longer hold RTNL in mpls_netconf_dump_devconf()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mpls-no-longer-hold-rtnl-in-mpls_netconf_dump_devcon.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit aea6a2fb49a166fb5dae848c92abd7943f047393
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Apr 10 11:19:50 2024 +0000
mpls: no longer hold RTNL in mpls_netconf_dump_devconf()
[ Upstream commit e0f89d2864b062b027196925ea19f94b2ce50d6a ]
- Use for_each_netdev_dump() to no longer rely
on net->dev_index_head hash table.
- No longer care of net->dev_base_seq
- Fix return value at the end of a dump,
so that NLMSG_DONE can be appended to current skb,
saving one recvmsg() system call.
- No longer grab RTNL, RCU protection is enough,
afer adding one READ_ONCE(mdev->input_enabled)
in mpls_netconf_fill_devconf()
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240410111951.2673193-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: 5be2062e3080 ("mpls: Handle error of rtnl_register_module().")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 1af29af653885..ba034fcd59f0d 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -1154,7 +1154,7 @@ static int mpls_netconf_fill_devconf(struct sk_buff *skb, struct mpls_dev *mdev,
if ((all || type == NETCONFA_INPUT) &&
nla_put_s32(skb, NETCONFA_INPUT,
- mdev->input_enabled) < 0)
+ READ_ONCE(mdev->input_enabled)) < 0)
goto nla_put_failure;
nlmsg_end(skb, nlh);
@@ -1303,11 +1303,12 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb,
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
- struct hlist_head *head;
+ struct {
+ unsigned long ifindex;
+ } *ctx = (void *)cb->ctx;
struct net_device *dev;
struct mpls_dev *mdev;
- int idx, s_idx;
- int h, s_h;
+ int err = 0;
if (cb->strict_check) {
struct netlink_ext_ack *extack = cb->extack;
@@ -1324,40 +1325,23 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb,
}
}
- s_h = cb->args[0];
- s_idx = idx = cb->args[1];
-
- for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
- idx = 0;
- head = &net->dev_index_head[h];
- rcu_read_lock();
- cb->seq = net->dev_base_seq;
- hlist_for_each_entry_rcu(dev, head, index_hlist) {
- if (idx < s_idx)
- goto cont;
- mdev = mpls_dev_get(dev);
- if (!mdev)
- goto cont;
- if (mpls_netconf_fill_devconf(skb, mdev,
- NETLINK_CB(cb->skb).portid,
- nlh->nlmsg_seq,
- RTM_NEWNETCONF,
- NLM_F_MULTI,
- NETCONFA_ALL) < 0) {
- rcu_read_unlock();
- goto done;
- }
- nl_dump_check_consistent(cb, nlmsg_hdr(skb));
-cont:
- idx++;
- }
- rcu_read_unlock();
+ rcu_read_lock();
+ for_each_netdev_dump(net, dev, ctx->ifindex) {
+ mdev = mpls_dev_get(dev);
+ if (!mdev)
+ continue;
+ err = mpls_netconf_fill_devconf(skb, mdev,
+ NETLINK_CB(cb->skb).portid,
+ nlh->nlmsg_seq,
+ RTM_NEWNETCONF,
+ NLM_F_MULTI,
+ NETCONFA_ALL);
+ if (err < 0)
+ break;
}
-done:
- cb->args[0] = h;
- cb->args[1] = idx;
+ rcu_read_unlock();
- return skb->len;
+ return err;
}
#define MPLS_PERDEV_SYSCTL_OFFSET(field) \
@@ -2771,7 +2755,8 @@ static int __init mpls_init(void)
mpls_getroute, mpls_dump_routes, 0);
rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
mpls_netconf_get_devconf,
- mpls_netconf_dump_devconf, 0);
+ mpls_netconf_dump_devconf,
+ RTNL_FLAG_DUMP_UNLOCKED);
err = ipgre_tunnel_encap_add_mpls_ops();
if (err)
pr_err("Can't add mpls over gre tunnel ops\n");
