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authorNicolas Rybowski <nicolas.rybowski@tessares.net>2020-12-10 14:24:58 -0800
committerJakub Kicinski <kuba@kernel.org>2020-12-14 17:30:06 -0800
commit3764b0c5651e34ceb3e7d5c75b6fd8e7b72112ac (patch)
treede5f7156cfb07f742ef9c7c1efe9af6ee3a88f70 /net
parentefc36d3c344a36fe73cda93c55763058629e0f2c (diff)
mptcp: attach subflow socket to parent cgroup
It has been observed that the kernel sockets created for the subflows (except the first one) are not in the same cgroup as their parents. That's because the additional subflows are created by kernel workers. This is a problem with eBPF programs attached to the parent's cgroup won't be executed for the children. But also with any other features of CGroup linked to a sk. This patch fixes this behaviour. As the subflow sockets are created by the kernel, we can't use 'mem_cgroup_sk_alloc' because of the current context being the one of the kworker. This is why we have to do low level memcg manipulation, if required. Suggested-by: Matthieu Baerts <matthieu.baerts@tessares.net> Suggested-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/mptcp/subflow.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index fefcaf497938..bf808f1fabe5 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1167,6 +1167,30 @@ failed:
return err;
}
+static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
+{
+#ifdef CONFIG_SOCK_CGROUP_DATA
+ struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data,
+ *child_skcd = &child->sk_cgrp_data;
+
+ /* only the additional subflows created by kworkers have to be modified */
+ if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
+ cgroup_id(sock_cgroup_ptr(child_skcd))) {
+#ifdef CONFIG_MEMCG
+ struct mem_cgroup *memcg = parent->sk_memcg;
+
+ mem_cgroup_sk_free(child);
+ if (memcg && css_tryget(&memcg->css))
+ child->sk_memcg = memcg;
+#endif /* CONFIG_MEMCG */
+
+ cgroup_sk_free(child_skcd);
+ *child_skcd = *parent_skcd;
+ cgroup_sk_clone(child_skcd);
+ }
+#endif /* CONFIG_SOCK_CGROUP_DATA */
+}
+
int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
{
struct mptcp_subflow_context *subflow;
@@ -1187,6 +1211,9 @@ int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
lock_sock(sf->sk);
+ /* the newly created socket has to be in the same cgroup as its parent */
+ mptcp_attach_cgroup(sk, sf->sk);
+
/* kernel sockets do not by default acquire net ref, but TCP timer
* needs it.
*/