From: Zijian Zhang <zijianzhang@xxxxxxxxxxxxx>
When we do sk_psock_verdict_apply->sk_psock_skb_ingress, an sk_msg will
be created out of the skb, and the rmem accounting of the sk_msg will be
handled by the skb.
For skmsgs in __SK_REDIRECT case of tcp_bpf_send_verdict, when redirecting
to the ingress of a socket, although we sk_rmem_schedule and add sk_msg to
the ingress_msg of sk_redir, we do not update sk_rmem_alloc. As a result,
except for the global memory limit, the rmem of sk_redir is nearly
unlimited. Thus, add sk_rmem_alloc related logic to limit the recv buffer.
Since the function sk_msg_recvmsg and __sk_psock_purge_ingress_msg are
used in these two paths. We use "msg->skb" to test whether the sk_msg is
skb backed up. If it's not, we shall do the memory accounting explicitly.
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Zijian Zhang <zijianzhang@xxxxxxxxxxxxx>
---
include/linux/skmsg.h | 11 ++++++++---
net/core/skmsg.c | 6 +++++-
net/ipv4/tcp_bpf.c | 4 +++-
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index d9b03e0746e7..2cbe0c22a32f 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -317,17 +317,22 @@ static inline void sock_drop(struct sock *sk, struct sk_buff *skb)
kfree_skb(skb);
}
-static inline void sk_psock_queue_msg(struct sk_psock *psock,
+static inline bool sk_psock_queue_msg(struct sk_psock *psock,
struct sk_msg *msg)
{
+ bool ret;
+
spin_lock_bh(&psock->ingress_lock);
- if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
+ if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
list_add_tail(&msg->list, &psock->ingress_msg);
- else {
+ ret = true;
+ } else {
sk_msg_free(psock->sk, msg);
kfree(msg);
+ ret = false;
}
spin_unlock_bh(&psock->ingress_lock);
+ return ret;
}
static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index e90fbab703b2..8ad7e6755fd6 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -445,8 +445,10 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
if (likely(!peek)) {
sge->offset += copy;
sge->length -= copy;
- if (!msg_rx->skb)
+ if (!msg_rx->skb) {
sk_mem_uncharge(sk, copy);
+ atomic_sub(copy, &sk->sk_rmem_alloc);
+ }
msg_rx->sg.size -= copy;
if (!sge->length) {
@@ -772,6 +774,8 @@ static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
list_del(&msg->list);
+ if (!msg->skb)
+ atomic_sub(msg->sg.size, &psock->sk->sk_rmem_alloc);
sk_msg_free(psock->sk, msg);
kfree(msg);
}
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index b21ea634909c..392678ae80f4 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -56,6 +56,7 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
}
sk_mem_charge(sk, size);
+ atomic_add(size, &sk->sk_rmem_alloc);
sk_msg_xfer(tmp, msg, i, size);
copied += size;
if (sge->length)
@@ -74,7 +75,8 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
if (!ret) {
msg->sg.start = i;
- sk_psock_queue_msg(psock, tmp);
+ if (!sk_psock_queue_msg(psock, tmp))
+ atomic_sub(copied, &sk->sk_rmem_alloc);
sk_psock_data_ready(sk, psock);
} else {
sk_msg_free(sk, tmp);
--
2.20.1
