[PATCH net 0/5] mptcp: More v5.13 fixes

[PATCH net 0/5] mptcp: More v5.13 fixes

[Mat Martineau]

Here's another batch of MPTCP fixes for v5.13.

Patch 1 cleans up memory accounting between the MPTCP-level socket and
the subflows to more reliably transfer forward allocated memory under
pressure.

Patch 2 wakes up socket readers more reliably.

Patch 3 changes a WARN_ONCE to a pr_debug.

Patch 4 changes the selftests to only use syncookies in test cases where
they do not cause spurious failures.

Patch 5 modifies socket error reporting to avoid a possible soft lockup.


Paolo Abeni (5):
  mptcp: try harder to borrow memory from subflow under pressure
  mptcp: wake-up readers only for in sequence data
  mptcp: do not warn on bad input from the network
  selftests: mptcp: enable syncookie only in absence of reorders
  mptcp: fix soft lookup in subflow_error_report()

 net/mptcp/protocol.c                          |  52 +++++----
 net/mptcp/protocol.h                          |   1 -
 net/mptcp/subflow.c                           | 108 +++++++++---------
 .../selftests/net/mptcp/mptcp_connect.sh      |  11 +-
 4 files changed, 88 insertions(+), 84 deletions(-)


base-commit: 22488e45501eca74653b502b194eb0eb25d2ad00
-- 
2.32.0

[PATCH net 1/5] mptcp: try harder to borrow memory from subflow under pressure

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

If the host is under sever memory pressure, and RX forward
memory allocation for the msk fails, we try to borrow the
required memory from the ingress subflow.

The current attempt is a bit flaky: if skb->truesize is less
than SK_MEM_QUANTUM, the ssk will not release any memory, and
the next schedule will fail again.

Instead, directly move the required amount of pages from the
ssk to the msk, if available

Fixes: 9c3f94e1681b ("mptcp: add missing memory scheduling in the rx path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/protocol.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 5edc686faff1..534cf500521d 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -280,11 +280,13 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk,
 
 	/* try to fetch required memory from subflow */
 	if (!sk_rmem_schedule(sk, skb, skb->truesize)) {
-		if (ssk->sk_forward_alloc < skb->truesize)
-			goto drop;
-		__sk_mem_reclaim(ssk, skb->truesize);
-		if (!sk_rmem_schedule(sk, skb, skb->truesize))
+		int amount = sk_mem_pages(skb->truesize) << SK_MEM_QUANTUM_SHIFT;
+
+		if (ssk->sk_forward_alloc < amount)
 			goto drop;
+
+		ssk->sk_forward_alloc -= amount;
+		sk->sk_forward_alloc += amount;
 	}
 
 	/* the skb map_seq accounts for the skb offset:
-- 
2.32.0

[PATCH net 2/5] mptcp: wake-up readers only for in sequence data

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

Currently we rely on the subflow->data_avail field, which is subject to
races:

	ssk1
		skb len = 500 DSS(seq=1, len=1000, off=0)
		# data_avail == MPTCP_SUBFLOW_DATA_AVAIL

	ssk2
		skb len = 500 DSS(seq = 501, len=1000)
		# data_avail == MPTCP_SUBFLOW_DATA_AVAIL

	ssk1
		skb len = 500 DSS(seq = 1, len=1000, off =500)
		# still data_avail == MPTCP_SUBFLOW_DATA_AVAIL,
		# as the skb is covered by a pre-existing map,
		# which was in-sequence at reception time.

Instead we can explicitly check if some has been received in-sequence,
propagating the info from __mptcp_move_skbs_from_subflow().

Additionally add the 'ONCE' annotation to the 'data_avail' memory
access, as msk will read it outside the subflow socket lock.

Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/protocol.c | 33 ++++++++++++---------------------
 net/mptcp/protocol.h |  1 -
 net/mptcp/subflow.c  | 23 +++++++++--------------
 3 files changed, 21 insertions(+), 36 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 534cf500521d..f6e62a6dc9fb 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -670,15 +670,13 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
 /* In most cases we will be able to lock the mptcp socket.  If its already
  * owned, we need to defer to the work queue to avoid ABBA deadlock.
  */
-static void move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
+static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
 {
 	struct sock *sk = (struct sock *)msk;
 	unsigned int moved = 0;
 
 	if (inet_sk_state_load(sk) == TCP_CLOSE)
-		return;
-
-	mptcp_data_lock(sk);
+		return false;
 
 	__mptcp_move_skbs_from_subflow(msk, ssk, &moved);
 	__mptcp_ofo_queue(msk);
@@ -690,7 +688,7 @@ static void move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
 	 */
 	if (mptcp_pending_data_fin(sk, NULL))
 		mptcp_schedule_work(sk);
-	mptcp_data_unlock(sk);
+	return moved > 0;
 }
 
 void mptcp_data_ready(struct sock *sk, struct sock *ssk)
@@ -698,7 +696,6 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk)
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	int sk_rbuf, ssk_rbuf;
-	bool wake;
 
 	/* The peer can send data while we are shutting down this
 	 * subflow at msk destruction time, but we must avoid enqueuing
@@ -707,28 +704,22 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk)
 	if (unlikely(subflow->disposable))
 		return;
 
-	/* move_skbs_to_msk below can legitly clear the data_avail flag,
-	 * but we will need later to properly woke the reader, cache its
-	 * value
-	 */
-	wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL;
-	if (wake)
-		set_bit(MPTCP_DATA_READY, &msk->flags);
-
 	ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf);
 	sk_rbuf = READ_ONCE(sk->sk_rcvbuf);
 	if (unlikely(ssk_rbuf > sk_rbuf))
 		sk_rbuf = ssk_rbuf;
 
-	/* over limit? can't append more skbs to msk */
+	/* over limit? can't append more skbs to msk, Also, no need to wake-up*/
 	if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf)
-		goto wake;
-
-	move_skbs_to_msk(msk, ssk);
+		return;
 
-wake:
-	if (wake)
+	/* Wake-up the reader only for in-sequence data */
+	mptcp_data_lock(sk);
+	if (move_skbs_to_msk(msk, ssk)) {
+		set_bit(MPTCP_DATA_READY, &msk->flags);
 		sk->sk_data_ready(sk);
+	}
+	mptcp_data_unlock(sk);
 }
 
 static bool mptcp_do_flush_join_list(struct mptcp_sock *msk)
@@ -860,7 +851,7 @@ static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk)
 	sock_owned_by_me(sk);
 
 	mptcp_for_each_subflow(msk, subflow) {
-		if (subflow->data_avail)
+		if (READ_ONCE(subflow->data_avail))
 			return mptcp_subflow_tcp_sock(subflow);
 	}
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 0c6f99c67345..385796f0ef19 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -362,7 +362,6 @@ mptcp_subflow_rsk(const struct request_sock *rsk)
 enum mptcp_data_avail {
 	MPTCP_SUBFLOW_NODATA,
 	MPTCP_SUBFLOW_DATA_AVAIL,
-	MPTCP_SUBFLOW_OOO_DATA
 };
 
 struct mptcp_delegated_action {
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ef3d037f984a..ebb898acd65a 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1000,7 +1000,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
 	struct sk_buff *skb;
 
 	if (!skb_peek(&ssk->sk_receive_queue))
-		subflow->data_avail = 0;
+		WRITE_ONCE(subflow->data_avail, 0);
 	if (subflow->data_avail)
 		return true;
 
@@ -1039,18 +1039,13 @@ static bool subflow_check_data_avail(struct sock *ssk)
 		ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
 		pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
 			 ack_seq);
-		if (ack_seq == old_ack) {
-			subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
-			break;
-		} else if (after64(ack_seq, old_ack)) {
-			subflow->data_avail = MPTCP_SUBFLOW_OOO_DATA;
-			break;
+		if (unlikely(before64(ack_seq, old_ack))) {
+			mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
+			continue;
 		}
 
-		/* only accept in-sequence mapping. Old values are spurious
-		 * retransmission
-		 */
-		mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
+		WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_DATA_AVAIL);
+		break;
 	}
 	return true;
 
@@ -1070,7 +1065,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
 		subflow->reset_transient = 0;
 		subflow->reset_reason = MPTCP_RST_EMPTCP;
 		tcp_send_active_reset(ssk, GFP_ATOMIC);
-		subflow->data_avail = 0;
+		WRITE_ONCE(subflow->data_avail, 0);
 		return false;
 	}
 
@@ -1080,7 +1075,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
 	subflow->map_seq = READ_ONCE(msk->ack_seq);
 	subflow->map_data_len = skb->len;
 	subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
-	subflow->data_avail = MPTCP_SUBFLOW_DATA_AVAIL;
+	WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_DATA_AVAIL);
 	return true;
 }
 
@@ -1092,7 +1087,7 @@ bool mptcp_subflow_data_available(struct sock *sk)
 	if (subflow->map_valid &&
 	    mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
 		subflow->map_valid = 0;
-		subflow->data_avail = 0;
+		WRITE_ONCE(subflow->data_avail, 0);
 
 		pr_debug("Done with mapping: seq=%u data_len=%u",
 			 subflow->map_subflow_seq,
-- 
2.32.0

[PATCH net 3/5] mptcp: do not warn on bad input from the network

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

warn_bad_map() produces a kernel WARN on bad input coming
from the network. Use pr_debug() to avoid spamming the system
log.

Additionally, when the right bound check fails, warn_bad_map() reports
the wrong ssn value, let's fix it.

Fixes: 648ef4b88673 ("mptcp: Implement MPTCP receive path")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/107
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/subflow.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ebb898acd65a..e05e05ec9687 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -784,10 +784,10 @@ static u64 expand_seq(u64 old_seq, u16 old_data_len, u64 seq)
 	return seq | ((old_seq + old_data_len + 1) & GENMASK_ULL(63, 32));
 }
 
-static void warn_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
+static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
 {
-	WARN_ONCE(1, "Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
-		  ssn, subflow->map_subflow_seq, subflow->map_data_len);
+	pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
+		 ssn, subflow->map_subflow_seq, subflow->map_data_len);
 }
 
 static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
@@ -812,13 +812,13 @@ static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
 		/* Mapping covers data later in the subflow stream,
 		 * currently unsupported.
 		 */
-		warn_bad_map(subflow, ssn);
+		dbg_bad_map(subflow, ssn);
 		return false;
 	}
 	if (unlikely(!before(ssn, subflow->map_subflow_seq +
 				  subflow->map_data_len))) {
 		/* Mapping does covers past subflow data, invalid */
-		warn_bad_map(subflow, ssn + skb->len);
+		dbg_bad_map(subflow, ssn);
 		return false;
 	}
 	return true;
-- 
2.32.0

[PATCH net 4/5] selftests: mptcp: enable syncookie only in absence of reorders

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

Syncookie validation may fail for OoO packets, causing spurious
resets and self-tests failures, so let's force syncookie only
for tests iteration with no OoO.

Fixes: fed61c4b584c ("selftests: mptcp: make 2nd net namespace use tcp syn cookies unconditionally")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/198
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 tools/testing/selftests/net/mptcp/mptcp_connect.sh | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.sh b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
index 9ca5f1ba461e..2b495dc8d78e 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
@@ -197,9 +197,6 @@ ip -net "$ns4" link set ns4eth3 up
 ip -net "$ns4" route add default via 10.0.3.2
 ip -net "$ns4" route add default via dead:beef:3::2
 
-# use TCP syn cookies, even if no flooding was detected.
-ip netns exec "$ns2" sysctl -q net.ipv4.tcp_syncookies=2
-
 set_ethtool_flags() {
 	local ns="$1"
 	local dev="$2"
@@ -737,6 +734,14 @@ for sender in $ns1 $ns2 $ns3 $ns4;do
 		exit $ret
 	fi
 
+	# ns1<->ns2 is not subject to reordering/tc delays. Use it to test
+	# mptcp syncookie support.
+	if [ $sender = $ns1 ]; then
+		ip netns exec "$ns2" sysctl -q net.ipv4.tcp_syncookies=2
+	else
+		ip netns exec "$ns2" sysctl -q net.ipv4.tcp_syncookies=1
+	fi
+
 	run_tests "$ns2" $sender 10.0.1.2
 	run_tests "$ns2" $sender dead:beef:1::2
 	run_tests "$ns2" $sender 10.0.2.1
-- 
2.32.0

[PATCH net 5/5] mptcp: fix soft lookup in subflow_error_report()

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

Maxim reported a soft lookup in subflow_error_report():

 watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0]
 RIP: 0010:native_queued_spin_lock_slowpath
 RSP: 0018:ffffa859c0003bc0 EFLAGS: 00000202
 RAX: 0000000000000101 RBX: 0000000000000001 RCX: 0000000000000000
 RDX: ffff9195c2772d88 RSI: 0000000000000000 RDI: ffff9195c2772d88
 RBP: ffff9195c2772d00 R08: 00000000000067b0 R09: c6e31da9eb1e44f4
 R10: ffff9195ef379700 R11: ffff9195edb50710 R12: ffff9195c2772d88
 R13: ffff9195f500e3d0 R14: ffff9195ef379700 R15: ffff9195ef379700
 FS:  0000000000000000(0000) GS:ffff91961f400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 000000c000407000 CR3: 0000000002988000 CR4: 00000000000006f0
 Call Trace:
  <IRQ>
 _raw_spin_lock_bh
 subflow_error_report
 mptcp_subflow_data_available
 __mptcp_move_skbs_from_subflow
 mptcp_data_ready
 tcp_data_queue
 tcp_rcv_established
 tcp_v4_do_rcv
 tcp_v4_rcv
 ip_protocol_deliver_rcu
 ip_local_deliver_finish
 __netif_receive_skb_one_core
 netif_receive_skb
 rtl8139_poll 8139too
 __napi_poll
 net_rx_action
 __do_softirq
 __irq_exit_rcu
 common_interrupt
  </IRQ>

The calling function - mptcp_subflow_data_available() - can be invoked
from different contexts:
- plain ssk socket lock
- ssk socket lock + mptcp_data_lock
- ssk socket lock + mptcp_data_lock + msk socket lock.

Since subflow_error_report() tries to acquire the mptcp_data_lock, the
latter two call chains will cause soft lookup.

This change addresses the issue moving the error reporting call to
outer functions, where the held locks list is known and the we can
acquire only the needed one.

Reported-by: Maxim Galaganov <max@internet.ru>
Fixes: 15cc10453398 ("mptcp: deliver ssk errors to msk")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/199
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/protocol.c |  9 ++++++
 net/mptcp/subflow.c  | 75 +++++++++++++++++++++++---------------------
 2 files changed, 48 insertions(+), 36 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f6e62a6dc9fb..632350018fb6 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -680,6 +680,12 @@ static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk)
 
 	__mptcp_move_skbs_from_subflow(msk, ssk, &moved);
 	__mptcp_ofo_queue(msk);
+	if (unlikely(ssk->sk_err)) {
+		if (!sock_owned_by_user(sk))
+			__mptcp_error_report(sk);
+		else
+			set_bit(MPTCP_ERROR_REPORT,  &msk->flags);
+	}
 
 	/* If the moves have caught up with the DATA_FIN sequence number
 	 * it's time to ack the DATA_FIN and change socket state, but
@@ -1948,6 +1954,9 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk)
 		done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
 		mptcp_data_unlock(sk);
 		tcp_cleanup_rbuf(ssk, moved);
+
+		if (unlikely(ssk->sk_err))
+			__mptcp_error_report(sk);
 		unlock_sock_fast(ssk, slowpath);
 	} while (!done);
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index e05e05ec9687..be1de4084196 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1060,7 +1060,6 @@ static bool subflow_check_data_avail(struct sock *ssk)
 		 * subflow_error_report() will introduce the appropriate barriers
 		 */
 		ssk->sk_err = EBADMSG;
-		ssk->sk_error_report(ssk);
 		tcp_set_state(ssk, TCP_CLOSE);
 		subflow->reset_transient = 0;
 		subflow->reset_reason = MPTCP_RST_EMPTCP;
@@ -1115,41 +1114,6 @@ void mptcp_space(const struct sock *ssk, int *space, int *full_space)
 	*full_space = tcp_full_space(sk);
 }
 
-static void subflow_data_ready(struct sock *sk)
-{
-	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
-	u16 state = 1 << inet_sk_state_load(sk);
-	struct sock *parent = subflow->conn;
-	struct mptcp_sock *msk;
-
-	msk = mptcp_sk(parent);
-	if (state & TCPF_LISTEN) {
-		/* MPJ subflow are removed from accept queue before reaching here,
-		 * avoid stray wakeups
-		 */
-		if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
-			return;
-
-		set_bit(MPTCP_DATA_READY, &msk->flags);
-		parent->sk_data_ready(parent);
-		return;
-	}
-
-	WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
-		     !subflow->mp_join && !(state & TCPF_CLOSE));
-
-	if (mptcp_subflow_data_available(sk))
-		mptcp_data_ready(parent, sk);
-}
-
-static void subflow_write_space(struct sock *ssk)
-{
-	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
-
-	mptcp_propagate_sndbuf(sk, ssk);
-	mptcp_write_space(sk);
-}
-
 void __mptcp_error_report(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow;
@@ -1190,6 +1154,43 @@ static void subflow_error_report(struct sock *ssk)
 	mptcp_data_unlock(sk);
 }
 
+static void subflow_data_ready(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	u16 state = 1 << inet_sk_state_load(sk);
+	struct sock *parent = subflow->conn;
+	struct mptcp_sock *msk;
+
+	msk = mptcp_sk(parent);
+	if (state & TCPF_LISTEN) {
+		/* MPJ subflow are removed from accept queue before reaching here,
+		 * avoid stray wakeups
+		 */
+		if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
+			return;
+
+		set_bit(MPTCP_DATA_READY, &msk->flags);
+		parent->sk_data_ready(parent);
+		return;
+	}
+
+	WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
+		     !subflow->mp_join && !(state & TCPF_CLOSE));
+
+	if (mptcp_subflow_data_available(sk))
+		mptcp_data_ready(parent, sk);
+	else if (unlikely(sk->sk_err))
+		subflow_error_report(sk);
+}
+
+static void subflow_write_space(struct sock *ssk)
+{
+	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
+
+	mptcp_propagate_sndbuf(sk, ssk);
+	mptcp_write_space(sk);
+}
+
 static struct inet_connection_sock_af_ops *
 subflow_default_af_ops(struct sock *sk)
 {
@@ -1500,6 +1501,8 @@ static void subflow_state_change(struct sock *sk)
 	 */
 	if (mptcp_subflow_data_available(sk))
 		mptcp_data_ready(parent, sk);
+	else if (unlikely(sk->sk_err))
+		subflow_error_report(sk);
 
 	subflow_sched_work_if_closed(mptcp_sk(parent), sk);
 
-- 
2.32.0

Re: [PATCH net 0/5] mptcp: More v5.13 fixes

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (refs/heads/master):

On Thu, 10 Jun 2021 15:59:39 -0700 you wrote:
> Here's another batch of MPTCP fixes for v5.13.
> 
> Patch 1 cleans up memory accounting between the MPTCP-level socket and
> the subflows to more reliably transfer forward allocated memory under
> pressure.
> 
> Patch 2 wakes up socket readers more reliably.
> 
> [...]

Here is the summary with links:
  - [net,1/5] mptcp: try harder to borrow memory from subflow under pressure
    https://git.kernel.org/netdev/net/c/72f961320d5d
  - [net,2/5] mptcp: wake-up readers only for in sequence data
    https://git.kernel.org/netdev/net/c/99d1055ce246
  - [net,3/5] mptcp: do not warn on bad input from the network
    https://git.kernel.org/netdev/net/c/61e710227e97
  - [net,4/5] selftests: mptcp: enable syncookie only in absence of reorders
    https://git.kernel.org/netdev/net/c/2395da0e1793
  - [net,5/5] mptcp: fix soft lookup in subflow_error_report()
    https://git.kernel.org/netdev/net/c/499ada507336

You are awesome, thank you!
--
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