The patch below does not apply to the 5.11-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 417789df4a03bc820b082bcc503f0d4c5e4704b9 Mon Sep 17 00:00:00 2001 From: Paolo Abeni <pabeni@xxxxxxxxxx> Date: Thu, 4 Mar 2021 13:32:15 -0800 Subject: [PATCH] mptcp: fix missing wakeup __mptcp_clean_una() can free write memory and should wake-up user-space processes when needed. When such function is invoked by the MPTCP receive path, the wakeup is not needed, as the TCP stack will later trigger subflow_write_space which will do the wakeup as needed. Other __mptcp_clean_una() call sites need an additional wakeup check Let's bundle the relevant code in a new helper and use it. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/165 Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") Fixes: 64b9cea7a0af ("mptcp: fix spurious retransmissions") Tested-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d2a2169e6d9e..76958570ae7f 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1061,6 +1061,12 @@ static void __mptcp_clean_una(struct sock *sk) } } +static void __mptcp_clean_una_wakeup(struct sock *sk) +{ + __mptcp_clean_una(sk); + mptcp_write_space(sk); +} + static void mptcp_enter_memory_pressure(struct sock *sk) { struct mptcp_subflow_context *subflow; @@ -2270,7 +2276,7 @@ static void __mptcp_retrans(struct sock *sk) struct sock *ssk; int ret; - __mptcp_clean_una(sk); + __mptcp_clean_una_wakeup(sk); dfrag = mptcp_rtx_head(sk); if (!dfrag) return; @@ -2983,7 +2989,7 @@ static void mptcp_release_cb(struct sock *sk) } if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) - __mptcp_clean_una(sk); + __mptcp_clean_una_wakeup(sk); if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags)) __mptcp_error_report(sk);
