The patch below does not apply to the 5.15-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@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 0a567c2a10033bf04ed618368d179bce6977984b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024080738-providing-expiring-91d1@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

0a567c2a1003 ("mptcp: fix bad RCVPRUNED mib accounting") 6511882cdd82 ("mptcp: allocate fwd memory separately on the rx and tx path") 765ff425528f ("mptcp: use lockdep_assert_held_once() instead of open-coding it")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0a567c2a10033bf04ed618368d179bce6977984b Mon Sep 17 00:00:00 2001 From: Paolo Abeni pabeni@redhat.com Date: Wed, 31 Jul 2024 12:10:14 +0200 Subject: [PATCH] mptcp: fix bad RCVPRUNED mib accounting

Since its introduction, the mentioned MIB accounted for the wrong event: wake-up being skipped as not-needed on some edge condition instead of incoming skb being dropped after landing in the (subflow) receive queue.

Move the increment in the correct location.

Fixes: ce599c516386 ("mptcp: properly account bulk freed memory") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index a2fc54ed68c0..0d536b183a6c 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -350,8 +350,10 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, skb_orphan(skb);

/* try to fetch required memory from subflow */ - if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) + if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); goto drop; + }

has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;

@@ -844,10 +846,8 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) sk_rbuf = ssk_rbuf;

/* over limit? can't append more skbs to msk, Also, no need to wake-up*/ - if (__mptcp_rmem(sk) > sk_rbuf) { - MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); + if (__mptcp_rmem(sk) > sk_rbuf) return; - }

/* Wake-up the reader only for in-sequence data */ mptcp_data_lock(sk);