6.12-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
commit 449e6912a2522af672e99992e1201a454910864e upstream.
If the recvmsg() blocks after receiving some data - i.e. due to SO_RCVLOWAT - the MPTCP code will attempt multiple times to adjust the receive buffer size, wrongly accounting every time the cumulative of received data - instead of accounting only for the delta.
Address the issue moving mptcp_rcv_space_adjust just after the data reception and passing it only the just received bytes.
This also removes an unneeded difference between the TCP and MPTCP RX code path implementation.
Fixes: 581302298524 ("mptcp: error out earlier on disconnect") 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 Link: https://patch.msgid.link/20241230-net-mptcp-rbuf-fixes-v1-1-8608af434ceb@ker... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/protocol.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1939,6 +1939,8 @@ do_error: goto out; }
+static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied); + static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, struct msghdr *msg, size_t len, int flags, @@ -1992,6 +1994,7 @@ static int __mptcp_recvmsg_mskq(struct m break; }
+ mptcp_rcv_space_adjust(msk, copied); return copied; }
@@ -2268,7 +2271,6 @@ static int mptcp_recvmsg(struct sock *sk }
pr_debug("block timeout %ld\n", timeo); - mptcp_rcv_space_adjust(msk, copied); err = sk_wait_data(sk, &timeo, NULL); if (err < 0) { err = copied ? : err; @@ -2276,8 +2278,6 @@ static int mptcp_recvmsg(struct sock *sk } }
- mptcp_rcv_space_adjust(msk, copied); - out_err: if (cmsg_flags && copied >= 0) { if (cmsg_flags & MPTCP_CMSG_TS)