mptcp: close race between scheduler and state change

The mptcp scheduler may race with subflow sockets state change: data
transmission on the selected socket may fail and a later release could
try to use mss_now reset to 0 for a divide operation.

Address the issue by explicitly checking for the critical scenario.

Fixes: c886d70286 ("mptcp: do not queue data on closed subflows")
Cc: stable@vger.kernel.org
Reported-by: Shardul Bankar <shardul.b@mpiricsoftware.com>
Reported-by: Xinyang Ge <xinyang@anthropic.com>
Closes: https://lore.kernel.org/20260525194828.1137119-1-shardul.b@mpiricsoftware.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-2-0cf5c72667c8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Paolo Abeni 2026-09-17 15:05:58 +02:00 committed by Jakub Kicinski
parent 2b0f561f21
commit 42064de57f

View File

@ -1664,7 +1664,9 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk)
static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info)
{
tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal);
if (info->mss_now)
tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle,
info->size_goal);
release_sock(ssk);
}