This is a note to let you know that I've just added the patch titled
mptcp: fix data race around msk->first access
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mptcp-fix-data-race-around-msk-first-access.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0545614d0c7d286546c0bc5eca67615845d493d3
Author: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Wed May 31 12:37:06 2023 -0700
mptcp: fix data race around msk->first access
[ Upstream commit 1b1b43ee7a208096ecd79e626f2fc90d4a321111 ]
The first subflow socket is accessed outside the msk socket lock
by mptcp_subflow_fail(), we need to annotate each write access
with WRITE_ONCE, but a few spots still lacks it.
Fixes: 76a13b315709 ("mptcp: invoke MP_FAIL response when needed")
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 8d0c03091c409..64d4910e337ea 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -102,7 +102,7 @@ static int __mptcp_socket_create(struct mptcp_sock *msk)
if (err)
return err;
- msk->first = ssock->sk;
+ WRITE_ONCE(msk->first, ssock->sk);
WRITE_ONCE(msk->subflow, ssock);
subflow = mptcp_subflow_ctx(ssock->sk);
list_add(&subflow->node, &msk->conn_list);
@@ -2391,7 +2391,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
sock_put(ssk);
if (ssk == msk->first)
- msk->first = NULL;
+ WRITE_ONCE(msk->first, NULL);
out:
if (ssk == msk->last_snd)
@@ -2692,7 +2692,7 @@ static int __mptcp_init_sock(struct sock *sk)
WRITE_ONCE(msk->rmem_released, 0);
msk->timer_ival = TCP_RTO_MIN;
- msk->first = NULL;
+ WRITE_ONCE(msk->first, NULL);
inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss;
WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk)));
WRITE_ONCE(msk->allow_infinite_fallback, true);
