FAILED: patch "[PATCH] mptcp: ensure snd_una is properly initialized on connect" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-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 <[email protected]>.

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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024061719-prewashed-wimp-a695@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

8031b58c3a9b ("mptcp: ensure snd_una is properly initialized on connect") fb7a0d334894 ("mptcp: ensure snd_nxt is properly initialized on connect") 54f1944ed6d2 ("mptcp: factor out mptcp_connect()")
a42cf9d18278 ("mptcp: poll allow write call before actual connect") d98a82a6afc7 ("mptcp: handle defer connect in mptcp_sendmsg") 3e5014909b56 ("mptcp: cleanup MPJ subflow list handling") 3d1d6d66e156 ("mptcp: implement support for user-space disconnect") b29fcfb54cd7 ("mptcp: full disconnect implementation") 3ce0852c86b9 ("mptcp: enforce HoL-blocking estimation") 7cd2802d7496 ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")

thanks,

greg k-h

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

From 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <[email protected]>
Date: Fri, 7 Jun 2024 17:01:48 +0200
Subject: [PATCH] mptcp: ensure snd_una is properly initialized on connect

This is strictly related to commit fb7a0d334894 ("mptcp: ensure snd_nxt is properly initialized on connect"). It turns out that syzkaller can trigger the retransmit after fallback and before processing any other incoming packet - so that snd_una is still left uninitialized.

Address the issue explicitly initializing snd_una together with snd_nxt and write_seq.

index 96b113854bd3..bb7dca8aa2d9 100644
@@ -3740,6 +3740,7 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 
 	WRITE_ONCE(msk->write_seq, subflow->idsn);
 	WRITE_ONCE(msk->snd_nxt, subflow->idsn);
+	WRITE_ONCE(msk->snd_una, subflow->idsn);
 	if (likely(!__mptcp_check_fallback(msk)))
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE);
 

From: Paolo Abeni <[email protected]>

commit 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 upstream.

This is strictly related to commit fb7a0d334894 ("mptcp: ensure snd_nxt is properly initialized on connect"). It turns out that syzkaller can trigger the retransmit after fallback and before processing any other incoming packet - so that snd_una is still left uninitialized.

Address the issue explicitly initializing snd_una together with snd_nxt and write_seq.

[ Conflicts in protocol.c, similar to the ones from commit 99951b62bf20
("mptcp: ensure snd_nxt is properly initialized on connect"), with the same resolution. Note that in this version, 'snd_una' is an atomic64 type, so use atomic64_set() instead, as it is done everywhere else. ]

---
 net/mptcp/protocol.c | 1 +
 1 file changed, 1 insertion(+)

index 36fa456f42ba..a36493bbf895 100644
@@ -2646,6 +2646,7 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 		mptcp_subflow_early_fallback(msk, subflow);
 
 	WRITE_ONCE(msk->write_seq, subflow->idsn);
+	atomic64_set(&msk->snd_una, msk->write_seq);
 
 do_connect:
 	err = ssock->ops->connect(ssock, uaddr, addr_len, flags);

2.43.0

This is a note to let you know that I've just added the patch titled

mptcp: ensure snd_una is properly initialized on connect

to the 5.10-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-ensure-snd_una-is-properly-initialized-on-connect.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Tue Jun 18 14:25:14 2024
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 18 Jun 2024 14:24:45 +0200
Subject: mptcp: ensure snd_una is properly initialized on connect
To: [email protected], [email protected]
Cc: MPTCP Upstream <[email protected]>, Paolo Abeni <[email protected]>, Mat Martineau <[email protected]>, Christoph Paasch <[email protected]>, Matthieu Baerts <[email protected]>, Jakub Kicinski <[email protected]>
Message-ID: <[email protected]>

From: Paolo Abeni <[email protected]>

commit 8031b58c3a9b1db3ef68b3bd749fbee2e1e1aaa3 upstream.

This is strictly related to commit fb7a0d334894 ("mptcp: ensure snd_nxt is properly initialized on connect"). It turns out that syzkaller can trigger the retransmit after fallback and before processing any other incoming packet - so that snd_una is still left uninitialized.

Address the issue explicitly initializing snd_una together with snd_nxt and write_seq.

[ Conflicts in protocol.c, similar to the ones from commit 99951b62bf20
("mptcp: ensure snd_nxt is properly initialized on connect"), with the same resolution. Note that in this version, 'snd_una' is an atomic64 type, so use atomic64_set() instead, as it is done everywhere else. ]

---
 net/mptcp/protocol.c |    1 +
 1 file changed, 1 insertion(+)

@@ -2646,6 +2646,7 @@ static int mptcp_stream_connect(struct s
 		mptcp_subflow_early_fallback(msk, subflow);
 
 	WRITE_ONCE(msk->write_seq, subflow->idsn);
+	atomic64_set(&msk->snd_una, msk->write_seq);
 
 do_connect:
 	err = ssock->ops->connect(ssock, uaddr, addr_len, flags);

Patches currently in stable-queue which might be from [email protected] are

queue-5.10/mptcp-pm-inc-rmaddr-mib-counter-once-per-rm_addr-id.patch queue-5.10/mptcp-ensure-snd_una-is-properly-initialized-on-connect.patch queue-5.10/mptcp-pm-update-add_addr-counters-after-connect.patch

All backports now queued up, thanks.

greg k-h