This is a note to let you know that I've just added the patch titled tipc: call tipc_wait_for_connect only when dlen is not 0 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: tipc-call-tipc_wait_for_connect-only-when-dlen-is-not-0.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 <stable@xxxxxxxxxxxxxxx> know about it. >From 7387a72c5f84f0dfb57618f9e4770672c0d2e4c9 Mon Sep 17 00:00:00 2001 From: Xin Long <lucien.xin@xxxxxxxxx> Date: Sun, 15 Aug 2021 03:13:36 -0400 Subject: tipc: call tipc_wait_for_connect only when dlen is not 0 From: Xin Long <lucien.xin@xxxxxxxxx> commit 7387a72c5f84f0dfb57618f9e4770672c0d2e4c9 upstream. __tipc_sendmsg() is called to send SYN packet by either tipc_sendmsg() or tipc_connect(). The difference is in tipc_connect(), it will call tipc_wait_for_connect() after __tipc_sendmsg() to wait until connecting is done. So there's no need to wait in __tipc_sendmsg() for this case. This patch is to fix it by calling tipc_wait_for_connect() only when dlen is not 0 in __tipc_sendmsg(), which means it's called by tipc_connect(). Note this also fixes the failure in tipcutils/test/ptts/: # ./tipcTS & # ./tipcTC 9 (hang) Fixes: 36239dab6da7 ("tipc: fix implicit-connect for SYN+") Reported-by: Shuang Li <shuali@xxxxxxxxxx> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx> Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tipc/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1511,7 +1511,7 @@ static int __tipc_sendmsg(struct socket if (unlikely(syn && !rc)) { tipc_set_sk_state(sk, TIPC_CONNECTING); - if (timeout) { + if (dlen && timeout) { timeout = msecs_to_jiffies(timeout); tipc_wait_for_connect(sock, &timeout); } Patches currently in stable-queue which might be from lucien.xin@xxxxxxxxx are queue-5.10/tipc-call-tipc_wait_for_connect-only-when-dlen-is-not-0.patch