From: Ursula Braun ubraun@linux.ibm.com
commit 67f562e3e147750a02b2a91d21a163fc44a1d13e upstream.
SMC does not work together with FASTOPEN. If sendmsg() is called with flag MSG_FASTOPEN in SMC_INIT state, the SMC-socket switches to fallback mode. To handle the previous ioctl FIOASYNC call correctly in this case, it is necessary to transfer the socket wait queue fasync_list to the internal TCP socket.
Reported-by: syzbot+4b1fe8105f8044a26162@syzkaller.appspotmail.com Fixes: ee9dfbef02d18 ("net/smc: handle sockopts forcing fallback") Signed-off-by: Ursula Braun ubraun@linux.ibm.com Signed-off-by: Karsten Graul kgraul@linux.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/smc/af_smc.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -470,6 +470,8 @@ static void smc_switch_to_fallback(struc if (smc->sk.sk_socket && smc->sk.sk_socket->file) { smc->clcsock->file = smc->sk.sk_socket->file; smc->clcsock->file->private_data = smc->clcsock; + smc->clcsock->wq.fasync_list = + smc->sk.sk_socket->wq.fasync_list; } }