From: Karsten Graul <kgraul@linux.ibm.com>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org,
heiko.carstens@de.ibm.com, raspl@linux.ibm.com,
ubraun@linux.ibm.com
Subject: [PATCH net] net/smc: fix fastopen for non-blocking connect()
Date: Fri, 15 Nov 2019 12:39:30 +0100 [thread overview]
Message-ID: <20191115113930.38684-1-kgraul@linux.ibm.com> (raw)
From: Ursula Braun <ubraun@linux.ibm.com>
FASTOPEN does not work with SMC-sockets. Since SMC allows fallback to
TCP native during connection start, the FASTOPEN setsockopts trigger
this fallback, if the SMC-socket is still in state SMC_INIT.
But if a FASTOPEN setsockopt is called after a non-blocking connect(),
this is broken, and fallback does not make sense.
This change complements
commit cd2063604ea6 ("net/smc: avoid fallback in case of non-blocking connect")
and fixes the syzbot reported problem "WARNING in smc_unhash_sk".
Reported-by: syzbot+8488cc4cf1c9e09b8b86@syzkaller.appspotmail.com
Fixes: e1bbdd570474 ("net/smc: reduce sock_put() for fallback sockets")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
net/smc/af_smc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8edf1619f0e4..737b49909a7a 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1732,7 +1732,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
case TCP_FASTOPEN_KEY:
case TCP_FASTOPEN_NO_COOKIE:
/* option not supported by SMC */
- if (sk->sk_state == SMC_INIT) {
+ if (sk->sk_state == SMC_INIT && !smc->connect_nonblock) {
smc_switch_to_fallback(smc);
smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
} else {
--
2.17.1
next reply other threads:[~2019-11-15 11:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 11:39 Karsten Graul [this message]
2019-11-16 21:04 ` [PATCH net] net/smc: fix fastopen for non-blocking connect() David Miller
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