The smc_poll code tries to finish connect() if the socket is in state SMC_INIT and polling of the internal CLC-socket returns with EPOLLOUT. This makes sense for a select/poll call following a connect call, but not without preceding connect(). With this patch smc_poll starts connect logic only, if the CLC-socket is no longer in its initial state TCP_CLOSE. In addition, a poll error on the internal CLC-socket is always propagated to the SMC socket. With this patch the code path mentioned by syzbot https://syzkaller.appspot.com/bug?extid=03faa2dc16b8b64be396 is no longer possible. Signed-off-by: Ursula Braun <ubraun@xxxxxxxxxxxxx> Reported-by: syzbot+03faa2dc16b8b64be396@xxxxxxxxxxxxxxxxxxxxxxxxx --- net/smc/af_smc.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 4470501374bf..8b4c059bd13b 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -1166,13 +1166,15 @@ static __poll_t smc_poll(struct file *file, struct socket *sock, /* delegate to CLC child sock */ release_sock(sk); mask = smc->clcsock->ops->poll(file, smc->clcsock, wait); - /* if non-blocking connect finished ... */ lock_sock(sk); - if ((sk->sk_state == SMC_INIT) && (mask & EPOLLOUT)) { - sk->sk_err = smc->clcsock->sk->sk_err; - if (sk->sk_err) { - mask |= EPOLLERR; - } else { + sk->sk_err = smc->clcsock->sk->sk_err; + if (sk->sk_err) { + mask |= EPOLLERR; + } else { + /* if non-blocking connect finished ... */ + if (sk->sk_state == SMC_INIT && + mask & EPOLLOUT && + smc->clcsock->sk->sk_state != TCP_CLOSE) { rc = smc_connect_rdma(smc); if (rc < 0) mask |= EPOLLERR; -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
