From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] AF_UNIX: Fix deadlock on connecting to shutdown socket Date: Mon, 19 Oct 2009 11:57:13 +0000 Message-ID: <20091019115713.GB6869@ff.dom.local> References: <4ADC010C.5070809@hitachi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, alan@lxorguk.ukuu.org.uk, davem@davemloft.net, satoshi.oshima.fk@hitachi.com, hidehiro.kawai.ez@hitachi.com, hideo.aoki.tk@hitachi.com To: Tomoki Sekiyama Return-path: Content-Disposition: inline In-Reply-To: <4ADC010C.5070809@hitachi.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 19-10-2009 08:02, Tomoki Sekiyama wrote: ... > Why this happens: > Error checks between unix_socket_connect() and unix_wait_for_peer() are > inconsistent. The former calls the latter to wait until the backlog is > processed. Despite the latter returns without doing anything when the > socket is shutdown, the former doesn't check the shutdown state and > just retries calling the latter forever. > > Patch: > The patch below adds shutdown check into unix_socket_connect(), so > connect(2) to the shutdown socket will return -ECONREFUSED. > > Signed-off-by: Tomoki Sekiyama > Signed-off-by: Masanori Yoshida > --- > net/unix/af_unix.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index 51ab497..fc820cd 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -1074,6 +1074,8 @@ restart: > err = -ECONNREFUSED; > if (other->sk_state != TCP_LISTEN) > goto out_unlock; > + if (other->sk_shutdown & RCV_SHUTDOWN) > + goto out_unlock; Isn't the shutdown call expected to change sk_state to TCP_CLOSE? Jarek P.