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[82.53.135.154]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499aa0fda98sm70253085e9.1.2026.08.19.01.54.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Aug 2026 01:54:42 -0700 (PDT) Date: Wed, 19 Aug 2026 10:54:38 +0200 From: Stefano Garzarella To: Michal Luczaj Cc: Hyunwoo Kim , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, leonardi@redhat.com, bobbyeshleman@meta.com, stefanha@redhat.com, mst@redhat.com, virtualization@lists.linux.dev, netdev@vger.kernel.org Subject: Re: [PATCH net] vsock: do not reset a socket in connect() once it has connected Message-ID: References: <218226a4-38e6-4a16-a660-6c1bb92f9f96@rbox.co> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: IRAKQA0Hzs551YrR3tjvPMx3GjD95TpGF4rPZQT39IQ_1787129684 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline On Mon, Aug 17, 2026 at 12:29:11AM +0200, Michal Luczaj wrote: >On 8/14/26 03:45, Hyunwoo Kim wrote: >> On Thu, Aug 13, 2026 at 11:42:17AM +0200, Michal Luczaj wrote: >>> On 8/12/26 22:13, Hyunwoo Kim wrote: >>>> commit 002541ef650b ("vsock: Ignore signal/timeout on connect() if >>>> already established") stopped connect() from resetting an established >>>> socket. The check only looks at whether sk_state is TCP_ESTABLISHED at >>>> that moment, and the state can change while connect() sleeps. >>> >>> I guess this makes my fix incomplete. "Fixes: 002541ef650b"? >> >> It is incomplete, yes. But this has been triggerable since d021c344051a, so >> I'd keep Fixes: d021c344051a. > >OK, I get it. > >>>> A peer RST moves the socket to TCP_CLOSING, and it is not removed from >>>> vsock_connected_table on that path. connect() then wakes up, fails the >>>> check, and resets a socket that had actually connected to TCP_CLOSE and >>>> SS_UNCONNECTED. >>> >>> Thanks for the details. Do I get it right: connect() misses the fact that >>> socket might have already transitioned TCP_ESTABLISHED -> TCP_CLOSING >>> during schedule_timeout()? >> >> Yes, that's it. >> >>> >>> How about: >>> >>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c >>> index 622dbd046799..39c42ef016c3 100644 >>> --- a/net/vmw_vsock/af_vsock.c >>> +++ b/net/vmw_vsock/af_vsock.c >>> @@ -1807,15 +1807,18 @@ static int vsock_connect(struct socket *sock, struct sockaddr_unsized *addr, >>> timeout = schedule_timeout(timeout); >>> lock_sock(sk); >>> >>> - /* Connection established. Whatever happens to socket once we >>> + /* Connection (has been) established. Whatever happens to socket once we >>> * release it, that's not connect()'s concern. No need to go >>> * into signal and timeout handling. Call it a day. >>> * >>> * Note that allowing to "reset" an already established socket >>> * here is racy and insecure. >>> */ >>> - if (sk->sk_state == TCP_ESTABLISHED) >>> - break; >>> + if (sk->sk_state == TCP_ESTABLISHED || >>> + sk->sk_state == TCP_CLOSING) { >>> + err = -sk->sk_err; >>> + goto out_wait; >>> + } >>> >>> /* If connection was _not_ established and a signal/timeout came >>> * to be, we want the socket's state reset. User space may want >>> >>> ? >> >> Yes, I like it better than mine. I confirmed it fixes the issue. > >Great, thanks. > >> If you don't mind, would you take the patch from here? > >Sure, no problem. > >Stefano, does this look good to you? Yep, thanks for helping here! My only doubt is if it makes sense to leave the `break` there, and add a similar check before resetting the socket, I mean something like this: err = sock_error(sk); if (err && sk->sk_state != TCP_ESTABLISHED && sk->sk_state != TCP_CLOSING)) { sk->sk_state = TCP_CLOSE; sock->state = SS_UNCONNECTED; } Just to be a bit more defensive, but I don't have a strong opinion, your version is also fine. >And should any sk_err be consumed >here, too? (`err = sock_error(sk)` instead of `err = -sk->sk_err`) I'd stay with sock_error() to consume the error if it makes sense also for you. Thanks, Stefano