From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Fw: [Bug 194723] connect() to localhost stalls after 4.9 -> 4.10 upgrade Date: Thu, 2 Mar 2017 10:32:49 -0800 Message-ID: <20170302103249.671ef5a5@xeon-e3> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from mail-pg0-f47.google.com ([74.125.83.47]:34477 "EHLO mail-pg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750707AbdCBSdw (ORCPT ); Thu, 2 Mar 2017 13:33:52 -0500 Received: by mail-pg0-f47.google.com with SMTP id 16so553718pga.1 for ; Thu, 02 Mar 2017 10:32:51 -0800 (PST) Received: from xeon-e3 (204-195-18-65.wavecable.com. [204.195.18.65]) by smtp.gmail.com with ESMTPSA id p77sm14392903pfj.99.2017.03.02.10.32.50 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 02 Mar 2017 10:32:50 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Begin forwarded message: Date: Wed, 01 Mar 2017 12:04:45 +0000 From: bugzilla-daemon@bugzilla.kernel.org To: stephen@networkplumber.org Subject: [Bug 194723] connect() to localhost stalls after 4.9 -> 4.10 upgrade https://bugzilla.kernel.org/show_bug.cgi?id=194723 --- Comment #2 from Lutz Vieweg (lvml@5t9.de) --- Using tcpdump I found that when the connect() stalls, the initial SYN packet appears at the "lo" interface, and is re-sent multiple times, but no ACK packet is ever returned. Error case with linux-4.10: > 12:57:25.685640 IP 127.0.0.1.44074 > 127.0.0.1.dnp-sec: Flags [S], seq > 1952288470, win 43690, options [mss 65495,sackOK,TS val 1942998659 ecr > 0,nop,wscale 7], length 0 > 12:57:26.728890 IP 127.0.0.1.44074 > 127.0.0.1.dnp-sec: Flags [S], seq > 1952288470, win 43690, options [mss 65495,sackOK,TS val 1942999703 ecr > 0,nop,wscale 7], length 0 > 12:57:28.776935 IP 127.0.0.1.44074 > 127.0.0.1.dnp-sec: Flags [S], seq > 1952288470, win 43690, options [mss 65495,sackOK,TS val 1943001751 ecr > 0,nop,wscale 7], length 0 ... Normal case: > 13:01:43.037135 IP 127.0.0.1.44362 > 127.0.0.1.dnp-sec: Flags [S], seq > 3181010757, win 43690, options [mss 65495,sackOK,TS val 3314900273 ecr > 0,nop,wscale 7], length 0 > 13:01:43.037171 IP 127.0.0.1.dnp-sec > 127.0.0.1.44362: Flags [S.], seq > 1934682061, ack 3181010758, win 43690, options [mss 65495,sackOK,TS val > 2947413993 ecr 3314900273,nop,wscale 7], length 0 > 13:01:43.037196 IP 127.0.0.1.44362 > 127.0.0.1.dnp-sec: Flags [.], ack 1, win > 342, options [nop,nop,TS val 3314900273 ecr 2947413993], length 0 According to strace, the listening process does not even leave the select() call it uses to wait for incoming connections to accept in the error case. -- You are receiving this mail because: You are the assignee for the bug.