From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Fw: [Bug 89831] New: timeout of TCP-sockets is *infinite* by default .. even if TCP-connection is already *broken* Date: Sat, 3 Jan 2015 17:33:30 -0800 Message-ID: <20150103173330.0f9b209b@urahara> 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-pa0-f46.google.com ([209.85.220.46]:65062 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751493AbbADBdj (ORCPT ); Sat, 3 Jan 2015 20:33:39 -0500 Received: by mail-pa0-f46.google.com with SMTP id lf10so26265183pab.33 for ; Sat, 03 Jan 2015 17:33:39 -0800 (PST) Received: from urahara (static-50-53-82-155.bvtn.or.frontiernet.net. [50.53.82.155]) by mx.google.com with ESMTPSA id oa8sm50372217pdb.84.2015.01.03.17.33.37 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 03 Jan 2015 17:33:38 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Begin forwarded message: Date: Tue, 16 Dec 2014 22:33:50 -0800 From: "bugzilla-daemon@bugzilla.kernel.org" To: "stephen@networkplumber.org" Subject: [Bug 89831] New: timeout of TCP-sockets is *infinite* by default .. even if TCP-connection is already *broken* https://bugzilla.kernel.org/show_bug.cgi?id=89831 Bug ID: 89831 Summary: timeout of TCP-sockets is *infinite* by default .. even if TCP-connection is already *broken* Product: Networking Version: 2.5 Kernel Version: all Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: IPV4 Assignee: shemminger@linux-foundation.org Reporter: polymorphm@gmail.com Regression: No Created attachment 160881 --> https://bugzilla.kernel.org/attachment.cgi?id=160881&action=edit test for catch infinite freezing (on TCP-sockets by default) on GNU/Linux good day! please, very sorry me for your time. :-) [and sorry for my bad english]. big problem in that fact: *most* application-programmers think that if TCP-connection is already *broken* -- that timeout of TCP-socket will *NOT* be *infinite*. (default system timeout). I prepared example code: https://gist.github.com/polymorphm/0e057402c9fa82547d72 (and this file "to-test.c" -- in attachment). this example code ("to-test.c") -- shows that if TCP-connection *broken* -- that timeout will *never* be reached (for broken TCP-connection. EVEN AFTER SOME DAYS). program "to-test.c" -- becomes to infinite freezing -- after "[step 8]": $ gcc -Wall -Werror -o to-test to-test.c && sudo ./to-test ***** begin of test ***** [step 1] creating socket... ***** INFO: is used SO_KEEPALIVE by default for TCP-sockets? answer: 0 ***** [step 2] connecting socket... [step 3] time waiting (1s)... [step 4] breaking down network... [wlp1s0] # ip link set down dev wlp1s0 [step 5] time waiting (15s)... [step 6] reestablishing up network... [wlp1s0] # ip link set up dev wlp1s0 [step 7] time waiting (1s)... [step 8] waiting of socket timeout (or we are freezed *infinity*?)... (infinite freeze -- at this point) probably, this issue-ticket will be marked as WONTFIX (and again: very sorry me for your time!). but this issue-ticket -- need at least for official canonical URL-link for answer to problem of default timeout of *broken* TCP-connection on GNU/Linux. when I speek with some application-programmers -- they say me: if GNU/Linux freeze at broken-TCP-connections (with default settings of socket) than is *bug* of GNU/Linux. and I maked this issue-ticket. sorry. -- You are receiving this mail because: You are the assignee for the bug.