From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx102.postini.com [74.125.245.102]) by kanga.kvack.org (Postfix) with SMTP id 52EAC6B005D for ; Thu, 10 Jan 2013 21:01:19 -0500 (EST) Received: by mail-pb0-f47.google.com with SMTP id un1so648083pbc.20 for ; Thu, 10 Jan 2013 18:01:18 -0800 (PST) Subject: Re: 3.8-rc2/rc3 write() blocked on CLOSE_WAIT TCP socket From: Eric Dumazet In-Reply-To: <20130111004915.GA15415@dcvr.yhbt.net> References: <20130111004915.GA15415@dcvr.yhbt.net> Content-Type: text/plain; charset="UTF-8" Date: Thu, 10 Jan 2013 18:01:15 -0800 Message-ID: <1357869675.27446.2962.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Eric Wong Cc: netdev@vger.kernel.org, Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rik van Riel , Minchan Kim , Andrew Morton , Linus Torvalds On Fri, 2013-01-11 at 00:49 +0000, Eric Wong wrote: > The below Ruby script reproduces the issue for me with write() > getting stuck, usually with a few iterations (sometimes up to 100). > > I've reproduced this with 3.8-rc2 and rc3, even with Mel's partial > revert patch in <20130110194212.GJ13304@suse.de> applied. > > I can not reproduce this with 3.7.1+ > stable-queue 2afd72f59c518da18853192ceeebead670ced5ea > So this seems to be a new bug from the 3.8 cycle... > > Fortunately, this bug far easier for me to reproduce than the ppoll+send > (toosleepy) failures. > > Both socat and ruby (Ruby 1.8, 1.9, 2.0 should all work), along with > common shell tools (dd, sh, cat) are required for testing this: > > # 100 iterations, raise/lower the number if needed > ruby the_script_below.rb 100 > > lsof -p 15236 reveals this: > ruby 15236 ew 5u IPv4 23066 0t0 TCP localhost:33728->localhost:38658 (CLOSE_WAIT) Hmm, it might be commit c3ae62af8e755ea68380fb5ce682e60079a4c388 tcp: should drop incoming frames without ACK flag set It seems RST should be allowed to not have ACK set. I'll send a fix, thanks ! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org