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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Eric Wong <normalperson@yhbt.net>
Cc: netdev@vger.kernel.org, Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Rik van Riel <riel@redhat.com>, Minchan Kim <minchan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: 3.8-rc2/rc3 write() blocked on CLOSE_WAIT TCP socket
Date: Thu, 10 Jan 2013 18:01:15 -0800	[thread overview]
Message-ID: <1357869675.27446.2962.camel@edumazet-glaptop> (raw)
In-Reply-To: <20130111004915.GA15415@dcvr.yhbt.net>

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 !





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  reply	other threads:[~2013-01-11  2:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-11  0:49 Eric Wong
2013-01-11  2:01 ` Eric Dumazet [this message]
2013-01-11  2:18   ` Eric Dumazet
2013-01-11  2:40     ` Neal Cardwell
2013-01-11  2:50     ` Eric Wong
2013-01-11  6:49     ` David Miller

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