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Date: Mon, 07 Nov 2011 18:52:30 +0400
From: Ilya Zykov <ilya@ilyx.ru>
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To: Alan Cox <alan@linux.intel.com>
CC: Greg Kroah-Hartman <gregkh@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: PROBLEM: Race condition in tty buffer's function flush_to_ldisc().
References: <4EB7BD9A.7070600@ilyx.ru>	<20111107115802.23201d45@bob.linux.org.uk>	<4EB7CCFF.5090304@ilyx.ru>	<20111107130643.07e84fca@bob.linux.org.uk>	<4EB7E0C6.7050909@ilyx.ru> <20111107145005.68ca1050@bob.linux.org.uk>
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Alan Cox wrote:

>> Of course I know about tty_buffer_flush(), it only read TTY_FLUSHING,
>> it can't change TTY_FLUSHING, if flush_to_ldisc() single threaded,
>> we can change TTY_FLUSHING only in one place in one time(in
>> flush_to_ldisc()), therefor we can use only "set_bit(TTY_FLUSHING,
>> &tty->flags)" without test.
> 
> Yes.. if you can pin down why in your testing you see the other case
> sometimes being true.
> 
> Alan
>  
> 
> 

OK, I try.
Ilya.