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From: Sasha Levin <sasha.levin@oracle.com>
To: David Miller <davem@davemloft.net>
Cc: samuel@sortiz.org, gregkh@linuxfoundation.org, jslaby@suse.cz,
	peter@hurleysoftware.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ircomm: release tty before sleeping potentially indefintely
Date: Sun, 03 Mar 2013 18:17:38 -0500	[thread overview]
Message-ID: <5133DA12.8020907@oracle.com> (raw)
In-Reply-To: <20130303.174739.1195645942179862011.davem@davemloft.net>

On 03/03/2013 05:47 PM, David Miller wrote:
> From: Sasha Levin <sasha.levin@oracle.com>
> Date: Sun,  3 Mar 2013 17:35:53 -0500
> 
>> ircomm_tty_block_til_ready would hold tty lock while blocking. Since the sleep
>> might take a long time we can prevent other processes from accessing the tty,
>> causing hung tasks and a dead tty.
>>
>> Diagnosed-by: Peter Hurley <peter@hurleysoftware.com>
>> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> 
> But then you invalidate all of the tty state tests made under
> the lock at the beginning of this function, before enterring
> the loop.  If you drop the lock, those pieces of state could
> change.
> 
> I'm not applying this.

I'm unsure. A similar patch was applied back in 2010 that does the same thing
to a bunch of drivers, including the core tty code (e142a31da "tty: release
BTM while sleeping in block_til_ready").

This IR code looks very much like tty_port_block_til_ready() where it was
okay to do that change, so I should be the same with ircomm_tty_block_til_ready.


Thanks,
Sasha

  reply	other threads:[~2013-03-03 23:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-03 22:35 [PATCH] ircomm: release tty before sleeping potentially indefintely Sasha Levin
2013-03-03 22:47 ` David Miller
2013-03-03 23:17   ` Sasha Levin [this message]
2013-03-04  0:31     ` David Miller
2013-03-04  0:04   ` Peter Hurley
2013-03-04  0:33     ` David Miller
2013-03-04  1:06       ` Peter Hurley
2013-03-04  2:36         ` David Miller
2013-03-04  4:24           ` Peter Hurley
2013-03-05 16:09             ` [PATCH 0/4] other ircomm_tty fixes (was Re: [PATCH] ircomm: release tty before sleeping potentially indefintely) Peter Hurley
2013-03-05 16:09               ` [PATCH 1/4] net/irda: Fix port open counts Peter Hurley
2013-03-05 16:09               ` [PATCH 2/4] net/irda: Hold port lock while bumping blocked_open Peter Hurley
2013-03-05 16:09               ` [PATCH 3/4] net/irda: Use barrier to set task state Peter Hurley
2013-03-05 16:09               ` [PATCH 4/4] net/irda: Raise dtr in non-blocking open Peter Hurley
2013-03-06  4:44               ` [PATCH 0/4] other ircomm_tty fixes David Miller
2013-03-04  4:30           ` [PATCH] ircomm: release tty before sleeping potentially indefintely Peter Hurley
2013-03-04  2:23   ` Peter Hurley

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