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From: Olivier Sobrie <olivier@sobrie.be>
To: Dan Williams <dcbw@redhat.com>
Cc: Jan Dumon <j.dumon@option.com>,
	linux-usb@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] hso: fix deadlock when receiving bursts of data
Date: Mon, 7 Jul 2014 20:50:05 +0200	[thread overview]
Message-ID: <20140707185005.GA1105@thinkoso.home> (raw)
In-Reply-To: <1404751280.22000.11.camel@dcbw.local>

Hi Dan,

On Mon, Jul 07, 2014 at 11:41:20AM -0500, Dan Williams wrote:
> On Mon, 2014-07-07 at 11:06 +0200, Olivier Sobrie wrote:
> > When the module sends bursts of data, sometimes a deadlock happens in
> > the hso driver when the tty buffer doesn't get the chance to be flushed
> > quickly enough.
> > 
> > To avoid this, first, we remove the endless while loop in
> > put_rx_bufdata() which is the root cause of the deadlock.
> > Secondly, when there is no room anymore in the tty buffer, we set up a
> > timer of 100 msecs to give a chance to the upper layer to flush the tty
> > buffer and make room for new data.
> 
> I assume this problem happens when using PPP for data transfer, instead
> of using the network port that the modules expose?  Or maybe the NMEA
> port?  I can't imagine that AT commands would make this happen...

Yes it happens when using ppp for data transfer.
The transfer of a large file sometimes triggers the problem.

-- 
Olivier

  reply	other threads:[~2014-07-07 18:49 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-07  9:06 [PATCH 1/2] hso: remove unused workqueue Olivier Sobrie
2014-07-07  9:06 ` [PATCH 2/2] hso: fix deadlock when receiving bursts of data Olivier Sobrie
2014-07-07  9:13   ` David Laight
2014-07-07 10:42     ` Olivier Sobrie
2014-07-07 12:55       ` David Laight
2014-07-07 13:38         ` Olivier Sobrie
2014-07-07 16:41   ` Dan Williams
2014-07-07 18:50     ` Olivier Sobrie [this message]
2014-07-08 23:16   ` David Miller
2014-07-10 14:28     ` Olivier Sobrie
2014-07-10 14:37       ` David Laight
2014-07-10 15:50         ` One Thousand Gnomes
2014-07-10 15:55           ` David Laight
2014-07-10 21:20             ` One Thousand Gnomes
2014-07-11  9:18           ` Olivier Sobrie
2014-07-11  9:28             ` David Laight
2014-07-11 12:05               ` Olivier Sobrie
2014-07-11 13:05   ` [PATCH v2 " Olivier Sobrie
2014-07-11 18:36     ` David Miller

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