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From: Daniel Mack <daniel@caiaq.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	Kernel development list <linux-kernel@vger.kernel.org>,
	USB list <linux-usb@vger.kernel.org>
Subject: Re: [PATCH] [usb-serial] fix Ooops on uplug
Date: Tue, 21 Jul 2009 18:19:28 +0200	[thread overview]
Message-ID: <20090721161928.GD13236@buzzloop.caiaq.de> (raw)
In-Reply-To: <20090721171625.6e2c54e4@lxorguk.ukuu.org.uk>

On Tue, Jul 21, 2009 at 05:16:25PM +0100, Alan Cox wrote:
> > I got something similar with a pl2303 device, though not a crash.  I 
> > plugged in the device, opened /dev/ttyUSB0, unplugged the device, then 
> > tried to read from the open file descriptor.  The read provoked this:
> 
> That looks like it occurs after the read, however that trace shows the
> close() method being called off sys_close() which in turn means a hang up
> didn't occur when it was unplugged.

It was, at least in my case. Did some printk debugging and it showed
that the hangup callback was entered what freed the serial device.

> > This is only a lockdep warning, and I don't understand its
> > significance.  Even worse, when I plugged in a USB flash drive
> > afterward this appeared:
> 
> Looks like something freed the resources but didn't hang up when the
> disconnect occurred

Probably the real fix would be to let the tty layer know the device died
from the hangup handler.


  reply	other threads:[~2009-07-21 16:19 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20090720155502.50b84ae9@lxorguk.ukuu.org.uk>
2009-07-20 17:51 ` [PATCH] [usb-serial] fix Ooops on uplug Daniel Mack
2009-07-20 22:48   ` Alan Cox
2009-07-20 21:58     ` Daniel Mack
2009-07-20 23:45       ` Alan Cox
2009-07-21 15:53         ` Alan Stern
2009-07-21 15:56           ` Daniel Mack
2009-07-21 16:00             ` Alan Cox
2009-07-21 16:11               ` Alan Stern
2009-07-21 16:18                 ` Alan Cox
2009-07-21 16:16           ` Alan Cox
2009-07-21 16:19             ` Daniel Mack [this message]
2009-07-21 16:28               ` Alan Cox
2009-07-21 18:36             ` Alan Stern
2009-07-21 19:21               ` Alan Cox
2009-07-21 21:38                 ` Alan Stern
2009-07-21 22:55                   ` Alan Cox
2009-07-22 14:44                     ` Alan Stern
2009-07-22 16:17                       ` Alan Cox
2009-07-22 18:21                         ` Alan Stern
2009-07-22 22:35                           ` Alan Cox
2009-07-22 22:45                             ` Alan Stern
2009-07-22 22:48                               ` Alan Cox
2009-07-20 23:32   ` Alan Cox

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