From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Daniel Mack <daniel@caiaq.de>
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 17:28:41 +0100 [thread overview]
Message-ID: <20090721172841.36b20638@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20090721161928.GD13236@buzzloop.caiaq.de>
> 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.
Ok
>
> > > 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.
The hangup event means the physical hardware must no longer be touched so
that's already the case and we use it for a lot of things (from ISAPnP to
PCMCIA to USB).
The USB code does slightly misimplement it - it calls tty_hangup() in
usb_serial_disconnect when it should call tty_vhangup() as it needs the
event to be synchronous. That is the hangup of the tty should be done
before the USB layer can sneak off and free stuff.
I don't at this point see that as explaining the bug however
next prev parent reply other threads:[~2009-07-21 16:27 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 ` 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
2009-07-21 16:28 ` Alan Cox [this message]
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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