From: Jiri Slaby <jslaby@suse.cz>
To: Havard Skinnemoen <hskinnemoen@google.com>
Cc: Jiri Slaby <jirislaby@gmail.com>, Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@suse.de>,
Alan Cox <alan@linux.intel.com>
Subject: Re: [RFC] cdc-acm: Fix potential deadlock (lockdep warning)
Date: Wed, 23 Nov 2011 22:11:52 +0100 [thread overview]
Message-ID: <4ECD6198.20309@suse.cz> (raw)
In-Reply-To: <CAFQmdRbP3qXc2n_Qto0o3Lg1280gg7mPHVSY28S8nBT39YPPQQ@mail.gmail.com>
On 11/23/2011 10:08 PM, Havard Skinnemoen wrote:
> tty_port_close_start() takes port->lock, so if we try to do that,
> we'll turn a potential deadlock into a real one. Or did you mean
> something else?
I mean the other uses of port->count in your driver.
> I think I'll try to follow Alan's advice and use tty_port_close()
> instead of the split functions.
Yes, that's indeed the best approach. However you have to use them all:
tty_port_open, tty_port_hangup, tty_port_close. OR you would have to do
the locking of count properly.
thanks,
--
js
suse labs
next prev parent reply other threads:[~2011-11-23 21:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 3:38 tty related lockdep trace during bootup on 3.2-rc2 Dave Jones
2011-11-23 7:28 ` Havard Skinnemoen
2011-11-23 7:39 ` Cong Wang
2011-11-23 10:12 ` Jiri Slaby
2011-11-23 10:14 ` Jiri Slaby
2011-11-23 17:58 ` Havard Skinnemoen
2011-11-23 18:53 ` [RFC] cdc-acm: Fix potential deadlock (lockdep warning) Havard Skinnemoen
2011-11-23 19:22 ` Alan Cox
2011-11-23 19:22 ` Havard Skinnemoen
2011-11-23 19:44 ` Alan Cox
2011-11-23 21:03 ` Havard Skinnemoen
2011-11-23 21:59 ` Alan Cox
2011-11-23 19:34 ` Oliver Neukum
2011-11-23 22:00 ` Alan Cox
2011-11-23 19:55 ` Jiri Slaby
2011-11-23 21:08 ` Havard Skinnemoen
2011-11-23 21:11 ` Jiri Slaby [this message]
2011-11-23 21:19 ` Jiri Slaby
2011-11-27 21:37 ` [RFC v2] " Havard Skinnemoen
2011-11-28 18:15 ` Havard Skinnemoen
2011-11-23 7:29 ` tty related lockdep trace during bootup on 3.2-rc2 Cong Wang
2011-11-23 17:29 ` Havard Skinnemoen
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