From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Marcel Holtmann To: Jiri Kosina In-Reply-To: References: Date: Fri, 04 May 2007 08:41:53 +0200 Message-Id: <1178260913.25425.27.camel@violet> Mime-Version: 1.0 Cc: Andrew Morton , bluez-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [Bluez-devel] [PATCH] Bluetooth: postpone hci_dev unregistration Reply-To: BlueZ development List-Id: BlueZ development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Sender: bluez-devel-bounces@lists.sourceforge.net Errors-To: bluez-devel-bounces@lists.sourceforge.net Hi Jiri, > (I sent this a week ago but it seems to have got lost in other noise, > resending) > > From: Jiri Kosina > > Bluetooth: postpone hci_dev unregistration > > Commit b40df57 substituted bh_lock_sock() in hci_sock_dev_event() for > lock_sock() when unregistering HCI device, in order to prevent deadlock > against locking in l2cap_connect_cfm() from softirq context. > > This however introduces another problem - hci_sock_dev_event() for > HCI_DEV_UNREG can also be triggered in atomic context, in which calling > lock_sock() is not safe as it could sleep. Reported by Jeremy Fitzhardinge > at http://lkml.org/lkml/2007/4/23/271 > > This patch moves the detaching of sockets from hci_device into workqueue, > so that lock_sock() can be used safely. This requires movement of > deallocation of hci_dev - deallocating device just after > hci_unregister_dev() would be too soon, as it could happen before the > workqueue has been run. I saw the report on LKML, but I am not really comfortable with this approach. It feels like an ugly hack. This needs more thinking and I think that simplifying the looking between HCI and L2CAP should be the goal. Regards Marcel ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Bluez-devel mailing list Bluez-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-devel