Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760380AbXEPMQT (ORCPT ); Wed, 16 May 2007 08:16:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756075AbXEPMQF (ORCPT ); Wed, 16 May 2007 08:16:05 -0400 Received: from coyote.holtmann.net ([217.160.111.169]:53233 "EHLO mail.holtmann.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756240AbXEPMQE (ORCPT ); Wed, 16 May 2007 08:16:04 -0400 Subject: Re: 2.6.21-rc7: BUG: sleeping function called from invalid context at net/core/sock.c:1523 From: Marcel Holtmann To: Satyam Sharma Cc: Jiri Kosina , Greg KH , Jeremy Fitzhardinge , maxk@qualcomm.com, bluez-devel@lists.sourceforge.net, Cedric Le Goater , Linux Kernel Mailing List , netdev@vger.kernel.org In-Reply-To: References: <462D1B09.9050005@goop.org> <1179315904.10069.67.camel@violet> Content-Type: text/plain Date: Wed, 16 May 2007 14:16:15 +0200 Message-Id: <1179317775.10069.77.camel@violet> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2814 Lines: 74 Hi Satyam, > > > > > > (later) > > > > > > I Googled a bit to see if this problem was faced elsewhere in the kernel > > > > > > too. Saw the following commit by Ingo Molnar > > > > > > (9883a13c72dbf8c518814b6091019643cdb34429): > > > > > > - lock_sock(sock->sk); > > > > > > + local_bh_disable(); > > > > > > + bh_lock_sock_nested(sock->sk); > > > > > > rc = selinux_netlbl_socket_setsid(sock, sksec->sid); > > > > > > - release_sock(sock->sk); > > > > > > + bh_unlock_sock(sock->sk); > > > > > > + local_bh_enable(); > > > > > > Is it _really_ *this* simple? > > > > > [...] > > > > > actually this *seems* to be proper solution also for our case, thanks for > > > > > pointing this out. I will think about it once again, do some more tests > > > > > with this locking scheme, and will let you know. > > > > > > > > Yes, I can almost confirm that this (open-coding of spin_lock_bh, > > > > effectively) is the proper solution (Rusty's unreliable guide to > > > > kernel-locking needs to be next to every developer's keyboard :-) > > > > I also came across this idiom in other places in the networking code > > > > so it seems to be pretty much the standard way. I wish I owned > > > > bluetooth hardware, could've tested this for you myself. > > > > > > does this mean we should revert previous changes to the locking or only > > > apply this on top of it? > > > > I've fixed a simple patch on top of 2.6.22-rc1 below. > > Eek, please ignore previous one. This one's correct. > > Signed-off-by: Satyam Sharma > > diff -ruNp a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c > --- a/net/bluetooth/hci_sock.c 2007-05-16 17:31:06.000000000 +0530 > +++ b/net/bluetooth/hci_sock.c 2007-05-16 17:38:35.000000000 +0530 > @@ -665,7 +665,8 @@ static int hci_sock_dev_event(struct not > /* Detach sockets from device */ > read_lock(&hci_sk_list.lock); > sk_for_each(sk, node, &hci_sk_list.head) { > - lock_sock(sk); > + local_bh_disable(); > + bh_lock_sock_nested(sk); > if (hci_pi(sk)->hdev == hdev) { > hci_pi(sk)->hdev = NULL; > sk->sk_err = EPIPE; > @@ -674,7 +675,8 @@ static int hci_sock_dev_event(struct not > > hci_dev_put(hdev); > } > - release_sock(sk); > + bh_unlock_sock(sk); > + local_bh_enable(); > } > read_unlock(&hci_sk_list.lock); > } since Jiri has a good test case for it, I leave it to him for testing. If he confirms that this fixes the locking issues, then this is Signed-off-by: Marcel Holtmann Regards Marcel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/