Return-Path: <cyrus@holtmann.org>
Subject: Re: [BUG net-2.6] bluetooth/rfcomm : sleeping function called from
 invalid context at mm/slub.c:1719
From: Marcel Holtmann <marcel@holtmann.org>
To: Dave Young <hidave.darkstar@gmail.com>
Cc: "Gustavo F. Padovan" <gustavo@padovan.org>,
	Oliver Hartkopp <oliver@hartkopp.net>,
	Linux Netdev List <netdev@vger.kernel.org>,
	linux-bluetooth@vger.kernel.org,
	"Gustavo F. Padovan" <gustavo@las.ic.unicamp.br>
In-Reply-To: <20091009004452.GA2395@darkstar>
References: <4AC59D8A.6000102@hartkopp.net>
	 <a8e1da0910020401m2fb8493ax95ff55a3b66131a5@mail.gmail.com>
	 <4AC6247E.7050308@hartkopp.net> <20091003070622.GA4110@darkstar>
	 <4AC71CAA.9090704@hartkopp.net>
	 <a8e1da0910032026m66200c08jf9201bbfe34b2f30@mail.gmail.com>
	 <20091004180635.GA11272@vigoh>  <20091009004452.GA2395@darkstar>
Content-Type: text/plain
Date: Sat, 10 Oct 2009 12:38:32 +0200
Message-Id: <1255171112.19127.1.camel@localhost.localdomain>
Mime-Version: 1.0
Sender: linux-bluetooth-owner@vger.kernel.org
List-ID: <linux-bluetooth.vger.kernel.org>

Hi Dave,

> > * Dave Young <hidave.darkstar@gmail.com> [2009-10-04 11:26:17 +0800]:
> > 
> > > 
> > > I can reproduce the bug.
> > > 
> > > It's probably caused by the l2cap changes by  Gustavo F. Padovan
> > > <gustavo@las.ic.unicamp.br>, I didn't see such problem after reverting
> > > Gustavo's patch series.
> > 
> > I can't reproduce the bug. I'm trying to reproduce it to figure out what of
> > my changes cause it.
> > 
> > I' running
> > 
> > $ dund -snu -i 00:11:67:CD:0F:CB # to pretend to be dialup/telephone
> > 
> > and on the other side 
> > 
> > $ rfcomm bind 0 00:11:67:CD:0F:CB 1
> > $ wvdial  # wvdial to /dev/rfcomm0
> > 
> > Both sides are on the same machine. Do you see any real difference
> > between my try and the call that get the bug?
> > 
> 
> Hi oliver
> 
> Could try following patch?
> ---
> 
> When shutdown ppp connection, lockdep waring about non-static key
> will happen, it is caused by the lock is not initialized properly
> at that time.
> 
> Fix with tuning the lock/skb_queue_head init order
> 
> [   94.339261] INFO: trying to register non-static key.
> [   94.342509] the code is fine but needs lockdep annotation.
> [   94.342509] turning off the locking correctness validator.
> [   94.342509] Pid: 0, comm: swapper Not tainted 2.6.31-mm1 #2
> [   94.342509] Call Trace:
> [   94.342509]  [<c0248fbe>] register_lock_class+0x58/0x241
> [   94.342509]  [<c024b5df>] ? __lock_acquire+0xb57/0xb73
> [   94.342509]  [<c024ab34>] __lock_acquire+0xac/0xb73
> [   94.342509]  [<c024b7fa>] ? lock_release_non_nested+0x17b/0x1de
> [   94.342509]  [<c024b662>] lock_acquire+0x67/0x84
> [   94.342509]  [<c04cd1eb>] ? skb_dequeue+0x15/0x41
> [   94.342509]  [<c054a857>] _spin_lock_irqsave+0x2f/0x3f
> [   94.342509]  [<c04cd1eb>] ? skb_dequeue+0x15/0x41
> [   94.342509]  [<c04cd1eb>] skb_dequeue+0x15/0x41
> [   94.342509]  [<c054a648>] ? _read_unlock+0x1d/0x20
> [   94.342509]  [<c04cd641>] skb_queue_purge+0x14/0x1b
> [   94.342509]  [<fab94fdc>] l2cap_recv_frame+0xea1/0x115a [l2cap]
> [   94.342509]  [<c024b5df>] ? __lock_acquire+0xb57/0xb73
> [   94.342509]  [<c0249c04>] ? mark_lock+0x1e/0x1c7
> [   94.342509]  [<f8364963>] ? hci_rx_task+0xd2/0x1bc [bluetooth]
> [   94.342509]  [<fab95346>] l2cap_recv_acldata+0xb1/0x1c6 [l2cap]
> [   94.342509]  [<f8364997>] hci_rx_task+0x106/0x1bc [bluetooth]
> [   94.342509]  [<fab95295>] ? l2cap_recv_acldata+0x0/0x1c6 [l2cap]
> [   94.342509]  [<c02302c4>] tasklet_action+0x69/0xc1
> [   94.342509]  [<c022fbef>] __do_softirq+0x94/0x11e
> [   94.342509]  [<c022fcaf>] do_softirq+0x36/0x5a
> [   94.342509]  [<c022fe14>] irq_exit+0x35/0x68
> [   94.342509]  [<c0204ced>] do_IRQ+0x72/0x89
> [   94.342509]  [<c02038ee>] common_interrupt+0x2e/0x34
> [   94.342509]  [<c024007b>] ? pm_qos_add_requirement+0x63/0x9d
> [   94.342509]  [<c038e8a5>] ? acpi_idle_enter_bm+0x209/0x238
> [   94.342509]  [<c049d238>] cpuidle_idle_call+0x5c/0x94
> [   94.342509]  [<c02023f8>] cpu_idle+0x4e/0x6f
> [   94.342509]  [<c0534153>] rest_init+0x53/0x55
> [   94.342509]  [<c0781894>] start_kernel+0x2f0/0x2f5
> [   94.342509]  [<c0781091>] i386_start_kernel+0x91/0x96
> 
> Reported-by: Oliver Hartkopp <oliver@hartkopp.net>
> Signed-off-by: Dave Young <hidave.darkstar@gmail.com>

actually Gustavo send a patch titled "Initialize variables and timers
for both channel's sides" that should fix this, too. Can we test that
patch before I include this one.

Regards

Marcel