Re: bluetooth lockdep trace. (.25rc5-git4)

From: Dave Young
Date: Tue Apr 01 2008 - 04:59:02 EST

On Tue, Apr 1, 2008 at 4:59 PM, Dave Young <hidave.darkstar@xxxxxxxxx> wrote:
> marcel@xxxxxxxxxxxx
> Bcc:
> Subject: Re: bluetooth lockdep trace. (.25rc5-git4)
> Reply-To:
> In-Reply-To: <20080328.182021.46780895.davem@xxxxxxxxxxxxx>
>
> On Fri, Mar 28, 2008 at 06:20:21PM -0700, David Miller wrote:
> > From: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
> > Date: Thu, 27 Mar 2008 12:21:56 -0400
> >
> > > Mar 27 08:10:57 localhost kernel: Pid: 3611, comm: obex-data-serve Not tainted 2.6.25-0.121.rc5.git4.fc9 #1
> > > Mar 27 08:10:57 localhost kernel: [__lock_acquire+2287/3089] __lock_acquire+0x8ef/0xc11
> > > Mar 27 08:10:57 localhost kernel: [sched_clock+8/11] ? sched_clock+0x8/0xb
> > > Mar 27 08:10:57 localhost kernel: [lock_acquire+106/144] lock_acquire+0x6a/0x90
> > > Mar 27 08:10:57 localhost kernel: [<f8bd9321>] ? l2cap_sock_bind+0x29/0x108 [l2cap]
> > > Mar 27 08:10:57 localhost kernel: [lock_sock_nested+182/198] lock_sock_nested+0xb6/0xc6
> > > Mar 27 08:10:57 localhost kernel: [<f8bd9321>] ? l2cap_sock_bind+0x29/0x108 [l2cap]
> > > Mar 27 08:10:57 localhost kernel: [security_socket_post_create+22/27] ? security_socket_post_create+0x16/0x1b
> > > Mar 27 08:10:57 localhost kernel: [__sock_create+388/472] ? __sock_create+0x184/0x1d8
> > > Mar 27 08:10:57 localhost kernel: [<f8bd9321>] l2cap_sock_bind+0x29/0x108 [l2cap]
> > > Mar 27 08:10:57 localhost kernel: [kernel_bind+10/13] kernel_bind+0xa/0xd
> > > Mar 27 08:10:57 localhost kernel: [<f8dad3d7>] rfcomm_dlc_open+0xc8/0x294 [rfcomm]
> > > Mar 27 08:10:57 localhost kernel: [lock_sock_nested+187/198] ? lock_sock_nested+0xbb/0xc6
> > > Mar 27 08:10:57 localhost kernel: [<f8dae18c>] rfcomm_sock_connect+0x8b/0xc2 [rfcomm]
> > > Mar 27 08:10:57 localhost kernel: [sys_connect+96/125] sys_connect+0x60/0x7d
> > > Mar 27 08:10:57 localhost kernel: [__lock_acquire+1370/3089] ? __lock_acquire+0x55a/0xc11
> > > Mar 27 08:10:57 localhost kernel: [sys_socketcall+140/392] sys_socketcall+0x8c/0x188
> > > Mar 27 08:10:57 localhost kernel: [syscall_call+7/11] syscall_call+0x7/0xb
> >
> > rfcomm connect locks the socket, then does rfcomm_dlc_open which in
> > turn can do a l2cap_sock_bind on a seperate second socket which in
> > turn locks that second socket.
> >
> > Both of these sockets are AF_BLUETOOTH family, so lockdep thinks there
> > is a locking conflict, even though what is happening here is perfectly
> > fine since the two sockets are totally different AF_BLUETOOTH
> > sub-types.
> >
> > Bluetooth will need to use sock_lock_init_class_and_name() and
> > lock sub-classes per AF_BLUETOOTH socket sub-type.
> >
> > David, could you or someone else work on this?
>
> Does this fix the problem?
>
> ---
> 'rfcomm connect' will trigger lockdep warnings which is caused by
> locking diffrent kinds of bluetooth sockets at the same time.
>
> So using sub-classes per AF_BLUETOOTH sub-type for lockdep.
>
> Thanks for the hints from dave jones.
>
>
> Signed-off-by: Dave Young <hidave.darkstar@xxxxxxxxx>
>
> ---
> net/bluetooth/af_bluetooth.c | 40 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff -upr linux/net/bluetooth/af_bluetooth.c linux.new/net/bluetooth/af_bluetooth.c
> --- linux/net/bluetooth/af_bluetooth.c 2008-04-01 16:09:17.000000000 +0800
> +++ linux.new/net/bluetooth/af_bluetooth.c 2008-04-01 16:08:52.000000000 +0800
> @@ -53,6 +53,30 @@
> /* Bluetooth sockets */
> #define BT_MAX_PROTO 8
> static struct net_proto_family *bt_proto[BT_MAX_PROTO];
> +
> +static struct lock_class_key bt_slock_key[BT_MAX_PROTO];
> +static struct lock_class_key bt_lock_key[BT_MAX_PROTO];
> +static const char *bt_key_strings[BT_MAX_PROTO] = {
> + "sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_HCI",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_SCO",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_BNEP",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_CMTP",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_HIDP",
> + "sk_lock-AF_BLUETOOTH-BTPROTO_AVDTP",
> +};
> +
> +static const char *bt_slock_key_strings[BT_MAX_PROTO] = {
> + "slock-AF_BLUETOOTH-BTPROTO_L2CAP",
> + "slock-AF_BLUETOOTH-BTPROTO_HCI",
> + "slock-AF_BLUETOOTH-BTPROTO_SCO",
> + "slock-AF_BLUETOOTH-BTPROTO_RFCOMM",
> + "slock-AF_BLUETOOTH-BTPROTO_BNEP",
> + "slock-AF_BLUETOOTH-BTPROTO_CMTP",
> + "slock-AF_BLUETOOTH-BTPROTO_HIDP",
> + "slock-AF_BLUETOOTH-BTPROTO_AVDTP",
> +};
> static DEFINE_RWLOCK(bt_proto_lock);
>
> int bt_sock_register(int proto, struct net_proto_family *ops)
> @@ -95,6 +119,21 @@ int bt_sock_unregister(int proto)
> }
> EXPORT_SYMBOL(bt_sock_unregister);
>
> +static void bt_reclassify_sock_lock(struct socket *sock, int proto)
> +{
> + struct sock *sk = sock->sk;
> +
> + if (!sk)
> + return;
> + BUG_ON(sock_owned_by_user(sk));
> +
> + sock_lock_init_class_and_name(sk,
> + bt_slock_key_strings[proto],
> + &bt_slock_key[proto],
> + bt_key_strings[proto],
> + &bt_lock_key[proto]);
> +}
> +
> static int bt_sock_create(struct net *net, struct socket *sock, int proto)
> {
> int err;
> @@ -117,6 +156,7 @@ static int bt_sock_create(struct net *ne
>
> if (bt_proto[proto] && try_module_get(bt_proto[proto]->owner)) {
> err = bt_proto[proto]->create(net, sock, proto);
> + bt_reclassify_sock_lock(sock, proto);
> module_put(bt_proto[proto]->owner);
> }
>
>

Sorry, the subject was cut by my mistake, please don't mind.

Regards
dave
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