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author | Johan Hedberg <johan.hedberg@intel.com> | 2014-11-12 22:22:21 +0200 |
---|---|---|
committer | Marcel Holtmann <marcel@holtmann.org> | 2014-11-13 07:49:09 +0100 |
commit | abe84903a8efc6b83fa92161429e0e3a28bde15c (patch) | |
tree | 3b1b90b1c170c41bbd6fcdae92e8726024c37ade /net/bluetooth/l2cap_sock.c | |
parent | 24ccb9f4f7a3a5a867bbc880019cdb4b41176b63 (diff) | |
download | op-kernel-dev-abe84903a8efc6b83fa92161429e0e3a28bde15c.zip op-kernel-dev-abe84903a8efc6b83fa92161429e0e3a28bde15c.tar.gz |
Bluetooth: Use proper nesting annotation for l2cap_chan lock
By default lockdep considers all L2CAP channels equal. This would mean
that we get warnings if a channel is locked when another one's lock is
tried to be acquired in the same thread. This kind of inter-channel
locking dependencies exist in the form of parent-child channels as well
as any channel wishing to elevate the security by requesting procedures
on the SMP channel.
To eliminate the chance for these lockdep warnings we introduce a
nesting level for each channel and use that when acquiring the channel
lock. For now there exists the earlier mentioned three identified
categories: SMP, "normal" channels and parent channels (i.e. those in
BT_LISTEN state). The nesting level is defined as atomic_t since we need
access to it before the lock is actually acquired.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/bluetooth/l2cap_sock.c')
-rw-r--r-- | net/bluetooth/l2cap_sock.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index ad1cf82..f1a5156 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -285,6 +285,12 @@ static int l2cap_sock_listen(struct socket *sock, int backlog) sk->sk_max_ack_backlog = backlog; sk->sk_ack_backlog = 0; + /* Listening channels need to use nested locking in order not to + * cause lockdep warnings when the created child channels end up + * being locked in the same thread as the parent channel. + */ + atomic_set(&chan->nesting, L2CAP_NESTING_PARENT); + chan->state = BT_LISTEN; sk->sk_state = BT_LISTEN; @@ -1497,6 +1503,9 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent) l2cap_chan_set_defaults(chan); } + /* Set default lock nesting level */ + atomic_set(&chan->nesting, L2CAP_NESTING_NORMAL); + /* Default config options */ chan->flush_to = L2CAP_DEFAULT_FLUSH_TO; |