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authorMat Martineau <mathewm@codeaurora.org>2012-05-02 09:42:00 -0700
committerGustavo Padovan <gustavo.padovan@collabora.co.uk>2012-05-16 16:13:51 -0300
commitef191aded58c5e6860b01f463818584a420a4d6b (patch)
tree3459b8a02ec5b4ef4566f139275c1c9dc234b3ce
parent35c84d76ee52f49fe2635d8cd686b5b658e8d892 (diff)
Bluetooth: Restore locking semantics when looking up L2CAP channels
As the comment for l2cap_get_chan_by_scid indicated, the function used to return a locked socket. The lock for the socket was acquired while the channel list was also locked. When locking was moved over to the l2cap_chan structure, the channel lock was no longer acquired with the channel list still locked. This made it possible for the l2cap_chan to be deleted after conn->chan_lock was released but before l2cap_chan_lock was called. Making the call to l2cap_chan_lock before releasing conn->chan_lock makes it impossible for the l2cap_chan to be deleted at the wrong time. Signed-off-by: Mat Martineau <mathewm@codeaurora.org> Reviewed-by: Ulisses Furquim <ulisses@profusion.mobi> Signed-off-by: Gustavo Padovan <gustavo@padovan.org>
-rw-r--r--net/bluetooth/l2cap_core.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index aea54f55c41d..285c5e13c7d5 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -98,13 +98,15 @@ static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16
}
/* Find channel with given SCID.
- * Returns locked socket */
+ * Returns locked channel. */
static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid)
{
struct l2cap_chan *c;
mutex_lock(&conn->chan_lock);
c = __l2cap_get_chan_by_scid(conn, cid);
+ if (c)
+ l2cap_chan_lock(c);
mutex_unlock(&conn->chan_lock);
return c;
@@ -3183,8 +3185,6 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
if (!chan)
return -ENOENT;
- l2cap_chan_lock(chan);
-
if (chan->state != BT_CONFIG && chan->state != BT_CONNECT2) {
struct l2cap_cmd_rej_cid rej;
@@ -3297,8 +3297,6 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
if (!chan)
return 0;
- l2cap_chan_lock(chan);
-
switch (result) {
case L2CAP_CONF_SUCCESS:
l2cap_conf_rfc_get(chan, rsp->data, len);
@@ -4631,8 +4629,6 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
return 0;
}
- l2cap_chan_lock(chan);
-
BT_DBG("chan %p, len %d", chan, skb->len);
if (chan->state != BT_CONNECTED)