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authorMatthias Kaehlcke <mka@chromium.org>2019-01-03 03:11:20 +0300
committerMarcel Holtmann <marcel@holtmann.org>2019-01-22 11:51:20 +0300
commitc4f5627f7eeecde1bb6b646d8c0907b96dc2b2a6 (patch)
tree3caa470f040d4ce977c331a8367f2f70db561c79 /net/bluetooth
parent8c57983bf7a7987f957830614b1645bd6943f5af (diff)
downloadlinux-c4f5627f7eeecde1bb6b646d8c0907b96dc2b2a6.tar.xz
Bluetooth: Fix locking in bt_accept_enqueue() for BH context
With commit e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") lock_sock[_nested]() is used to acquire the socket lock before manipulating the socket. lock_sock[_nested]() may block, which is problematic since bt_accept_enqueue() can be called in bottom half context (e.g. from rfcomm_connect_ind()): [<ffffff80080d81ec>] __might_sleep+0x4c/0x80 [<ffffff800876c7b0>] lock_sock_nested+0x24/0x58 [<ffffff8000d7c27c>] bt_accept_enqueue+0x48/0xd4 [bluetooth] [<ffffff8000e67d8c>] rfcomm_connect_ind+0x190/0x218 [rfcomm] Add a parameter to bt_accept_enqueue() to indicate whether the function is called from BH context, and acquire the socket lock with bh_lock_sock_nested() if that's the case. Also adapt all callers of bt_accept_enqueue() to pass the new parameter: - l2cap_sock_new_connection_cb() - uses lock_sock() to lock the parent socket => process context - rfcomm_connect_ind() - acquires the parent socket lock with bh_lock_sock() => BH context - __sco_chan_add() - called from sco_chan_add(), which is called from sco_connect(). parent is NULL, hence bt_accept_enqueue() isn't called in this code path and we can ignore it - also called from sco_conn_ready(). uses bh_lock_sock() to acquire the parent lock => BH context Fixes: e16337622016 ("Bluetooth: Handle bt_accept_enqueue() socket atomically") Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Cc: stable@vger.kernel.org
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/af_bluetooth.c16
-rw-r--r--net/bluetooth/l2cap_sock.c2
-rw-r--r--net/bluetooth/rfcomm/sock.c2
-rw-r--r--net/bluetooth/sco.c2
4 files changed, 16 insertions, 6 deletions
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index deacc52d7ff1..8d12198eaa94 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -154,15 +154,25 @@ void bt_sock_unlink(struct bt_sock_list *l, struct sock *sk)
}
EXPORT_SYMBOL(bt_sock_unlink);
-void bt_accept_enqueue(struct sock *parent, struct sock *sk)
+void bt_accept_enqueue(struct sock *parent, struct sock *sk, bool bh)
{
BT_DBG("parent %p, sk %p", parent, sk);
sock_hold(sk);
- lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+
+ if (bh)
+ bh_lock_sock_nested(sk);
+ else
+ lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
+
list_add_tail(&bt_sk(sk)->accept_q, &bt_sk(parent)->accept_q);
bt_sk(sk)->parent = parent;
- release_sock(sk);
+
+ if (bh)
+ bh_unlock_sock(sk);
+ else
+ release_sock(sk);
+
parent->sk_ack_backlog++;
}
EXPORT_SYMBOL(bt_accept_enqueue);
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 686bdc6b35b0..a3a2cd55e23a 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1252,7 +1252,7 @@ static struct l2cap_chan *l2cap_sock_new_connection_cb(struct l2cap_chan *chan)
l2cap_sock_init(sk, parent);
- bt_accept_enqueue(parent, sk);
+ bt_accept_enqueue(parent, sk, false);
release_sock(parent);
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index aa0db1d1bd9b..b1f49fcc0478 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -988,7 +988,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
rfcomm_pi(sk)->channel = channel;
sk->sk_state = BT_CONFIG;
- bt_accept_enqueue(parent, sk);
+ bt_accept_enqueue(parent, sk, true);
/* Accept connection and return socket DLC */
*d = rfcomm_pi(sk)->dlc;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 529b38996d8b..9a580999ca57 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -193,7 +193,7 @@ static void __sco_chan_add(struct sco_conn *conn, struct sock *sk,
conn->sk = sk;
if (parent)
- bt_accept_enqueue(parent, sk);
+ bt_accept_enqueue(parent, sk, true);
}
static int sco_chan_add(struct sco_conn *conn, struct sock *sk,