提交 7ab56c3a 编写于 作者: J Jukka Taimisto 提交者: Marcel Holtmann

Bluetooth: Fix deadlock in l2cap_conn_del()

A deadlock occurs when PDU containing invalid SMP opcode is received on
Security Manager Channel over LE link and conn->pending_rx_work worker
has not run yet.

When LE link is created l2cap_conn_ready() is called and before
returning it schedules conn->pending_rx_work worker to hdev->workqueue.
Incoming data to SMP fixed channel is handled by l2cap_recv_frame()
which calls smp_sig_channel() to handle the SMP PDU. If
smp_sig_channel() indicates failure l2cap_conn_del() is called to delete
the connection. When deleting the connection, l2cap_conn_del() purges
the pending_rx queue and calls flush_work() to wait for the
pending_rx_work worker to complete.

Since incoming data is handled by a worker running from the same
workqueue as the pending_rx_work is being scheduled on, we will deadlock
on waiting for pending_rx_work to complete.

This patch fixes the deadlock by calling cancel_work_sync() instead of
flush_work().
Signed-off-by: NJukka Taimisto <jtt@codenomicon.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
上级 f8680f12
master alk-4.19.24 alk-4.19.30 alk-4.19.34 alk-4.19.36 alk-4.19.43 alk-4.19.48 alk-4.19.57 ck-4.19.67 ck-4.19.81 ck-4.19.91 github/fork/deepanshu1422/fix-typo-in-comment github/fork/haosdent/fix-typo linux-next v4.19.91 v4.19.90 v4.19.89 v4.19.88 v4.19.87 v4.19.86 v4.19.85 v4.19.84 v4.19.83 v4.19.82 v4.19.81 v4.19.80 v4.19.79 v4.19.78 v4.19.77 v4.19.76 v4.19.75 v4.19.74 v4.19.73 v4.19.72 v4.19.71 v4.19.70 v4.19.69 v4.19.68 v4.19.67 v4.19.66 v4.19.65 v4.19.64 v4.19.63 v4.19.62 v4.19.61 v4.19.60 v4.19.59 v4.19.58 v4.19.57 v4.19.56 v4.19.55 v4.19.54 v4.19.53 v4.19.52 v4.19.51 v4.19.50 v4.19.49 v4.19.48 v4.19.47 v4.19.46 v4.19.45 v4.19.44 v4.19.43 v4.19.42 v4.19.41 v4.19.40 v4.19.39 v4.19.38 v4.19.37 v4.19.36 v4.19.35 v4.19.34 v4.19.33 v4.19.32 v4.19.31 v4.19.30 v4.19.29 v4.19.28 v4.19.27 v4.19.26 v4.19.25 v4.19.24 v4.19.23 v4.19.22 v4.19.21 v4.19.20 v4.19.19 v4.19.18 v4.19.17 v4.19.16 v4.19.15 v4.19.14 v4.19.13 v4.19.12 v4.19.11 v4.19.10 v4.19.9 v4.19.8 v4.19.7 v4.19.6 v4.19.5 v4.19.4 v4.19.3 v4.19.2 v4.19.1 v4.19 v4.19-rc8 v4.19-rc7 v4.19-rc6 v4.19-rc5 v4.19-rc4 v4.19-rc3 v4.19-rc2 v4.19-rc1 ck-release-21 ck-release-20 ck-release-19.2 ck-release-19.1 ck-release-19 ck-release-18 ck-release-17.2 ck-release-17.1 ck-release-17 ck-release-16 ck-release-15.1 ck-release-15 ck-release-14 ck-release-13.2 ck-release-13 ck-release-12 ck-release-11 ck-release-10 ck-release-9 ck-release-7 alk-release-15 alk-release-14 alk-release-13.2 alk-release-13 alk-release-12 alk-release-11 alk-release-10 alk-release-9 alk-release-7
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......@@ -1663,7 +1663,13 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
kfree_skb(conn->rx_skb);
skb_queue_purge(&conn->pending_rx);
flush_work(&conn->pending_rx_work);
/* We can not call flush_work(&conn->pending_rx_work) here since we
* might block if we are running on a worker from the same workqueue
* pending_rx_work is waiting on.
*/
if (work_pending(&conn->pending_rx_work))
cancel_work_sync(&conn->pending_rx_work);
l2cap_unregister_all_users(conn);
......
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