Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put
This fixes the following trace which is caused by hci_rx_work starting up *after* the final channel reference has been put() during sock_close() but *before* the references to the channel have been destroyed, so instead the code now rely on kref_get_unless_zero/l2cap_chan_hold_unless_zero to prevent referencing a channel that is about to be destroyed. refcount_t: increment on 0; use-after-free. BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0 Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705 CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S W 4.14.234-00003-g1fb6d0bd49a4-dirty #28 Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT) Workqueue: hci0 hci_rx_work Call trace: dump_backtrace+0x0/0x378 show_stack+0x20/0x2c dump_stack+0x124/0x148 print_address_description+0x80/0x2e8 __kasan_report+0x168/0x188 kasan_report+0x10/0x18 __asan_load4+0x84/0x8c refcount_dec_and_test+0x20/0xd0 l2cap_chan_put+0x48/0x12c l2cap_recv_frame+0x4770/0x6550 l2cap_recv_acldata+0x44c/0x7a4 hci_acldata_packet+0x100/0x188 hci_rx_work+0x178/0x23c process_one_work+0x35c/0x95c worker_thread+0x4cc/0x960 kthread+0x1a8/0x1c4 ret_from_fork+0x10/0x18 Cc: stable@kernel.org Reported-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Tested-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Luiz Augusto von Dentz
parent
ef61b6ea15
commit
d0be8347c6
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@ -847,6 +847,7 @@ enum {
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};
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void l2cap_chan_hold(struct l2cap_chan *c);
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struct l2cap_chan *l2cap_chan_hold_unless_zero(struct l2cap_chan *c);
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void l2cap_chan_put(struct l2cap_chan *c);
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static inline void l2cap_chan_lock(struct l2cap_chan *chan)
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@ -111,7 +111,8 @@ static struct l2cap_chan *__l2cap_get_chan_by_scid(struct l2cap_conn *conn,
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}
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/* Find channel with given SCID.
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* Returns locked channel. */
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* Returns a reference locked channel.
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*/
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static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn,
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u16 cid)
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{
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@ -119,15 +120,19 @@ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn,
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mutex_lock(&conn->chan_lock);
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c = __l2cap_get_chan_by_scid(conn, cid);
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if (c)
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l2cap_chan_lock(c);
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if (c) {
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/* Only lock if chan reference is not 0 */
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c = l2cap_chan_hold_unless_zero(c);
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if (c)
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l2cap_chan_lock(c);
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}
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mutex_unlock(&conn->chan_lock);
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return c;
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}
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/* Find channel with given DCID.
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* Returns locked channel.
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* Returns a reference locked channel.
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*/
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static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn,
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u16 cid)
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@ -136,8 +141,12 @@ static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn,
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mutex_lock(&conn->chan_lock);
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c = __l2cap_get_chan_by_dcid(conn, cid);
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if (c)
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l2cap_chan_lock(c);
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if (c) {
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/* Only lock if chan reference is not 0 */
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c = l2cap_chan_hold_unless_zero(c);
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if (c)
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l2cap_chan_lock(c);
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}
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mutex_unlock(&conn->chan_lock);
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return c;
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@ -162,8 +171,12 @@ static struct l2cap_chan *l2cap_get_chan_by_ident(struct l2cap_conn *conn,
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mutex_lock(&conn->chan_lock);
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c = __l2cap_get_chan_by_ident(conn, ident);
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if (c)
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l2cap_chan_lock(c);
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if (c) {
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/* Only lock if chan reference is not 0 */
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c = l2cap_chan_hold_unless_zero(c);
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if (c)
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l2cap_chan_lock(c);
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}
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mutex_unlock(&conn->chan_lock);
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return c;
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@ -497,6 +510,16 @@ void l2cap_chan_hold(struct l2cap_chan *c)
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kref_get(&c->kref);
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}
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struct l2cap_chan *l2cap_chan_hold_unless_zero(struct l2cap_chan *c)
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{
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BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
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if (!kref_get_unless_zero(&c->kref))
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return NULL;
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return c;
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}
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void l2cap_chan_put(struct l2cap_chan *c)
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{
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BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
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@ -1968,7 +1991,10 @@ static struct l2cap_chan *l2cap_global_chan_by_psm(int state, __le16 psm,
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src_match = !bacmp(&c->src, src);
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dst_match = !bacmp(&c->dst, dst);
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if (src_match && dst_match) {
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l2cap_chan_hold(c);
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c = l2cap_chan_hold_unless_zero(c);
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if (!c)
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continue;
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read_unlock(&chan_list_lock);
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return c;
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}
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@ -1983,7 +2009,7 @@ static struct l2cap_chan *l2cap_global_chan_by_psm(int state, __le16 psm,
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}
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if (c1)
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l2cap_chan_hold(c1);
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c1 = l2cap_chan_hold_unless_zero(c1);
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read_unlock(&chan_list_lock);
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@ -4463,6 +4489,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn,
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unlock:
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return err;
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}
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@ -4577,6 +4604,7 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn,
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done:
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return err;
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}
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@ -5304,6 +5332,7 @@ static inline int l2cap_move_channel_req(struct l2cap_conn *conn,
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l2cap_send_move_chan_rsp(chan, result);
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return 0;
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}
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@ -5396,6 +5425,7 @@ static void l2cap_move_continue(struct l2cap_conn *conn, u16 icid, u16 result)
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}
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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}
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static void l2cap_move_fail(struct l2cap_conn *conn, u8 ident, u16 icid,
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@ -5425,6 +5455,7 @@ static void l2cap_move_fail(struct l2cap_conn *conn, u8 ident, u16 icid,
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l2cap_send_move_chan_cfm(chan, L2CAP_MC_UNCONFIRMED);
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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}
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static int l2cap_move_channel_rsp(struct l2cap_conn *conn,
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@ -5488,6 +5519,7 @@ static int l2cap_move_channel_confirm(struct l2cap_conn *conn,
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l2cap_send_move_chan_cfm_rsp(conn, cmd->ident, icid);
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return 0;
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}
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@ -5523,6 +5555,7 @@ static inline int l2cap_move_channel_confirm_rsp(struct l2cap_conn *conn,
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}
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return 0;
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}
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@ -5895,12 +5928,11 @@ static inline int l2cap_le_credits(struct l2cap_conn *conn,
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if (credits > max_credits) {
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BT_ERR("LE credits overflow");
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l2cap_send_disconn_req(chan, ECONNRESET);
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l2cap_chan_unlock(chan);
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/* Return 0 so that we don't trigger an unnecessary
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* command reject packet.
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*/
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return 0;
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goto unlock;
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}
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chan->tx_credits += credits;
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@ -5911,7 +5943,9 @@ static inline int l2cap_le_credits(struct l2cap_conn *conn,
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if (chan->tx_credits)
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chan->ops->resume(chan);
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unlock:
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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return 0;
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}
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@ -7597,6 +7631,7 @@ static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid,
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done:
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l2cap_chan_unlock(chan);
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l2cap_chan_put(chan);
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}
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static void l2cap_conless_channel(struct l2cap_conn *conn, __le16 psm,
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@ -8085,7 +8120,7 @@ static struct l2cap_chan *l2cap_global_fixed_chan(struct l2cap_chan *c,
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if (src_type != c->src_type)
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continue;
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l2cap_chan_hold(c);
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c = l2cap_chan_hold_unless_zero(c);
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read_unlock(&chan_list_lock);
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return c;
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}
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