Bluetooth: Fix for ACL disconnect when pairing fails

When pairing fails hci_conn refcnt drops below zero. This cause that
ACL link is not disconnected when disconnect timeout fires.

Probably this is because l2cap_conn_del calls l2cap_chan_del for each
channel, and inside l2cap_chan_del conn is dropped. After that loop
hci_chan_del is called which also drops conn.

Anyway, as it is desrcibed in hci_core.h, it is known that refcnt
drops below 0 sometimes and it should be fine. If so, let disconnect
link when hci_conn_timeout fires and refcnt is 0 or below. This patch
does it.

This affects PTS test SM_TC_JW_BV_05_C

Logs from scenario:

[69713.706227] [6515] pair_device:
[69713.706230] [6515] hci_conn_add: hci0 dst 00:1b:dc:06:06:22
[69713.706233] [6515] hci_dev_hold: hci0 orig refcnt 8
[69713.706235] [6515] hci_conn_init_sysfs: conn ffff88021f65a000
[69713.706239] [6515] hci_req_add_ev: hci0 opcode 0x200d plen 25
[69713.706242] [6515] hci_prepare_cmd: skb len 28
[69713.706243] [6515] hci_req_run: length 1
[69713.706248] [6515] hci_conn_hold: hcon ffff88021f65a000 orig refcnt 0
[69713.706251] [6515] hci_dev_put: hci0 orig refcnt 9
[69713.706281] [8909] hci_cmd_work: hci0 cmd_cnt 1 cmd queued 1
[69713.706288] [8909] hci_send_frame: hci0 type 1 len 28
[69713.706290] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 28
[69713.706316] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.706382] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.711664] [8909] hci_rx_work: hci0
[69713.711668] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 6
[69713.711680] [8909] hci_rx_work: hci0 Event packet
[69713.711683] [8909] hci_cs_le_create_conn: hci0 status 0x00
[69713.711685] [8909] hci_sent_cmd_data: hci0 opcode 0x200d
[69713.711688] [8909] hci_req_cmd_complete: opcode 0x200d status 0x00
[69713.711690] [8909] hci_sent_cmd_data: hci0 opcode 0x200d
[69713.711695] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.711744] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.818875] [8909] hci_rx_work: hci0
[69713.818889] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 21
[69713.818913] [8909] hci_rx_work: hci0 Event packet
[69713.818917] [8909] hci_le_conn_complete_evt: hci0 status 0x00
[69713.818922] [8909] hci_send_to_control: len 19
[69713.818927] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.818938] [8909] hci_conn_add_sysfs: conn ffff88021f65a000
[69713.818975] [6450] bt_sock_poll: sock ffff88005e758500, sk ffff88010323b800
[69713.818981] [6515] hci_sock_recvmsg: sock ffff88005e75a080, sk ffff88010323ac00
...
[69713.819021] [8909] hci_dev_hold: hci0 orig refcnt 10
[69713.819025] [8909] l2cap_connect_cfm: hcon ffff88021f65a000 bdaddr 00:1b:dc:06:06:22 status 0
[69713.819028] [8909] hci_chan_create: hci0 hcon ffff88021f65a000
[69713.819031] [8909] l2cap_conn_add: hcon ffff88021f65a000 conn ffff880221005c00 hchan ffff88020d60b1c0
[69713.819034] [8909] l2cap_conn_ready: conn ffff880221005c00
[69713.819036] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.819037] [8909] smp_conn_security: conn ffff880221005c00 hcon ffff88021f65a000 level 0x02
[69713.819039] [8909] smp_chan_create:
[69713.819041] [8909] hci_conn_hold: hcon ffff88021f65a000 orig refcnt 1
[69713.819043] [8909] smp_send_cmd: code 0x01
[69713.819045] [8909] hci_send_acl: hci0 chan ffff88020d60b1c0 flags 0x0000
[69713.819046] [5949] hci_sock_recvmsg: sock ffff8800941a9900, sk ffff88012bf4e800
[69713.819049] [8909] hci_queue_acl: hci0 nonfrag skb ffff88005157c100 len 15
[69713.819055] [5949] hci_sock_recvmsg: sock ffff8800941a9900, sk ffff88012bf4e800
[69713.819057] [8909] l2cap_le_conn_ready:
[69713.819064] [8909] l2cap_chan_create: chan ffff88005ede2c00
[69713.819066] [8909] l2cap_chan_hold: chan ffff88005ede2c00 orig refcnt 1
[69713.819069] [8909] l2cap_sock_init: sk ffff88005ede5800
[69713.819072] [8909] bt_accept_enqueue: parent ffff880160356000, sk ffff88005ede5800
[69713.819074] [8909] __l2cap_chan_add: conn ffff880221005c00, psm 0x00, dcid 0x0004
[69713.819076] [8909] l2cap_chan_hold: chan ffff88005ede2c00 orig refcnt 2
[69713.819078] [8909] hci_conn_hold: hcon ffff88021f65a000 orig refcnt 2
[69713.819080] [8909] smp_conn_security: conn ffff880221005c00 hcon ffff88021f65a000 level 0x01
[69713.819082] [8909] l2cap_sock_ready_cb: sk ffff88005ede5800, parent ffff880160356000
[69713.819086] [8909] le_pairing_complete_cb: status 0
[69713.819091] [8909] hci_tx_work: hci0 acl 10 sco 8 le 0
[69713.819093] [8909] hci_sched_acl: hci0
[69713.819094] [8909] hci_sched_sco: hci0
[69713.819096] [8909] hci_sched_esco: hci0
[69713.819098] [8909] hci_sched_le: hci0
[69713.819099] [8909] hci_chan_sent: hci0
[69713.819101] [8909] hci_chan_sent: chan ffff88020d60b1c0 quote 10
[69713.819104] [8909] hci_sched_le: chan ffff88020d60b1c0 skb ffff88005157c100 len 15 priority 7
[69713.819106] [8909] hci_send_frame: hci0 type 2 len 15
[69713.819108] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 15
[69713.819119] [8909] hci_chan_sent: hci0
[69713.819121] [8909] hci_prio_recalculate: hci0
[69713.819123] [8909] process_pending_rx:
[69713.819226] [6450] hci_sock_recvmsg: sock ffff88005e758780, sk ffff88010323d400
...
[69713.822022] [6450] l2cap_sock_accept: sk ffff880160356000 timeo 0
[69713.822024] [6450] bt_accept_dequeue: parent ffff880160356000
[69713.822026] [6450] bt_accept_unlink: sk ffff88005ede5800 state 1
[69713.822028] [6450] l2cap_sock_accept: new socket ffff88005ede5800
[69713.822368] [6450] l2cap_sock_getname: sock ffff8800941ab700, sk ffff88005ede5800
[69713.822375] [6450] l2cap_sock_getsockopt: sk ffff88005ede5800
[69713.822383] [6450] l2cap_sock_getname: sock ffff8800941ab700, sk ffff88005ede5800
[69713.822414] [6450] bt_sock_poll: sock ffff8800941ab700, sk ffff88005ede5800
...
[69713.823255] [6450] l2cap_sock_getname: sock ffff8800941ab700, sk ffff88005ede5800
[69713.823259] [6450] l2cap_sock_getsockopt: sk ffff88005ede5800
[69713.824322] [6450] l2cap_sock_getname: sock ffff8800941ab700, sk ffff88005ede5800
[69713.824330] [6450] l2cap_sock_getsockopt: sk ffff88005ede5800
[69713.825029] [6450] bt_sock_poll: sock ffff88005e758500, sk ffff88010323b800
...
[69713.825187] [6450] l2cap_sock_sendmsg: sock ffff8800941ab700, sk ffff88005ede5800
[69713.825189] [6450] bt_sock_wait_ready: sk ffff88005ede5800
[69713.825192] [6450] l2cap_create_basic_pdu: chan ffff88005ede2c00 len 3
[69713.825196] [6450] l2cap_do_send: chan ffff88005ede2c00, skb ffff880160b0b500 len 7 priority 0
[69713.825199] [6450] hci_send_acl: hci0 chan ffff88020d60b1c0 flags 0x0000
[69713.825201] [6450] hci_queue_acl: hci0 nonfrag skb ffff880160b0b500 len 11
[69713.825210] [8909] hci_tx_work: hci0 acl 9 sco 8 le 0
[69713.825213] [8909] hci_sched_acl: hci0
[69713.825214] [8909] hci_sched_sco: hci0
[69713.825216] [8909] hci_sched_esco: hci0
[69713.825217] [8909] hci_sched_le: hci0
[69713.825219] [8909] hci_chan_sent: hci0
[69713.825221] [8909] hci_chan_sent: chan ffff88020d60b1c0 quote 9
[69713.825223] [8909] hci_sched_le: chan ffff88020d60b1c0 skb ffff880160b0b500 len 11 priority 0
[69713.825225] [8909] hci_send_frame: hci0 type 2 len 11
[69713.825227] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 11
[69713.825242] [8909] hci_chan_sent: hci0
[69713.825253] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.825253] [8909] hci_prio_recalculate: hci0
[69713.825292] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.825768] [6450] bt_sock_poll: sock ffff88005e758500, sk ffff88010323b800
...
[69713.866902] [8909] hci_rx_work: hci0
[69713.866921] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 7
[69713.866928] [8909] hci_rx_work: hci0 Event packet
[69713.866931] [8909] hci_num_comp_pkts_evt: hci0 num_hndl 1
[69713.866937] [8909] hci_tx_work: hci0 acl 9 sco 8 le 0
[69713.866939] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.866940] [8909] hci_sched_acl: hci0
...
[69713.866944] [8909] hci_sched_le: hci0
[69713.866953] [8909] hci_chan_sent: hci0
[69713.866997] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.867840] [28074] hci_rx_work: hci0
[69713.867844] [28074] hci_send_to_monitor: hdev ffff88021f0c7000 len 7
[69713.867850] [28074] hci_rx_work: hci0 Event packet
[69713.867853] [28074] hci_num_comp_pkts_evt: hci0 num_hndl 1
[69713.867857] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69713.867858] [28074] hci_tx_work: hci0 acl 10 sco 8 le 0
[69713.867860] [28074] hci_sched_acl: hci0
[69713.867861] [28074] hci_sched_sco: hci0
[69713.867862] [28074] hci_sched_esco: hci0
[69713.867863] [28074] hci_sched_le: hci0
[69713.867865] [28074] hci_chan_sent: hci0
[69713.867888] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69714.145661] [8909] hci_rx_work: hci0
[69714.145666] [8909] hci_send_to_monitor: hdev ffff88021f0c7000 len 10
[69714.145676] [8909] hci_rx_work: hci0 ACL data packet
[69714.145679] [8909] hci_acldata_packet: hci0 len 6 handle 0x002d flags 0x0002
[69714.145681] [8909] hci_conn_enter_active_mode: hcon ffff88021f65a000 mode 0
[69714.145683] [8909] l2cap_recv_acldata: conn ffff880221005c00 len 6 flags 0x2
[69714.145693] [8909] l2cap_recv_frame: len 2, cid 0x0006
[69714.145696] [8909] hci_send_to_control: len 14
[69714.145710] [8909] smp_chan_destroy:
[69714.145713] [8909] pairing_complete: status 3
[69714.145714] [8909] cmd_complete: sock ffff88010323ac00
[69714.145717] [8909] hci_conn_drop: hcon ffff88021f65a000 orig refcnt 3
[69714.145719] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69714.145720] [6450] bt_sock_poll: sock ffff88005e758500, sk ffff88010323b800
[69714.145722] [6515] hci_sock_recvmsg: sock ffff88005e75a080, sk ffff88010323ac00
[69714.145724] [6450] bt_sock_poll: sock ffff8801db6b4f00, sk ffff880160351c00
...
[69714.145735] [6515] hci_sock_recvmsg: sock ffff88005e75a080, sk ffff88010323ac00
[69714.145737] [8909] hci_conn_drop: hcon ffff88021f65a000 orig refcnt 2
[69714.145739] [8909] l2cap_conn_del: hcon ffff88021f65a000 conn ffff880221005c00, err 13
[69714.145740] [6450] bt_sock_poll: sock ffff8801db6b5400, sk ffff88021e775000
[69714.145743] [6450] bt_sock_poll: sock ffff8801db6b5e00, sk ffff880160356000
[69714.145744] [8909] l2cap_chan_hold: chan ffff88005ede2c00 orig refcnt 3
[69714.145746] [6450] bt_sock_poll: sock ffff8800941ab700, sk ffff88005ede5800
[69714.145748] [8909] l2cap_chan_del: chan ffff88005ede2c00, conn ffff880221005c00, err 13
[69714.145749] [8909] l2cap_chan_put: chan ffff88005ede2c00 orig refcnt 4
[69714.145751] [8909] hci_conn_drop: hcon ffff88021f65a000 orig refcnt 1
[69714.145754] [6450] bt_sock_poll: sock ffff8800941ab700, sk ffff88005ede5800
[69714.145756] [8909] l2cap_chan_put: chan ffff88005ede2c00 orig refcnt 3
[69714.145759] [8909] hci_chan_del: hci0 hcon ffff88021f65a000 chan ffff88020d60b1c0
[69714.145766] [5949] hci_sock_recvmsg: sock ffff8800941a9680, sk ffff88012bf4d000
[69714.145787] [6515] hci_sock_release: sock ffff88005e75a080 sk ffff88010323ac00
[69714.146002] [6450] hci_sock_recvmsg: sock ffff88005e758780, sk ffff88010323d400
[69714.150795] [6450] l2cap_sock_release: sock ffff8800941ab700, sk ffff88005ede5800
[69714.150799] [6450] l2cap_sock_shutdown: sock ffff8800941ab700, sk ffff88005ede5800
[69714.150802] [6450] l2cap_chan_close: chan ffff88005ede2c00 state BT_CLOSED
[69714.150805] [6450] l2cap_sock_kill: sk ffff88005ede5800 state BT_CLOSED
[69714.150806] [6450] l2cap_chan_put: chan ffff88005ede2c00 orig refcnt 2
[69714.150808] [6450] l2cap_sock_destruct: sk ffff88005ede5800
[69714.150809] [6450] l2cap_chan_put: chan ffff88005ede2c00 orig refcnt 1
[69714.150811] [6450] l2cap_chan_destroy: chan ffff88005ede2c00
[69714.150970] [6450] bt_sock_poll: sock ffff88005e758500, sk ffff88010323b800
...
[69714.151991] [8909] hci_conn_drop: hcon ffff88021f65a000 orig refcnt 0
[69716.150339] [8909] hci_conn_timeout: hcon ffff88021f65a000 state BT_CONNECTED, refcnt -1

Signed-off-by: Lukasz Rymanowski <lukasz.rymanowski@tieto.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index ca01d18..a7a27bc 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -289,10 +289,20 @@ static void hci_conn_timeout(struct work_struct *work)
 {
 	struct hci_conn *conn = container_of(work, struct hci_conn,
 					     disc_work.work);
+	int refcnt = atomic_read(&conn->refcnt);
 
 	BT_DBG("hcon %p state %s", conn, state_to_string(conn->state));
 
-	if (atomic_read(&conn->refcnt))
+	WARN_ON(refcnt < 0);
+
+	/* FIXME: It was observed that in pairing failed scenario, refcnt
+	 * drops below 0. Probably this is because l2cap_conn_del calls
+	 * l2cap_chan_del for each channel, and inside l2cap_chan_del conn is
+	 * dropped. After that loop hci_chan_del is called which also drops
+	 * conn. For now make sure that ACL is alive if refcnt is higher then 0,
+	 * otherwise drop it.
+	 */
+	if (refcnt > 0)
 		return;
 
 	switch (conn->state) {