2023-01-10 21:35:34

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: [PATCH] Bluetooth: ISO: Fix possible circular locking dependency

From: Luiz Augusto von Dentz <[email protected]>

This attempts to fix the following trace:

kworker/u3:1/184 is trying to acquire lock:
ffff888001888130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at:
iso_connect_cfm+0x2de/0x690

but task is already holding lock:
ffff8880028d1c20 (&conn->lock){+.+.}-{2:2}, at:
iso_connect_cfm+0x265/0x690

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&conn->lock){+.+.}-{2:2}:
lock_acquire+0x176/0x3d0
_raw_spin_lock+0x2a/0x40
__iso_sock_close+0x1dd/0x4f0
iso_sock_release+0xa0/0x1b0
sock_close+0x5e/0x120
__fput+0x102/0x410
task_work_run+0xf1/0x160
exit_to_user_mode_prepare+0x170/0x180
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x4e/0x90
entry_SYSCALL_64_after_hwframe+0x62/0xcc

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
check_prev_add+0xfc/0x1190
__lock_acquire+0x1e27/0x2750
lock_acquire+0x176/0x3d0
lock_sock_nested+0x32/0x80
iso_connect_cfm+0x2de/0x690
hci_cc_le_setup_iso_path+0x195/0x340
hci_cmd_complete_evt+0x1ae/0x500
hci_event_packet+0x38e/0x7c0
hci_rx_work+0x34c/0x980
process_one_work+0x5a5/0x9a0
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x22/0x30

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&conn->lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
lock(&conn->lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);

*** DEADLOCK ***

Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type")
Fixes: f764a6c2c1e4 ("Bluetooth: ISO: Add broadcast support")
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
net/bluetooth/iso.c | 61 +++++++++++++++++++--------------------------
1 file changed, 26 insertions(+), 35 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 035bb5d25f85..6157bc12b373 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -289,15 +289,15 @@ static int iso_connect_bis(struct sock *sk)
hci_dev_unlock(hdev);
hci_dev_put(hdev);

+ err = iso_chan_add(conn, sk, NULL);
+ if (err)
+ return err;
+
lock_sock(sk);

/* Update source addr of the socket */
bacpy(&iso_pi(sk)->src, &hcon->src);

- err = iso_chan_add(conn, sk, NULL);
- if (err)
- goto release;
-
if (hcon->state == BT_CONNECTED) {
iso_sock_clear_timer(sk);
sk->sk_state = BT_CONNECTED;
@@ -306,7 +306,6 @@ static int iso_connect_bis(struct sock *sk)
iso_sock_set_timer(sk, sk->sk_sndtimeo);
}

-release:
release_sock(sk);
return err;

@@ -372,15 +371,15 @@ static int iso_connect_cis(struct sock *sk)
hci_dev_unlock(hdev);
hci_dev_put(hdev);

+ err = iso_chan_add(conn, sk, NULL);
+ if (err)
+ return err;
+
lock_sock(sk);

/* Update source addr of the socket */
bacpy(&iso_pi(sk)->src, &hcon->src);

- err = iso_chan_add(conn, sk, NULL);
- if (err)
- goto release;
-
if (hcon->state == BT_CONNECTED) {
iso_sock_clear_timer(sk);
sk->sk_state = BT_CONNECTED;
@@ -392,7 +391,6 @@ static int iso_connect_cis(struct sock *sk)
iso_sock_set_timer(sk, sk->sk_sndtimeo);
}

-release:
release_sock(sk);
return err;

@@ -1432,33 +1430,29 @@ static void iso_conn_ready(struct iso_conn *conn)
struct sock *parent;
struct sock *sk = conn->sk;
struct hci_ev_le_big_sync_estabilished *ev;
+ struct hci_conn *hcon;

BT_DBG("conn %p", conn);

if (sk) {
iso_sock_ready(conn->sk);
} else {
- iso_conn_lock(conn);
-
- if (!conn->hcon) {
- iso_conn_unlock(conn);
+ hcon = conn->hcon;
+ if (!hcon)
return;
- }

- ev = hci_recv_event_data(conn->hcon->hdev,
+ ev = hci_recv_event_data(hcon->hdev,
HCI_EVT_LE_BIG_SYNC_ESTABILISHED);
if (ev)
- parent = iso_get_sock_listen(&conn->hcon->src,
- &conn->hcon->dst,
+ parent = iso_get_sock_listen(&hcon->src,
+ &hcon->dst,
iso_match_big, ev);
else
- parent = iso_get_sock_listen(&conn->hcon->src,
+ parent = iso_get_sock_listen(&hcon->src,
BDADDR_ANY, NULL, NULL);

- if (!parent) {
- iso_conn_unlock(conn);
+ if (!parent)
return;
- }

lock_sock(parent);

@@ -1466,30 +1460,29 @@ static void iso_conn_ready(struct iso_conn *conn)
BTPROTO_ISO, GFP_ATOMIC, 0);
if (!sk) {
release_sock(parent);
- iso_conn_unlock(conn);
return;
}

iso_sock_init(sk, parent);

- bacpy(&iso_pi(sk)->src, &conn->hcon->src);
- iso_pi(sk)->src_type = conn->hcon->src_type;
+ bacpy(&iso_pi(sk)->src, &hcon->src);
+ iso_pi(sk)->src_type = hcon->src_type;

/* If hcon has no destination address (BDADDR_ANY) it means it
* was created by HCI_EV_LE_BIG_SYNC_ESTABILISHED so we need to
* initialize using the parent socket destination address.
*/
- if (!bacmp(&conn->hcon->dst, BDADDR_ANY)) {
- bacpy(&conn->hcon->dst, &iso_pi(parent)->dst);
- conn->hcon->dst_type = iso_pi(parent)->dst_type;
- conn->hcon->sync_handle = iso_pi(parent)->sync_handle;
+ if (!bacmp(&hcon->dst, BDADDR_ANY)) {
+ bacpy(&hcon->dst, &iso_pi(parent)->dst);
+ hcon->dst_type = iso_pi(parent)->dst_type;
+ hcon->sync_handle = iso_pi(parent)->sync_handle;
}

- bacpy(&iso_pi(sk)->dst, &conn->hcon->dst);
- iso_pi(sk)->dst_type = conn->hcon->dst_type;
+ bacpy(&iso_pi(sk)->dst, &hcon->dst);
+ iso_pi(sk)->dst_type = hcon->dst_type;

- hci_conn_hold(conn->hcon);
- __iso_chan_add(conn, sk, parent);
+ hci_conn_hold(hcon);
+ iso_chan_add(conn, sk, parent);

if (test_bit(BT_SK_DEFER_SETUP, &bt_sk(parent)->flags))
sk->sk_state = BT_CONNECT2;
@@ -1500,8 +1493,6 @@ static void iso_conn_ready(struct iso_conn *conn)
parent->sk_data_ready(parent);

release_sock(parent);
-
- iso_conn_unlock(conn);
}
}

--
2.37.3


2023-01-10 22:01:58

by bluez.test.bot

[permalink] [raw]
Subject: RE: Bluetooth: ISO: Fix possible circular locking dependency

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=710698

---Test result---

Test Summary:
CheckPatch PASS 0.90 seconds
GitLint PASS 0.32 seconds
SubjectPrefix PASS 0.09 seconds
BuildKernel PASS 31.83 seconds
CheckAllWarning PASS 35.21 seconds
CheckSparse PASS 39.26 seconds
CheckSmatch PASS 107.05 seconds
BuildKernel32 PASS 30.59 seconds
TestRunnerSetup PASS 441.39 seconds
TestRunner_l2cap-tester PASS 16.59 seconds
TestRunner_iso-tester PASS 17.17 seconds
TestRunner_bnep-tester PASS 5.83 seconds
TestRunner_mgmt-tester PASS 111.56 seconds
TestRunner_rfcomm-tester PASS 9.17 seconds
TestRunner_sco-tester PASS 8.40 seconds
TestRunner_ioctl-tester PASS 9.85 seconds
TestRunner_mesh-tester PASS 7.22 seconds
TestRunner_smp-tester PASS 8.31 seconds
TestRunner_userchan-tester PASS 6.11 seconds
IncrementalBuild PASS 29.04 seconds



---
Regards,
Linux Bluetooth