2023-03-30 22:09:04

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: [PATCH 1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

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

This attempts to fix the following trace:

======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-g0b93eeba4454 #4703 Not tainted
------------------------------------------------------
kworker/u3:0/46 is trying to acquire lock:
ffff888001fd9130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
sco_connect_cfm+0x118/0x4a0

but task is already holding lock:
ffffffff831e3340 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_sync_conn_complete_evt+0x1ad/0x3d0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
__mutex_lock+0x13b/0xcc0
hci_sync_conn_complete_evt+0x1ad/0x3d0
hci_event_packet+0x55c/0x7c0
hci_rx_work+0x34c/0xa00
process_one_work+0x575/0x910
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x2b/0x50

-> #1 (&hdev->lock){+.+.}-{3:3}:
__mutex_lock+0x13b/0xcc0
sco_sock_connect+0xfc/0x630
__sys_connect+0x197/0x1b0
__x64_sys_connect+0x37/0x50
do_syscall_64+0x42/0x90
entry_SYSCALL_64_after_hwframe+0x70/0xda

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
__lock_acquire+0x18cc/0x3740
lock_acquire+0x151/0x3a0
lock_sock_nested+0x32/0x80
sco_connect_cfm+0x118/0x4a0
hci_sync_conn_complete_evt+0x1e6/0x3d0
hci_event_packet+0x55c/0x7c0
hci_rx_work+0x34c/0xa00
process_one_work+0x575/0x910
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x2b/0x50

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

4 locks held by kworker/u3:0/46:
#0: ffff8880028d1130 ((wq_completion)hci0#2){+.+.}-{0:0}, at:
process_one_work+0x4c0/0x910
#1: ffff8880013dfde0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0},
at: process_one_work+0x4c0/0x910
#2: ffff8880025d8070 (&hdev->lock){+.+.}-{3:3}, at:
hci_sync_conn_complete_evt+0xa6/0x3d0
#3: ffffffffb79e3340 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_sync_conn_complete_evt+0x1ad/0x3d0

Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
net/bluetooth/sco.c | 69 ++++++++++++++++++++++++++-------------------
1 file changed, 40 insertions(+), 29 deletions(-)

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 1111da4e2f2b..f3a5ab9e4fa4 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -235,27 +235,41 @@ static int sco_chan_add(struct sco_conn *conn, struct sock *sk,
return err;
}

-static int sco_connect(struct hci_dev *hdev, struct sock *sk)
+static int sco_connect(struct sock *sk)
{
struct sco_conn *conn;
struct hci_conn *hcon;
+ struct hci_dev *hdev;
int err, type;

BT_DBG("%pMR -> %pMR", &sco_pi(sk)->src, &sco_pi(sk)->dst);

+ hdev = hci_get_route(&sco_pi(sk)->dst, &sco_pi(sk)->src, BDADDR_BREDR);
+ if (!hdev)
+ return -EHOSTUNREACH;
+
+ hci_dev_lock(hdev);
+
if (lmp_esco_capable(hdev) && !disable_esco)
type = ESCO_LINK;
else
type = SCO_LINK;

if (sco_pi(sk)->setting == BT_VOICE_TRANSPARENT &&
- (!lmp_transp_capable(hdev) || !lmp_esco_capable(hdev)))
- return -EOPNOTSUPP;
+ (!lmp_transp_capable(hdev) || !lmp_esco_capable(hdev))) {
+ err = -EOPNOTSUPP;
+ goto unlock;
+ }

hcon = hci_connect_sco(hdev, type, &sco_pi(sk)->dst,
sco_pi(sk)->setting, &sco_pi(sk)->codec);
- if (IS_ERR(hcon))
- return PTR_ERR(hcon);
+ if (IS_ERR(hcon)) {
+ err = PTR_ERR(hcon);
+ goto unlock;
+ }
+
+ hci_dev_unlock(hdev);
+ hci_dev_put(hdev);

conn = sco_conn_add(hcon);
if (!conn) {
@@ -263,13 +277,15 @@ static int sco_connect(struct hci_dev *hdev, struct sock *sk)
return -ENOMEM;
}

- /* Update source addr of the socket */
- bacpy(&sco_pi(sk)->src, &hcon->src);
-
err = sco_chan_add(conn, sk, NULL);
if (err)
return err;

+ lock_sock(sk);
+
+ /* Update source addr of the socket */
+ bacpy(&sco_pi(sk)->src, &hcon->src);
+
if (hcon->state == BT_CONNECTED) {
sco_sock_clear_timer(sk);
sk->sk_state = BT_CONNECTED;
@@ -278,6 +294,13 @@ static int sco_connect(struct hci_dev *hdev, struct sock *sk)
sco_sock_set_timer(sk, sk->sk_sndtimeo);
}

+ release_sock(sk);
+
+ return err;
+
+unlock:
+ hci_dev_unlock(hdev);
+ hci_dev_put(hdev);
return err;
}

@@ -565,7 +588,6 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen
{
struct sockaddr_sco *sa = (struct sockaddr_sco *) addr;
struct sock *sk = sock->sk;
- struct hci_dev *hdev;
int err;

BT_DBG("sk %p", sk);
@@ -574,37 +596,26 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen
addr->sa_family != AF_BLUETOOTH)
return -EINVAL;

- lock_sock(sk);
- if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) {
- err = -EBADFD;
- goto done;
- }
+ if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND)
+ return -EBADFD;

- if (sk->sk_type != SOCK_SEQPACKET) {
+ if (sk->sk_type != SOCK_SEQPACKET)
err = -EINVAL;
- goto done;
- }
-
- hdev = hci_get_route(&sa->sco_bdaddr, &sco_pi(sk)->src, BDADDR_BREDR);
- if (!hdev) {
- err = -EHOSTUNREACH;
- goto done;
- }
- hci_dev_lock(hdev);

+ lock_sock(sk);
/* Set destination address and psm */
bacpy(&sco_pi(sk)->dst, &sa->sco_bdaddr);
+ release_sock(sk);

- err = sco_connect(hdev, sk);
- hci_dev_unlock(hdev);
- hci_dev_put(hdev);
+ err = sco_connect(sk);
if (err)
- goto done;
+ return err;
+
+ lock_sock(sk);

err = bt_sock_wait_state(sk, BT_CONNECTED,
sock_sndtimeo(sk, flags & O_NONBLOCK));

-done:
release_sock(sk);
return err;
}
--
2.39.2


2023-03-30 22:40:56

by bluez.test.bot

[permalink] [raw]
Subject: RE: [1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

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=735600

---Test result---

Test Summary:
CheckPatch PASS 0.65 seconds
GitLint FAIL 0.60 seconds
SubjectPrefix PASS 0.06 seconds
BuildKernel PASS 37.70 seconds
CheckAllWarning PASS 40.95 seconds
CheckSparse WARNING 45.92 seconds
CheckSmatch WARNING 125.20 seconds
BuildKernel32 PASS 36.44 seconds
TestRunnerSetup PASS 513.59 seconds
TestRunner_l2cap-tester PASS 17.98 seconds
TestRunner_iso-tester PASS 18.34 seconds
TestRunner_bnep-tester PASS 6.32 seconds
TestRunner_mgmt-tester PASS 121.86 seconds
TestRunner_rfcomm-tester PASS 9.78 seconds
TestRunner_sco-tester PASS 8.97 seconds
TestRunner_ioctl-tester PASS 10.44 seconds
TestRunner_mesh-tester PASS 7.75 seconds
TestRunner_smp-tester PASS 8.86 seconds
TestRunner_userchan-tester PASS 6.47 seconds
IncrementalBuild PASS 34.31 seconds

Details
##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
[1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
1: T1 Title exceeds max length (81>80): "[1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm"
##############################
Test: CheckSparse - WARNING
Desc: Run sparse tool with linux kernel
Output:
net/bluetooth/sco.c: note: in included file:./include/net/bluetooth/hci_core.h:149:35: warning: array of flexible structures
##############################
Test: CheckSmatch - WARNING
Desc: Run smatch tool with source
Output:
net/bluetooth/sco.c: note: in included file:./include/net/bluetooth/hci_core.h:149:35: warning: array of flexible structures


---
Regards,
Linux Bluetooth

2023-03-31 22:15:07

by patchwork-bot+bluetooth

[permalink] [raw]
Subject: Re: [PATCH 1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[email protected]>:

On Thu, 30 Mar 2023 15:03:31 -0700 you wrote:
> From: Luiz Augusto von Dentz <[email protected]>
>
> This attempts to fix the following trace:
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.3.0-rc2-g0b93eeba4454 #4703 Not tainted
>
> [...]

Here is the summary with links:
- [1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm
https://git.kernel.org/bluetooth/bluetooth-next/c/53fd49a194f6

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html