diff mbox series

[1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

Message ID 20230330220332.1035910-2-luiz.dentz@gmail.com (mailing list archive)
State Accepted
Commit 53fd49a194f611cb7b5af5edcdd07a3ecfac983f
Headers show
Series [1/2] Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm | expand

Checks

Context Check Description
tedd_an/pre-ci_am success Success
tedd_an/CheckPatch success CheckPatch PASS
tedd_an/GitLint fail 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"
tedd_an/SubjectPrefix success Gitlint PASS
tedd_an/BuildKernel success BuildKernel PASS
tedd_an/CheckAllWarning success CheckAllWarning PASS
tedd_an/CheckSparse warning CheckSparse WARNING net/bluetooth/sco.c: note: in included file:./include/net/bluetooth/hci_core.h:149:35: warning: array of flexible structures
tedd_an/CheckSmatch warning CheckSparse WARNING net/bluetooth/sco.c: note: in included file:./include/net/bluetooth/hci_core.h:149:35: warning: array of flexible structures
tedd_an/BuildKernel32 success BuildKernel32 PASS
tedd_an/TestRunnerSetup success TestRunnerSetup PASS
tedd_an/TestRunner_l2cap-tester success TestRunner PASS
tedd_an/TestRunner_iso-tester success TestRunner PASS
tedd_an/TestRunner_bnep-tester success TestRunner PASS
tedd_an/TestRunner_mgmt-tester success TestRunner PASS
tedd_an/TestRunner_rfcomm-tester success TestRunner PASS
tedd_an/TestRunner_sco-tester success TestRunner PASS
tedd_an/TestRunner_ioctl-tester success TestRunner PASS
tedd_an/TestRunner_mesh-tester success TestRunner PASS
tedd_an/TestRunner_smp-tester success TestRunner PASS
tedd_an/TestRunner_userchan-tester success TestRunner PASS
tedd_an/IncrementalBuild success Incremental Build PASS

Commit Message

Luiz Augusto von Dentz March 30, 2023, 10:03 p.m. UTC 
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

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 <luiz.von.dentz@intel.com>
---
 net/bluetooth/sco.c | 69 ++++++++++++++++++++++++++-------------------
 1 file changed, 40 insertions(+), 29 deletions(-)

Comments

bluez.test.bot@gmail.com March 30, 2023, 10:35 p.m. UTC | #1 
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
patchwork-bot+bluetooth@kernel.org March 31, 2023, 10:10 p.m. UTC | #2 
Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Thu, 30 Mar 2023 15:03:31 -0700 you wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> 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!
diff mbox series

Patch

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;
 }