6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
commit f1a8f402f13f94263cf349216c257b2985100927 upstream.
This fixes the following deadlock introduced by 39a92a55be13
("bluetooth/l2cap: sync sock recv cb and release")
============================================
WARNING: possible recursive locking detected
6.10.0-rc3-g4029dba6b6f1 #6823 Not tainted
--------------------------------------------
kworker/u5:0/35 is trying to acquire lock:
ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_sock_recv_cb+0x44/0x1e0
but task is already holding lock:
ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_get_chan_by_scid+0xaf/0xd0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&chan->lock#2/1);
lock(&chan->lock#2/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by kworker/u5:0/35:
#0: ffff888002b8a940 ((wq_completion)hci0#2){+.+.}-{0:0}, at:
process_one_work+0x750/0x930
#1: ffff888002c67dd0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0},
at: process_one_work+0x44e/0x930
#2: ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_get_chan_by_scid+0xaf/0xd0
To fix the original problem this introduces l2cap_chan_lock at
l2cap_conless_channel to ensure that l2cap_sock_recv_cb is called with
chan->lock held.
Fixes: 89e856e124f9 ("bluetooth/l2cap: sync sock recv cb and release")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/bluetooth/hci_sync.h | 2 +
net/bluetooth/hci_core.c | 72 +++++++++------------------------------
net/bluetooth/hci_sync.c | 13 +++++++
net/bluetooth/l2cap_core.c | 3 +
net/bluetooth/l2cap_sock.c | 13 -------
5 files changed, 37 insertions(+), 66 deletions(-)
--- a/include/net/bluetooth/hci_sync.h
+++ b/include/net/bluetooth/hci_sync.h
@@ -38,6 +38,8 @@ int __hci_cmd_sync_status(struct hci_dev
int __hci_cmd_sync_status_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
const void *param, u8 event, u32 timeout,
struct sock *sk);
+int hci_cmd_sync_status(struct hci_dev *hdev, u16 opcode, u32 plen,
+ const void *param, u32 timeout);
void hci_cmd_sync_init(struct hci_dev *hdev);
void hci_cmd_sync_clear(struct hci_dev *hdev);
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -63,50 +63,6 @@ DEFINE_MUTEX(hci_cb_list_lock);
/* HCI ID Numbering */
static DEFINE_IDA(hci_index_ida);
-static int hci_scan_req(struct hci_request *req, unsigned long opt)
-{
- __u8 scan = opt;
-
- BT_DBG("%s %x", req->hdev->name, scan);
-
- /* Inquiry and Page scans */
- hci_req_add(req, HCI_OP_WRITE_SCAN_ENABLE, 1, &scan);
- return 0;
-}
-
-static int hci_auth_req(struct hci_request *req, unsigned long opt)
-{
- __u8 auth = opt;
-
- BT_DBG("%s %x", req->hdev->name, auth);
-
- /* Authentication */
- hci_req_add(req, HCI_OP_WRITE_AUTH_ENABLE, 1, &auth);
- return 0;
-}
-
-static int hci_encrypt_req(struct hci_request *req, unsigned long opt)
-{
- __u8 encrypt = opt;
-
- BT_DBG("%s %x", req->hdev->name, encrypt);
-
- /* Encryption */
- hci_req_add(req, HCI_OP_WRITE_ENCRYPT_MODE, 1, &encrypt);
- return 0;
-}
-
-static int hci_linkpol_req(struct hci_request *req, unsigned long opt)
-{
- __le16 policy = cpu_to_le16(opt);
-
- BT_DBG("%s %x", req->hdev->name, policy);
-
- /* Default link policy */
- hci_req_add(req, HCI_OP_WRITE_DEF_LINK_POLICY, 2, &policy);
- return 0;
-}
-
/* Get HCI device by index.
* Device is held on return. */
struct hci_dev *hci_dev_get(int index)
@@ -728,6 +684,7 @@ int hci_dev_cmd(unsigned int cmd, void _
{
struct hci_dev *hdev;
struct hci_dev_req dr;
+ __le16 policy;
int err = 0;
if (copy_from_user(&dr, arg, sizeof(dr)))
@@ -754,8 +711,8 @@ int hci_dev_cmd(unsigned int cmd, void _
switch (cmd) {
case HCISETAUTH:
- err = hci_req_sync(hdev, hci_auth_req, dr.dev_opt,
- HCI_INIT_TIMEOUT, NULL);
+ err = __hci_cmd_sync_status(hdev, HCI_OP_WRITE_AUTH_ENABLE,
+ 1, &dr.dev_opt, HCI_CMD_TIMEOUT);
break;
case HCISETENCRYPT:
@@ -766,19 +723,23 @@ int hci_dev_cmd(unsigned int cmd, void _
if (!test_bit(HCI_AUTH, &hdev->flags)) {
/* Auth must be enabled first */
- err = hci_req_sync(hdev, hci_auth_req, dr.dev_opt,
- HCI_INIT_TIMEOUT, NULL);
+ err = __hci_cmd_sync_status(hdev,
+ HCI_OP_WRITE_AUTH_ENABLE,
+ 1, &dr.dev_opt,
+ HCI_CMD_TIMEOUT);
if (err)
break;
}
- err = hci_req_sync(hdev, hci_encrypt_req, dr.dev_opt,
- HCI_INIT_TIMEOUT, NULL);
+ err = __hci_cmd_sync_status(hdev, HCI_OP_WRITE_ENCRYPT_MODE,
+ 1, &dr.dev_opt,
+ HCI_CMD_TIMEOUT);
break;
case HCISETSCAN:
- err = hci_req_sync(hdev, hci_scan_req, dr.dev_opt,
- HCI_INIT_TIMEOUT, NULL);
+ err = __hci_cmd_sync_status(hdev, HCI_OP_WRITE_SCAN_ENABLE,
+ 1, &dr.dev_opt,
+ HCI_CMD_TIMEOUT);
/* Ensure that the connectable and discoverable states
* get correctly modified as this was a non-mgmt change.
@@ -788,8 +749,11 @@ int hci_dev_cmd(unsigned int cmd, void _
break;
case HCISETLINKPOL:
- err = hci_req_sync(hdev, hci_linkpol_req, dr.dev_opt,
- HCI_INIT_TIMEOUT, NULL);
+ policy = cpu_to_le16(dr.dev_opt);
+
+ err = __hci_cmd_sync_status(hdev, HCI_OP_WRITE_DEF_LINK_POLICY,
+ 2, &policy,
+ HCI_CMD_TIMEOUT);
break;
case HCISETLINKMODE:
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -280,6 +280,19 @@ int __hci_cmd_sync_status(struct hci_dev
}
EXPORT_SYMBOL(__hci_cmd_sync_status);
+int hci_cmd_sync_status(struct hci_dev *hdev, u16 opcode, u32 plen,
+ const void *param, u32 timeout)
+{
+ int err;
+
+ hci_req_sync_lock(hdev);
+ err = __hci_cmd_sync_status(hdev, opcode, plen, param, timeout);
+ hci_req_sync_unlock(hdev);
+
+ return err;
+}
+EXPORT_SYMBOL(hci_cmd_sync_status);
+
static void hci_cmd_sync_work(struct work_struct *work)
{
struct hci_dev *hdev = container_of(work, struct hci_dev, cmd_sync_work);
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6762,6 +6762,8 @@ static void l2cap_conless_channel(struct
BT_DBG("chan %p, len %d", chan, skb->len);
+ l2cap_chan_lock(chan);
+
if (chan->state != BT_BOUND && chan->state != BT_CONNECTED)
goto drop;
@@ -6778,6 +6780,7 @@ static void l2cap_conless_channel(struct
}
drop:
+ l2cap_chan_unlock(chan);
l2cap_chan_put(chan);
free_skb:
kfree_skb(skb);
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1500,18 +1500,9 @@ static int l2cap_sock_recv_cb(struct l2c
struct l2cap_pinfo *pi;
int err;
- /* To avoid race with sock_release, a chan lock needs to be added here
- * to synchronize the sock.
- */
- l2cap_chan_hold(chan);
- l2cap_chan_lock(chan);
sk = chan->data;
-
- if (!sk) {
- l2cap_chan_unlock(chan);
- l2cap_chan_put(chan);
+ if (!sk)
return -ENXIO;
- }
pi = l2cap_pi(sk);
lock_sock(sk);
@@ -1563,8 +1554,6 @@ static int l2cap_sock_recv_cb(struct l2c
done:
release_sock(sk);
- l2cap_chan_unlock(chan);
- l2cap_chan_put(chan);
return err;
}
