6.6-stable review patch. If anyone has any objections, please let me know.
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From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
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@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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; }