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This lets it race against hci_dev_do_close() -> btintel_shutdown_combined(), which also runs __hci_cmd_sync() under the same lock. When both paths manipulate hdev->req_status/req_rsp concurrently, the close path may free the response skb first, and the still-running hw_error path hits a slab-use-after-free in kfree_skb(). Wrap the whole recovery sequence in hci_req_sync_lock/unlock so it is serialized with every other synchronous HCI command issuer. Below is the data race report and the kasan report: BUG: data-race in __hci_cmd_sync_sk / btintel_shutdown_combined read of hdev->req_rsp at net/bluetooth/hci_sync.c:199 by task kworker/u17:1/83: __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200 __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223 btintel_hw_error+0x114/0x670 drivers/bluetooth/btintel.c:254 hci_error_reset+0x348/0xa30 net/bluetooth/hci_core.c:1030 write/free by task ioctl/22580: btintel_shutdown_combined+0xd0/0x360 drivers/bluetooth/btintel.c:3648 hci_dev_close_sync+0x9ae/0x2c10 net/bluetooth/hci_sync.c:5246 hci_dev_do_close+0x232/0x460 net/bluetooth/hci_core.c:526 BUG: KASAN: slab-use-after-free in sk_skb_reason_drop+0x43/0x380 net/core/skbuff.c:1202 Read of size 4 at addr ffff888144a738dc by task kworker/u17:1/83: __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200 __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223 btintel_hw_error+0x186/0x670 drivers/bluetooth/btintel.c:260 Fixes: 973bb97e5aee ("Bluetooth: btintel: Add generic function for handling= hardware errors") Signed-off-by: Cen Zhang --- drivers/bluetooth/btintel.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c index 246b6205c5e0..ab146894ba4e 100644 --- a/drivers/bluetooth/btintel.c +++ b/drivers/bluetooth/btintel.c @@ -251,11 +251,13 @@ void btintel_hw_error(struct hci_dev *hdev, u8 code) =20 bt_dev_err(hdev, "Hardware error 0x%2.2x", code); =20 + hci_req_sync_lock(hdev); + skb =3D __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_INIT_TIMEOUT); if (IS_ERR(skb)) { bt_dev_err(hdev, "Reset after hardware error failed (%ld)", PTR_ERR(skb)); - return; + goto unlock; } kfree_skb(skb); =20 @@ -263,18 +265,21 @@ void btintel_hw_error(struct hci_dev *hdev, u8 code) if (IS_ERR(skb)) { bt_dev_err(hdev, "Retrieving Intel exception info failed (%ld)", PTR_ERR(skb)); - return; + goto unlock; } =20 if (skb->len !=3D 13) { bt_dev_err(hdev, "Exception info size mismatch"); kfree_skb(skb); - return; + goto unlock; } =20 bt_dev_err(hdev, "Exception info %s", (char *)(skb->data + 1)); =20 kfree_skb(skb); + +unlock: + hci_req_sync_unlock(hdev); } EXPORT_SYMBOL_GPL(btintel_hw_error); =20 --=20 2.34.1