The driver shutdown callback (which sends EDL_SOC_RESET to the device over serdev) should not be invoked when HCI device is not open (e.g. if hci_dev_open_sync() failed), because the serdev and its TTY are not open either. Also skip this step if device is powered off (qca_power_shutdown()).

The shutdown callback causes use-after-free during system reboot with Qualcomm Atheros Bluetooth:

Unable to handle kernel paging request at virtual address 0072662f67726fd7 ... CPU: 6 PID: 1 Comm: systemd-shutdow Tainted: G W 6.1.0-rt5-00325-g8a5f56bcfcca #8 Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) Call trace: tty_driver_flush_buffer+0x4/0x30 serdev_device_write_flush+0x24/0x34 qca_serdev_shutdown+0x80/0x130 [hci_uart] device_shutdown+0x15c/0x260 kernel_restart+0x48/0xac

KASAN report:

BUG: KASAN: use-after-free in tty_driver_flush_buffer+0x1c/0x50 Read of size 8 at addr ffff16270c2e0018 by task systemd-shutdow/1

CPU: 7 PID: 1 Comm: systemd-shutdow Not tainted 6.1.0-next-20221220-00014-gb85aaf97fb01-dirty #28 Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) Call trace: dump_backtrace.part.0+0xdc/0xf0 show_stack+0x18/0x30 dump_stack_lvl+0x68/0x84 print_report+0x188/0x488 kasan_report+0xa4/0xf0 __asan_load8+0x80/0xac tty_driver_flush_buffer+0x1c/0x50 ttyport_write_flush+0x34/0x44 serdev_device_write_flush+0x48/0x60 qca_serdev_shutdown+0x124/0x274 device_shutdown+0x1e8/0x350 kernel_restart+0x48/0xb0 __do_sys_reboot+0x244/0x2d0 __arm64_sys_reboot+0x54/0x70 invoke_syscall+0x60/0x190 el0_svc_common.constprop.0+0x7c/0x160 do_el0_svc+0x44/0xf0 el0_svc+0x2c/0x6c el0t_64_sync_handler+0xbc/0x140 el0t_64_sync+0x190/0x194

Fixes: 7e7bbddd029b ("Bluetooth: hci_qca: Fix qca6390 enable failure after warm reboot") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org

---

Changes since v1: 1. Drop serdev patch and fix it only on BT side. 2. Update commit msg. --- drivers/bluetooth/hci_qca.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c index bb7623fe53a8..157fc4d024c1 100644 --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c @@ -2166,10 +2166,16 @@ static void qca_serdev_shutdown(struct device *dev) int timeout = msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS); struct serdev_device *serdev = to_serdev_device(dev); struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev); + struct hci_uart *hu = &qcadev->serdev_hu; + struct hci_dev *hdev = hu->hdev; + struct qca_data *qca = hu->priv; const u8 ibs_wake_cmd[] = { 0xFD }; const u8 edl_reset_soc_cmd[] = { 0x01, 0x00, 0xFC, 0x01, 0x05 };

if (qcadev->btsoc_type == QCA_QCA6390) { + if (test_bit(QCA_BT_OFF, &qca->flags) || !test_bit(HCI_RUNNING, &hdev->flags)) + return; + serdev_device_write_flush(serdev); ret = serdev_device_write_buf(serdev, ibs_wake_cmd, sizeof(ibs_wake_cmd));