[PATCH 4.19 092/361] Bluetooth: hci_qca: Remove hdev dereference in qca_close().

Greg Kroah-Hartman
2018-11-12T00:12:16Z

From: Balakrishna Godavarthi <bgodavar@codeaurora.org>

[ Upstream commit c2d7827338618a9e73a3f892ca63d9082bb7a94d ]

When flag KASAN is set, we are seeing an following crash while removing
hci_uart module.

[ 50.589909] Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b73
[ 50.597902] Mem abort info:
[ 50.600846] Exception class = DABT (current EL), IL = 32 bits
[ 50.606959] SET = 0, FnV = 0
[ 50.610142] EA = 0, S1PTW = 0
[ 50.613396] Data abort info:
[ 50.616401] ISV = 0, ISS = 0x00000004
[ 50.620373] CM = 0, WnR = 0
[ 50.623466] [006b6b6b6b6b6b73] address between user and kernel address ranges
[ 50.630818] Internal error: Oops: 96000004 [#1] PREEMPT SMP

[ 50.671670] PC is at qca_power_shutdown+0x28/0x100 [hci_uart]
[ 50.677593] LR is at qca_close+0x74/0xb0 [hci_uart]
[ 50.775689] Process rmmod (pid: 2144, stack limit = 0xffffff801ba90000)
[ 50.782493] Call trace:

[ 50.872150] [<ffffff8000c3c81c>] qca_power_shutdown+0x28/0x100 [hci_uart]
[ 50.879138] [<ffffff8000c3c968>] qca_close+0x74/0xb0 [hci_uart]
[ 50.885238] [<ffffff8000c3a71c>] hci_uart_unregister_device+0x44/0x50 [hci_uart]
[ 50.892846] [<ffffff8000c3c9f4>] qca_serdev_remove+0x50/0x5c [hci_uart]
[ 50.899654] [<ffffff800844f630>] serdev_drv_remove+0x28/0x38
[ 50.905489] [<ffffff800850fc44>] device_release_driver_internal+0x140/0x1e4
[ 50.912653] [<ffffff800850fd94>] driver_detach+0x78/0x84
[ 50.918121] [<ffffff800850edac>] bus_remove_driver+0x80/0xa8
[ 50.923942] [<ffffff80085107dc>] driver_unregister+0x4c/0x58
[ 50.929768] [<ffffff8000c3ca8c>] qca_deinit+0x24/0x598 [hci_uart]
[ 50.936045] [<ffffff8000c3ca10>] hci_uart_exit+0x10/0x48 [hci_uart]
[ 50.942495] [<ffffff8008136630>] SyS_delete_module+0x17c/0x224

This crash is due to dereference of hdev, after freeing it.

Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/bluetooth/hci_qca.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -167,7 +167,7 @@ struct qca_serdev {
};

static int qca_power_setup(struct hci_uart *hu, bool on);
-static void qca_power_shutdown(struct hci_dev *hdev);
+static void qca_power_shutdown(struct hci_uart *hu);

static void __serial_clock_on(struct tty_struct *tty)
{
@@ -609,7 +609,7 @@ static int qca_close(struct hci_uart *hu
if (hu->serdev) {
qcadev = serdev_device_get_drvdata(hu->serdev);
if (qcadev->btsoc_type == QCA_WCN3990)
- qca_power_shutdown(hu->hdev);
+ qca_power_shutdown(hu);
else
gpiod_set_value_cansleep(qcadev->bt_en, 0);

@@ -1232,12 +1232,15 @@ static const struct qca_vreg_data qca_so
.num_vregs = 4,
};

-static void qca_power_shutdown(struct hci_dev *hdev)
+static void qca_power_shutdown(struct hci_uart *hu)
{
- struct hci_uart *hu = hci_get_drvdata(hdev);
+ struct serdev_device *serdev = hu->serdev;
+ unsigned char cmd = QCA_WCN3990_POWEROFF_PULSE;

host_set_baudrate(hu, 2400);
- qca_send_power_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
+ hci_uart_set_flow_control(hu, true);
+ serdev_device_write_buf(serdev, &cmd, sizeof(cmd));
+ hci_uart_set_flow_control(hu, false);
qca_power_setup(hu, false);
}

@@ -1413,7 +1416,7 @@ static void qca_serdev_remove(struct ser
struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev);

if (qcadev->btsoc_type == QCA_WCN3990)
- qca_power_shutdown(qcadev->serdev_hu.hdev);
+ qca_power_shutdown(&qcadev->serdev_hu);
else
clk_disable_unprepare(qcadev->susclk);