From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> commit c3bf9930921b33edb31909006607e478751a6f5e upstream. The function misses checking return value of tb_sw_read() before it accesses the value that was read. Fix this by checking the return value first. Fixes: b04079837b20 ("thunderbolt: Add initial support for USB4") Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Reviewed-by: Yehezkel Bernat <yehezkelshb@xxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/thunderbolt/usb4.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/thunderbolt/usb4.c +++ b/drivers/thunderbolt/usb4.c @@ -182,6 +182,9 @@ static int usb4_switch_op(struct tb_swit return ret; ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_26, 1); + if (ret) + return ret; + if (val & ROUTER_CS_26_ONS) return -EOPNOTSUPP;