[PATCH AUTOSEL 5.4 3/7] usb: typec: ucsi: Fix null pointer dereference in trace

Sasha Levin
2024-07-28T16:10:41Z

From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

[ Upstream commit 99516f76db48e1a9d54cdfed63c1babcee4e71a5 ]

ucsi_register_altmode checks IS_ERR for the alt pointer and treats
NULL as valid. When CONFIG_TYPEC_DP_ALTMODE is not enabled,
ucsi_register_displayport returns NULL which causes a NULL pointer
dereference in trace. Rather than return NULL, call
typec_port_register_altmode to register DisplayPort alternate mode
as a non-controllable mode when CONFIG_TYPEC_DP_ALTMODE is not enabled.

Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Jameson Thies <jthies@google.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240510201244.2968152-2-jthies@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/typec/ucsi/ucsi.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index de87d0b8319d0..179ad343f42f0 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -446,7 +446,7 @@ ucsi_register_displayport(struct ucsi_connector *con,
bool override, int offset,
struct typec_altmode_desc *desc)
{
- return NULL;
+ return typec_port_register_altmode(con->port, desc);
}

static inline void
--
2.43.0