From 7ed7748c94cb3d2e032cdefe7ba8e5e39dc02dcc Mon Sep 17 00:00:00 2001
From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Date: Tue, 7 May 2024 16:43:16 +0300
Subject: [PATCH] usb: typec: ucsi: displayport: Fix potential deadlock
commit b791a67f68121d69108640d4a3e591d210ffe850 upstream.
The function ucsi_displayport_work() does not access the
connector, so it also must not acquire the connector lock.
This fixes a potential deadlock scenario:
ucsi_displayport_work() -> lock(&con->lock)
typec_altmode_vdm()
dp_altmode_vdm()
dp_altmode_work()
typec_altmode_enter()
ucsi_displayport_enter() -> lock(&con->lock)
Reported-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
Cc: stable@vger.kernel.org
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240507134316.161999-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/typec/ucsi/displayport.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 261131c9e37c..4446c4066679 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -249,8 +249,6 @@ static void ucsi_displayport_work(struct work_struct *work)
struct ucsi_dp *dp = container_of(work, struct ucsi_dp, work);
int ret;
- mutex_lock(&dp->con->lock);
-
ret = typec_altmode_vdm(dp->alt, dp->header,
dp->vdo_data, dp->vdo_size);
if (ret)
@@ -259,8 +257,6 @@ static void ucsi_displayport_work(struct work_struct *work)
dp->vdo_data = NULL;
dp->vdo_size = 0;
dp->header = 0;
-
- mutex_unlock(&dp->con->lock);
}
void ucsi_displayport_remove_partner(struct typec_altmode *alt)