On Tue, Jun 24, 2025 at 01:32:46PM +0000, Andrei Kuchynski wrote:

The deadlock can occur due to a recursive lock acquisition of `cros_typec_altmode_data::mutex`. The call chain is as follows:

1. cros_typec_altmode_work() acquires the mutex
2. typec_altmode_vdm() -> dp_altmode_vdm() ->
3. typec_altmode_exit() -> cros_typec_altmode_exit()
4. cros_typec_altmode_exit() attempts to acquire the mutex again

To prevent this, defer the `typec_altmode_exit()` call by scheduling it rather than calling it directly from within the mutex-protected context.

Cc: stable@vger.kernel.org Fixes: b4b38ffb38c9 ("usb: typec: displayport: Receive DP Status Update NAK request exit dp altmode") Signed-off-by: Andrei Kuchynski akuchynski@chromium.org

Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com

---

drivers/usb/typec/altmodes/displayport.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index b09b58d7311d..2abbe4de3216 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -394,8 +394,7 @@ static int dp_altmode_vdm(struct typec_altmode *alt, case CMDT_RSP_NAK: switch (cmd) { case DP_CMD_STATUS_UPDATE:

• 	if (typec_altmode_exit(alt))
  

• 		dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
  

• 	dp->state = DP_STATE_EXIT;
  break;
  

  case DP_CMD_CONFIGURE: dp->data.conf = 0;