5.4-stable review patch. If anyone has any objections, please let me know.
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From: Andrei Kuchynski akuchynski@chromium.org
commit 099cf1fbb8afc3771f408109f62bdec66f85160e upstream.
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 stable@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 Link: https://lore.kernel.org/r/20250624133246.3936737-1-akuchynski@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/altmodes/displayport.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -289,8 +289,7 @@ static int dp_altmode_vdm(struct typec_a 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;