From: Łukasz Bartosik ukaszb@chromium.org
[ Upstream commit 1f73b8b56cf35de29a433aee7bfff26cea98be3f ]
When DbC is disconnected then xhci_dbc_tty_unregister_device() is called. However if there is any user space process blocked on write to DbC terminal device then it will never be signalled and thus stay blocked indifinitely.
This fix adds a tty_vhangup() call in xhci_dbc_tty_unregister_device(). The tty_vhangup() wakes up any blocked writers and causes subsequent write attempts to DbC terminal device to fail.
Cc: stable stable@kernel.org Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Łukasz Bartosik ukaszb@chromium.org Link: https://patch.msgid.link/20251119212910.1245694-1-ukaszb@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [ Adjust context ] Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/host/xhci-dbgtty.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c index 980235169d811..d03eea7beeca0 100644 --- a/drivers/usb/host/xhci-dbgtty.c +++ b/drivers/usb/host/xhci-dbgtty.c @@ -468,6 +468,12 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
if (!port->registered) return; + /* + * Hang up the TTY. This wakes up any blocked + * writers and causes subsequent writes to fail. + */ + tty_vhangup(port->port.tty); + tty_unregister_device(dbc_tty_driver, 0); xhci_dbc_tty_exit_port(port); port->registered = false;