[PATCH 6.18.y] serial: abort TIOCMIWAIT on hangup

[Sasha Levin <sashal@kernel.org>]

From: Johan Hovold <johan@kernel.org>

[ Upstream commit eb35b73e133686e5b999eb7130c4e3d22fe03089 ]

Add the missing hangup check to the TIOCMIWAIT wait loop to avoid going
back to sleep (indefinitely) after being woken on hangup.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: sashiko-bot@kernel.org
Link: https://lore.kernel.org/r/20260904115542.E20D11F00A3D@smtp.kernel.org
Cc: stable@kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260910130816.642699-5-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Depends on <20261005214655.3401887-1-sashal@kernel.org>

 drivers/tty/serial/serial_core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 2bbccc376dc73..be0b01d7f427a 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1251,6 +1251,11 @@ static int uart_wait_modem_status(struct tty_struct *tty, struct uart_state *sta
 			break;
 		}
 
+		if (tty_io_error(tty)) {
+			ret = -EIO;
+			break;
+		}
+
 		schedule();
 
 		/* see if a signal did it */
-- 
2.53.0