From 615f35fd5aee169cc4881a8594f2fa234a4d0bb8 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 11 Sep 2026 11:01:32 +0200 Subject: [PATCH] tty: amiserial: fix broken TIOCMIWAIT A change replacing interruptible_sleep_on() inadvertently broke the TIOCMIWAIT implementation which now immediately returns -EIO (unless there is a racing modem status update). Replace the old hangup (and signal) detection with a check for the TTY_IO_ERROR flag which is set on hangup. Fixes: 591cee0a3563 ("tty/amiserial: avoid interruptible_sleep_on") Reported-by: sashiko-bot@kernel.org Link: https://lore.kernel.org/20260910132029.D80801F00898@smtp.kernel.org Cc: stable@kernel.org # 3.14 Cc: Arnd Bergmann Signed-off-by: Johan Hovold Reviewed-by: Jiri Slaby Link: https://patch.msgid.link/20260911090132.723531-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/amiserial.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c index 28af0fd98181..60f6060b893d 100644 --- a/drivers/tty/amiserial.c +++ b/drivers/tty/amiserial.c @@ -1138,11 +1138,6 @@ static int rs_ioctl(struct tty_struct *tty, local_irq_save(flags); cnow = info->icount; /* atomic copy */ local_irq_restore(flags); - if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr && - cnow.dcd == cprev.dcd && cnow.cts == cprev.cts) { - ret = -EIO; /* no change => error */ - break; - } if ( ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) || ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) || ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) || @@ -1150,6 +1145,10 @@ static int rs_ioctl(struct tty_struct *tty, ret = 0; break; } + if (tty_io_error(tty)) { + ret = -EIO; + break; + } schedule(); /* see if a signal did it */ if (signal_pending(current)) {