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From: Johan Hovold <johan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH v4 1/4] serial: revert guards in uart_wait_modem_status()
Date: Thu, 10 Sep 2026 15:08:13 +0200	[thread overview]
Message-ID: <20260910130816.642699-2-johan@kernel.org> (raw)
In-Reply-To: <20260910130816.642699-1-johan@kernel.org>

Mixing scope-based and regular cleanup is discouraged and
uart_port_deref() used by uart_wait_modem_status() falls in the latter
category.

Revert the guard conversion in preparation for fixing a hangup race.

Fixes: 56609c050051 ("serial: serial_core: use guard()s")
Cc: stable@vger.kernel.org	# 6.18
Cc: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/tty/serial/serial_core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 95774b0f1484..1553bc6cbe7b 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1213,15 +1213,16 @@ static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
 	uport = uart_port_ref(state);
 	if (!uport)
 		return -EIO;
-	scoped_guard(uart_port_lock_irq, uport) {
-		memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
-		uart_enable_ms(uport);
-	}
+	uart_port_lock_irq(uport);
+	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
+	uart_enable_ms(uport);
+	uart_port_unlock_irq(uport);
 
 	add_wait_queue(&port->delta_msr_wait, &wait);
 	for (;;) {
-		scoped_guard(uart_port_lock_irq, uport)
-			memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
+		uart_port_lock_irq(uport);
+		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
+		uart_port_unlock_irq(uport);
 
 		set_current_state(TASK_INTERRUPTIBLE);
 
-- 
2.55.0


  reply	other threads:[~2026-09-10 13:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-10 13:08 [PATCH v4 0/4] serial: fix ioctl hangup race Johan Hovold
2026-09-10 13:08 ` Johan Hovold [this message]
2026-09-10 13:08 ` [PATCH v4 2/4] " Johan Hovold
2026-09-10 13:08 ` [PATCH v4 3/4] serial: fix TIOCMIWAIT race Johan Hovold
2026-09-10 13:08 ` [PATCH v4 4/4] serial: abort TIOCMIWAIT on hangup Johan Hovold

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