From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A62D4E73DD; Mon, 19 Oct 2026 12:34:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792413294; cv=none; b=oTQOgyvGYCs1n11eJ6f94gxOg2HrRsXND1Rz99kBWk9ebUCAcJ0ev4wWvd0SieZc3g2Lw2OlK71LerPpRTlyeJ6CZrwkHeAAOD27Ku7uAEL7NLvrKDDe/VvGZNrm3noZmiNV1e0HAVzF46FysmMjdCNHy15EFG1U2ockyHUkAbE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792413294; c=relaxed/simple; bh=FIumoOSiyMnllkdH7vaQGmgMeA2n14LStVbQbffjoB4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BcPiLXcMN5FNZmnyVyH4PgwQQTCzS81kGy9UylZIppN2H/pyPf4j9IdDgGbDuj3RaFyNZdImH25fg7q0iJNKROEx50TqXvf2n6BMhyvin029vKeaGtWsTCYNM9ZGWq0PpisXr6y1PY/7IccgDjkG4MWayHcTweXcmSW1f9gskKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JAjlQDRV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JAjlQDRV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13DC01F000C4; Mon, 19 Oct 2026 12:34:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792413278; bh=pfqRwNvIDXgUK6rGQbaCri0jI6Kk8YS9TVYwG5chEmA=; h=From:To:Cc:Subject:Date; b=JAjlQDRVWQwBdvZpZ07ULBaVloHNT/S/NQPi1JoD5macBPZM+Q8vMwqqwfYGUjR92 K97xaFoCGYtxkRombanMP3u6Sqm6IFCSKiANyS+ylk2D/918ZavMXI6Vr/v472jIBU p76q1VjWJSaPfYGQXZIRp8oiq1W5lpeiDPXLbn2WmN9rzgtbwtut/SR7DJZjnNfZ3P /3HZ/xyK8b6Di1uaIq7PGjPnCCMfaAGIRPZd3TTugFOzBmZE/DGIJTN81J8CoeziZs sQYnsVWCKUlFcQDokW6qAXMqWggwPI80wLrASB/DSKdXq9P0q1XyL4nW+Qy3OiF67e yVy+wWA3YgfhQ== Received: from johan by xi.lan with local (Exim 4.99.5) (envelope-from ) id 1xImZX-00000008QJ0-3pYq; Mon, 19 Oct 2026 14:34:35 +0200 From: Johan Hovold To: Johan Hovold Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Maksim Salau Subject: [PATCH] USB: serial: upd78f0730: fix NULL-deref on hangup Date: Mon, 19 Oct 2026 14:34:12 +0200 Message-ID: <20261019123412.2007715-1-johan@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The port tty pointer is cleared on hangup before deasserting the modem control signals and should not be used in the dtr_rts() callback. Factor out a new upd78f0730_port_tiocmset() helper that can be used in upd78f0730_dtr_rts() to avoid dereferencing a NULL-pointer on hangup (e.g. on disconnect). This issue was flagged by an LLM. Fixes: ea534e0b4047 ("USB: serial: add uPD78F0730 USB to Serial Adaptor Driver") Cc: stable@vger.kernel.org # 4.11 Cc: Maksim Salau Assisted-by: LLM Signed-off-by: Johan Hovold --- drivers/usb/serial/upd78f0730.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/usb/serial/upd78f0730.c b/drivers/usb/serial/upd78f0730.c index 78c4d3c19a8e..f2189b994ed7 100644 --- a/drivers/usb/serial/upd78f0730.c +++ b/drivers/usb/serial/upd78f0730.c @@ -201,10 +201,9 @@ static int upd78f0730_tiocmget(struct tty_struct *tty) return res; } -static int upd78f0730_tiocmset(struct tty_struct *tty, +static int upd78f0730_port_tiocmset(struct usb_serial_port *port, unsigned int set, unsigned int clear) { - struct usb_serial_port *port = tty->driver_data; struct upd78f0730_port_private *private; struct upd78f0730_set_dtr_rts request; struct device *dev = &port->dev; @@ -238,6 +237,13 @@ static int upd78f0730_tiocmset(struct tty_struct *tty, return res; } +static int upd78f0730_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear) +{ + struct usb_serial_port *port = tty->driver_data; + + return upd78f0730_port_tiocmset(port, set, clear); +} + static int upd78f0730_break_ctl(struct tty_struct *tty, int break_state) { struct upd78f0730_port_private *private; @@ -267,7 +273,6 @@ static int upd78f0730_break_ctl(struct tty_struct *tty, int break_state) static void upd78f0730_dtr_rts(struct usb_serial_port *port, int on) { - struct tty_struct *tty = port->port.tty; unsigned int set = 0; unsigned int clear = 0; @@ -276,7 +281,7 @@ static void upd78f0730_dtr_rts(struct usb_serial_port *port, int on) else clear = TIOCM_DTR | TIOCM_RTS; - upd78f0730_tiocmset(tty, set, clear); + upd78f0730_port_tiocmset(port, set, clear); } static speed_t upd78f0730_get_baud_rate(struct tty_struct *tty) -- 2.55.0