FAILED: patch "[PATCH] xhci: dbgtty: fix device unregister: fixup" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] xhci: dbgtty: fix device unregister: fixup" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 74098cc06e753d3ffd8398b040a3a1dfb65260c0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025122917-keenly-greyhound-4fa6@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 74098cc06e753d3ffd8398b040a3a1dfb65260c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Bartosik?= <ukaszb@chromium.org>
Date: Thu, 27 Nov 2025 11:16:44 +0000
Subject: [PATCH] xhci: dbgtty: fix device unregister: fixup
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This fixup replaces tty_vhangup() call with call to
tty_port_tty_vhangup(). Both calls hangup tty device
synchronously however tty_port_tty_vhangup() increases
reference count during the hangup operation using
scoped_guard(tty_port_tty).

Cc: stable <stable@kernel.org>
Fixes: 1f73b8b56cf3 ("xhci: dbgtty: fix device unregister")
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Link: https://patch.msgid.link/20251127111644.3161386-1-ukaszb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index 57cdda4e09c8..90282e51e23e 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -554,7 +554,7 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
 	 * Hang up the TTY. This wakes up any blocked
 	 * writers and causes subsequent writes to fail.
 	 */
-	tty_vhangup(port->port.tty);
+	tty_port_tty_vhangup(&port->port);
 
 	tty_unregister_device(dbc_tty_driver, port->minor);
 	xhci_dbc_tty_exit_port(port);

[PATCH 6.6.y 1/2] tty: introduce and use tty_port_tty_vhangup() helper

[Sasha Levin]

From: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>

[ Upstream commit 2b5eac0f8c6e79bc152c8804f9f88d16717013ab ]

This code (tty_get -> vhangup -> tty_put) is repeated on few places.
Introduce a helper similar to tty_port_tty_hangup() (asynchronous) to
handle even vhangup (synchronous).

And use it on those places.

In fact, reuse the tty_port_tty_hangup()'s code and call tty_vhangup()
depending on a new bool parameter.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: David Lin <dtwlin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Alex Elder <elder@kernel.org>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/isdn/capi/capi.c         |  8 +-------
 drivers/staging/greybus/uart.c   |  7 +------
 drivers/tty/serial/serial_core.c |  7 +------
 drivers/tty/tty_port.c           | 12 ++++++++----
 drivers/usb/class/cdc-acm.c      |  7 +------
 drivers/usb/serial/usb-serial.c  |  7 +------
 include/linux/tty_port.h         | 12 +++++++++++-
 net/bluetooth/rfcomm/tty.c       |  7 +------
 8 files changed, 25 insertions(+), 42 deletions(-)

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 2f3789515445..11a1a26f7510 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -304,15 +304,9 @@ static void capincci_alloc_minor(struct capidev *cdev, struct capincci *np)
 static void capincci_free_minor(struct capincci *np)
 {
 	struct capiminor *mp = np->minorp;
-	struct tty_struct *tty;
 
 	if (mp) {
-		tty = tty_port_tty_get(&mp->port);
-		if (tty) {
-			tty_vhangup(tty);
-			tty_kref_put(tty);
-		}
-
+		tty_port_tty_vhangup(&mp->port);
 		capiminor_free(mp);
 	}
 }
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index 999ce613dca8..526573556cda 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -914,7 +914,6 @@ static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 {
 	struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
 	struct gb_connection *connection = gb_tty->connection;
-	struct tty_struct *tty;
 	int ret;
 
 	ret = gbphy_runtime_get_sync(gbphy_dev);
@@ -927,11 +926,7 @@ static void gb_uart_remove(struct gbphy_device *gbphy_dev)
 	wake_up_all(&gb_tty->wioctl);
 	mutex_unlock(&gb_tty->mutex);
 
-	tty = tty_port_tty_get(&gb_tty->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&gb_tty->port);
 
 	gb_connection_disable_rx(connection);
 	tty_unregister_device(gb_tty_driver, gb_tty->minor);
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 8ff0efac6aa0..c3a51bd59ff7 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3250,7 +3250,6 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 	struct uart_state *state = drv->state + uport->line;
 	struct tty_port *port = &state->port;
 	struct uart_port *uart_port;
-	struct tty_struct *tty;
 
 	mutex_lock(&port->mutex);
 	uart_port = uart_port_check(state);
@@ -3269,11 +3268,7 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
 	 */
 	tty_port_unregister_device(port, drv->tty_driver, uport->line);
 
-	tty = tty_port_tty_get(port);
-	if (tty) {
-		tty_vhangup(port->tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(port);
 
 	/*
 	 * If the port is used as a console, unregister it
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 624d104bd145..eb51d1f10d56 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -414,15 +414,19 @@ EXPORT_SYMBOL(tty_port_hangup);
  * @port: tty port
  * @check_clocal: hang only ttys with %CLOCAL unset?
  */
-void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async)
 {
 	struct tty_struct *tty = tty_port_tty_get(port);
 
-	if (tty && (!check_clocal || !C_CLOCAL(tty)))
-		tty_hangup(tty);
+	if (tty && (!check_clocal || !C_CLOCAL(tty))) {
+		if (async)
+			tty_hangup(tty);
+		else
+			tty_vhangup(tty);
+	}
 	tty_kref_put(tty);
 }
-EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
+EXPORT_SYMBOL_GPL(__tty_port_tty_hangup);
 
 /**
  * tty_port_tty_wakeup - helper to wake up a tty
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index f0c87c914149..c0c4a9415a76 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1572,7 +1572,6 @@ static int acm_probe(struct usb_interface *intf,
 static void acm_disconnect(struct usb_interface *intf)
 {
 	struct acm *acm = usb_get_intfdata(intf);
-	struct tty_struct *tty;
 	int i;
 
 	/* sibling interface is already cleaning up */
@@ -1599,11 +1598,7 @@ static void acm_disconnect(struct usb_interface *intf)
 	usb_set_intfdata(acm->data, NULL);
 	mutex_unlock(&acm->mutex);
 
-	tty = tty_port_tty_get(&acm->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&acm->port);
 
 	cancel_delayed_work_sync(&acm->dwork);
 
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 17b09f03ef84..be81d4a2f79f 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1178,7 +1178,6 @@ static void usb_serial_disconnect(struct usb_interface *interface)
 	struct usb_serial *serial = usb_get_intfdata(interface);
 	struct device *dev = &interface->dev;
 	struct usb_serial_port *port;
-	struct tty_struct *tty;
 
 	/* sibling interface is cleaning up */
 	if (!serial)
@@ -1193,11 +1192,7 @@ static void usb_serial_disconnect(struct usb_interface *interface)
 
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
-		tty = tty_port_tty_get(&port->port);
-		if (tty) {
-			tty_vhangup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_vhangup(&port->port);
 		usb_serial_port_poison_urbs(port);
 		wake_up_interruptible(&port->port.delta_msr_wait);
 		cancel_work_sync(&port->work);
diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index 6b367eb17979..bd025c6f3a20 100644
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -235,7 +235,7 @@ bool tty_port_carrier_raised(struct tty_port *port);
 void tty_port_raise_dtr_rts(struct tty_port *port);
 void tty_port_lower_dtr_rts(struct tty_port *port);
 void tty_port_hangup(struct tty_port *port);
-void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
+void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async);
 void tty_port_tty_wakeup(struct tty_port *port);
 int tty_port_block_til_ready(struct tty_port *port, struct tty_struct *tty,
 		struct file *filp);
@@ -254,4 +254,14 @@ static inline int tty_port_users(struct tty_port *port)
 	return port->count + port->blocked_open;
 }
 
+static inline void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+{
+	__tty_port_tty_hangup(port, check_clocal, true);
+}
+
+static inline void tty_port_tty_vhangup(struct tty_port *port)
+{
+	__tty_port_tty_hangup(port, false, false);
+}
+
 #endif
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index e258ca191470..912e37cb8310 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -438,7 +438,6 @@ static int __rfcomm_release_dev(void __user *arg)
 {
 	struct rfcomm_dev_req req;
 	struct rfcomm_dev *dev;
-	struct tty_struct *tty;
 
 	if (copy_from_user(&req, arg, sizeof(req)))
 		return -EFAULT;
@@ -464,11 +463,7 @@ static int __rfcomm_release_dev(void __user *arg)
 		rfcomm_dlc_close(dev->dlc, 0);
 
 	/* Shut down TTY synchronously before freeing rfcomm_dev */
-	tty = tty_port_tty_get(&dev->port);
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_vhangup(&dev->port);
 
 	if (!test_bit(RFCOMM_TTY_OWNED, &dev->status))
 		tty_port_put(&dev->port);
-- 
2.51.0

[PATCH 6.6.y 2/2] xhci: dbgtty: fix device unregister: fixup

[Sasha Levin]

From: Łukasz Bartosik <ukaszb@chromium.org>

[ Upstream commit 74098cc06e753d3ffd8398b040a3a1dfb65260c0 ]

This fixup replaces tty_vhangup() call with call to
tty_port_tty_vhangup(). Both calls hangup tty device
synchronously however tty_port_tty_vhangup() increases
reference count during the hangup operation using
scoped_guard(tty_port_tty).

Cc: stable <stable@kernel.org>
Fixes: 1f73b8b56cf3 ("xhci: dbgtty: fix device unregister")
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Link: https://patch.msgid.link/20251127111644.3161386-1-ukaszb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/host/xhci-dbgtty.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index f2c74e20b572..3bc7bb958524 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -522,7 +522,7 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
 	 * Hang up the TTY. This wakes up any blocked
 	 * writers and causes subsequent writes to fail.
 	 */
-	tty_vhangup(port->port.tty);
+	tty_port_tty_vhangup(&port->port);
 
 	tty_unregister_device(dbc_tty_driver, port->minor);
 	xhci_dbc_tty_exit_port(port);
-- 
2.51.0

[PATCH 6.6.y] xhci: dbgtty: fix device unregister: fixup

[Łukasz Bartosik]

This fixup replaces tty_vhangup() call with call to
tty_port_tty_vhangup(). Both calls hangup tty device
synchronously however tty_port_tty_vhangup() increases
reference count during the hangup operation using
scoped_guard(tty_port_tty).

Cc: stable <stable@kernel.org>
Fixes: 1f73b8b56cf3 ("xhci: dbgtty: fix device unregister")
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Link: https://patch.msgid.link/20251127111644.3161386-1-ukaszb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci-dbgtty.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index f2c74e20b572..fc057391abd3 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -515,6 +515,7 @@ static int xhci_dbc_tty_register_device(struct xhci_dbc *dbc)
 static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
 {
 	struct dbc_port		*port = dbc_to_port(dbc);
+	struct tty_struct	*tty;
 
 	if (!port->registered)
 		return;
@@ -522,7 +523,11 @@ static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc)
 	 * Hang up the TTY. This wakes up any blocked
 	 * writers and causes subsequent writes to fail.
 	 */
-	tty_vhangup(port->port.tty);
+	tty = tty_port_tty_get(&port->port);
+	if (tty) {
+		tty_vhangup(tty);
+		tty_kref_put(tty);
+	}
 
 	tty_unregister_device(dbc_tty_driver, port->minor);
 	xhci_dbc_tty_exit_port(port);
-- 
2.52.0.351.gbe84eed79e-goog

Re: [PATCH 6.6.y] xhci: dbgtty: fix device unregister: fixup

[Greg Kroah-Hartman]

On Wed, Jan 07, 2026 at 12:25:20AM +0000, Łukasz Bartosik wrote:
> This fixup replaces tty_vhangup() call with call to
> tty_port_tty_vhangup(). Both calls hangup tty device
> synchronously however tty_port_tty_vhangup() increases
> reference count during the hangup operation using
> scoped_guard(tty_port_tty).
> 
> Cc: stable <stable@kernel.org>
> Fixes: 1f73b8b56cf3 ("xhci: dbgtty: fix device unregister")
> Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
> Link: https://patch.msgid.link/20251127111644.3161386-1-ukaszb@google.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/usb/host/xhci-dbgtty.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

Git id?