[PATCH 5.10.y 2/2] cdc-acm: fix race between initial clearing halt and open

[Sasha Levin <sashal@kernel.org>]

From: Oliver Neukum <oneukum@suse.com>

[ Upstream commit 64690a90cd7c6db16d3af8616be1f4bf8d492850 ]

On the devices that need their endpoints to get an
initial clear_halt, this needs to be done before
the devices can be opened. That means it needs to be
before the devices are registered.

Fixes: 15bf722e6f6c0 ("cdc-acm: Add support of ATOL FPrint fiscal printers")
Cc: stable <stable@kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20250717141259.2345605-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/class/cdc-acm.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 50d439201302..07543731bfa5 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1517,6 +1517,12 @@ static int acm_probe(struct usb_interface *intf,
 	usb_driver_claim_interface(&acm_driver, data_interface, acm);
 	usb_set_intfdata(data_interface, acm);
 
+	if (quirks & CLEAR_HALT_CONDITIONS) {
+		/* errors intentionally ignored */
+		usb_clear_halt(usb_dev, acm->in);
+		usb_clear_halt(usb_dev, acm->out);
+	}
+
 	tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor,
 			&control_interface->dev);
 	if (IS_ERR(tty_dev)) {
@@ -1524,11 +1530,6 @@ static int acm_probe(struct usb_interface *intf,
 		goto alloc_fail6;
 	}
 
-	if (quirks & CLEAR_HALT_CONDITIONS) {
-		usb_clear_halt(usb_dev, acm->in);
-		usb_clear_halt(usb_dev, acm->out);
-	}
-
 	dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
 
 	return 0;
-- 
2.50.1