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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Johan Hovold" <johan@kernel.org>
Date:   Sun, 11 Feb 2018 04:20:06 +0000
Message-ID: <lsq.1518322806.398736932@decadent.org.uk>
Subject: [PATCH 3.2 05/79] USB: serial: garmin_gps: fix I/O after failed
 probe and remove
In-Reply-To: <lsq.1518322802.943358572@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.2.99-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 19a565d9af6e0d828bd0d521d3bafd5017f4ce52 upstream.

Make sure to stop any submitted interrupt and bulk-out URBs before
returning after failed probe and when the port is being unbound to avoid
later NULL-pointer dereferences in the completion callbacks.

Also fix up the related and broken I/O cancellation on failed open and
on close. (Note that port->write_urb was never submitted.)

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/usb/serial/garmin_gps.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -142,6 +142,7 @@ struct garmin_data {
 	__u8   privpkt[4*6];
 	spinlock_t lock;
 	struct list_head pktlist;
+	struct usb_anchor write_urbs;
 };
 
 
@@ -923,7 +924,7 @@ static int garmin_init_session(struct us
 					sizeof(GARMIN_START_SESSION_REQ), 0);
 
 			if (status < 0)
-				break;
+				goto err_kill_urbs;
 		}
 
 		if (status > 0)
@@ -931,6 +932,12 @@ static int garmin_init_session(struct us
 	}
 
 	return status;
+
+err_kill_urbs:
+	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
+	usb_kill_urb(port->interrupt_in_urb);
+
+	return status;
 }
 
 
@@ -950,7 +957,6 @@ static int garmin_open(struct tty_struct
 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 
 	/* shutdown any bulk reads that might be going on */
-	usb_kill_urb(port->write_urb);
 	usb_kill_urb(port->read_urb);
 
 	if (garmin_data_p->state == STATE_RESET)
@@ -977,7 +983,7 @@ static void garmin_close(struct usb_seri
 
 	/* shutdown our urbs */
 	usb_kill_urb(port->read_urb);
-	usb_kill_urb(port->write_urb);
+	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
 
 	/* keep reset state so we know that we must start a new session */
 	if (garmin_data_p->state != STATE_RESET)
@@ -1069,12 +1075,14 @@ static int garmin_write_bulk(struct usb_
 	}
 
 	/* send it down the pipe */
+	usb_anchor_urb(urb, &garmin_data_p->write_urbs);
 	status = usb_submit_urb(urb, GFP_ATOMIC);
 	if (status) {
 		dev_err(&port->dev,
 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
 				__func__, status);
 		count = status;
+		usb_unanchor_urb(urb);
 		kfree(buffer);
 	}
 
@@ -1464,6 +1472,7 @@ static int garmin_attach(struct usb_seri
 	garmin_data_p->state = 0;
 	garmin_data_p->flags = 0;
 	garmin_data_p->count = 0;
+	init_usb_anchor(&garmin_data_p->write_urbs);
 	usb_set_serial_port_data(port, garmin_data_p);
 
 	status = garmin_init_session(port);
@@ -1479,6 +1488,7 @@ static void garmin_disconnect(struct usb
 
 	dbg("%s", __func__);
 
+	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
 	usb_kill_urb(port->interrupt_in_urb);
 	del_timer_sync(&garmin_data_p->timer);
 }