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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+e87ebe0f7913f71f2ea5@syzkaller.appspotmail.com,
        Johan Hovold <johan@kernel.org>
Subject: [PATCH 4.9 29/45] USB: yurex: fix control-URB timeout handling
Date:   Mon, 11 Jan 2021 14:01:07 +0100
Message-Id: <20210111130035.052449158@linuxfoundation.org>
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From: Johan Hovold <johan@kernel.org>

commit 372c93131998c0622304bed118322d2a04489e63 upstream.

Make sure to always cancel the control URB in write() so that it can be
reused after a timeout or spurious CMD_ACK.

Currently any further write requests after a timeout would fail after
triggering a WARN() in usb_submit_urb() when attempting to submit the
already active URB.

Reported-by: syzbot+e87ebe0f7913f71f2ea5@syzkaller.appspotmail.com
Fixes: 6bc235a2e24a ("USB: add driver for Meywa-Denki & Kayac YUREX")
Cc: stable <stable@vger.kernel.org>     # 2.6.37
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/misc/yurex.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/usb/misc/yurex.c
+++ b/drivers/usb/misc/yurex.c
@@ -507,6 +507,9 @@ static ssize_t yurex_write(struct file *
 		timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
 	finish_wait(&dev->waitq, &wait);
 
+	/* make sure URB is idle after timeout or (spurious) CMD_ACK */
+	usb_kill_urb(dev->cntl_urb);
+
 	mutex_unlock(&dev->io_mutex);
 
 	if (retval < 0) {