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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, Bin Liu <b-liu@ti.com>,
        Johan Hovold <johan@kernel.org>
Subject: [PATCH 5.7 02/24] USB: serial: usb_wwan: do not resubmit rx urb on fatal errors
Date:   Tue,  9 Jun 2020 19:45:33 +0200
Message-Id: <20200609174149.488304314@linuxfoundation.org>
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From: Bin Liu <b-liu@ti.com>

commit 986c1748c84d7727defeaeca74a73b37f7d5cce1 upstream.

usb_wwan_indat_callback() shouldn't resubmit rx urb if the previous urb
status is a fatal error. Or the usb controller would keep processing the
new urbs then run into interrupt storm, and has no chance to recover.

Fixes: 6c1ee66a0b2b ("USB-Serial: Fix error handling of usb_wwan")
Cc: stable@vger.kernel.org
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/serial/usb_wwan.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -270,6 +270,10 @@ static void usb_wwan_indat_callback(stru
 	if (status) {
 		dev_dbg(dev, "%s: nonzero status: %d on endpoint %02x.\n",
 			__func__, status, endpoint);
+
+		/* don't resubmit on fatal errors */
+		if (status == -ESHUTDOWN || status == -ENOENT)
+			return;
 	} else {
 		if (urb->actual_length) {
 			tty_insert_flip_string(&port->port, data,