From daf82bd24e308c5a83758047aff1bd81edda4f11 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= <mirq-linux@rere.qmqm.pl>

Date: Sat, 10 Aug 2019 10:42:48 +0200

Subject: [PATCH] usb: gadget: u_serial: add missing port entry locking

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Git-commit: daf82bd24e308c5a83758047aff1bd81edda4f11

Patch-mainline: v5.5-rc1

References: bsc#1051510

gserial_alloc_line() misses locking (for a release barrier) while

resetting port entry on TTY allocation failure. Fix this.

Cc: stable@vger.kernel.org

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tested-by: Ladislav Michl <ladis@linux-mips.org>

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/usb/gadget/function/u_serial.c | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c

index 65f634ec7fc2..bb1e2e1d0076 100644

--- a/drivers/usb/gadget/function/u_serial.c

+++ b/drivers/usb/gadget/function/u_serial.c

@@ -1239,8 +1239,10 @@ int gserial_alloc_line(unsigned char *line_num)

 				__func__, port_num, PTR_ERR(tty_dev));

 		ret = PTR_ERR(tty_dev);

+		mutex_lock(&ports[port_num].lock);

 		port = ports[port_num].port;

 		ports[port_num].port = NULL;

+		mutex_unlock(&ports[port_num].lock);

 		gserial_free_port(port);

 		goto err;

 	}

-- 

2.16.4