[RESEND] usb: gadget: Add the gserial port checking in gs_start_tx()

Message ID 11cb15ff2587d4f38f72bfdb3d5650144ba150ef.1467277321.git.baolin.wang@linaro.org
State Accepted
Commit 511a36d2f357724312bb3776d2f6eed3890928b2
Headers show

Commit Message

(Exiting) Baolin Wang Aug. 15, 2016, 7 a.m.
When usb gadget is set gadget serial function, it will be crash in below

It will clean the 'port->port_usb' pointer in gserial_disconnect() function
when usb link is inactive, but it will release lock for disabling the endpoints
in this function. Druing the lock release period, it maybe complete one request
to issue gs_write_complete()--->gs_start_tx() function, but the 'port->port_usb'
pointer had been set NULL, thus it will be crash in gs_start_tx() function.

This patch adds the 'port->port_usb' pointer checking in gs_start_tx() function
to avoid this situation.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

 drivers/usb/gadget/function/u_serial.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)


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diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 3580f19..66a0910 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -375,10 +375,15 @@  __acquires(&port->port_lock)
 	struct list_head	*pool = &port->write_pool;
-	struct usb_ep		*in = port->port_usb->in;
+	struct usb_ep		*in;
 	int			status = 0;
 	bool			do_tty_wake = false;
+	if (!port->port_usb)
+		return status;
+	in = port->port_usb->in;
 	while (!port->write_busy && !list_empty(pool)) {
 		struct usb_request	*req;
 		int			len;