From a12cf3214235681a347a53c93378479caab3f404 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Thu, 30 Jun 2016 17:10:23 +0800 Subject: [PATCH] usb: gadget: Add the gserial port checking in gs_start_tx() commit 511a36d2f357724312bb3776d2f6eed3890928b2 upstream. When usb gadget is set gadget serial function, it will be crash in below situation. 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 Signed-off-by: Felipe Balbi Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/u_serial.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index 4ea44f7122ee..d73618475664 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -361,10 +361,15 @@ __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;