From 2f2c0354534c09222f7eb9b7c063dc6fdb01a006 Mon Sep 17 00:00:00 2001 From: Kuen-Han Tsai Date: Fri, 2 Jun 2023 15:00:06 +0800 Subject: [PATCH] UPSTREAM: usb: gadget: u_serial: Add null pointer check in gs_start_io If gs_close has cleared port->port.tty and gs_start_io is called afterwards, then the function tty_wakeup will attempt to access the value of the pointer port->port.tty which will cause a null pointer dereference error. To avoid this, add a null pointer check to gs_start_io before attempting to access the value of the pointer port->port.tty. Signed-off-by: Kuen-Han Tsai Message-ID: <20230602070009.1353946-1-khtsai@google.com> Signed-off-by: Greg Kroah-Hartman Bug: 283247551 (cherry picked from commit ffd603f214237e250271162a5b325c6199a65382) Change-Id: I782ef328b0d49810d3fb23c002a86439e6728542 Signed-off-by: Kuen-Han Tsai (cherry picked from commit ca0cd377615866a0253c6e495f99fad57bbaab86) --- drivers/usb/gadget/function/u_serial.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index db6fd0238d4b..0c429f25d0ac 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -538,16 +538,20 @@ static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, static int gs_start_io(struct gs_port *port) { struct list_head *head = &port->read_pool; - struct usb_ep *ep = port->port_usb->out; + struct usb_ep *ep; int status; unsigned started; + if (!port->port_usb || !port->port.tty) + return -EIO; + /* Allocate RX and TX I/O buffers. We can't easily do this much * earlier (with GFP_KERNEL) because the requests are coupled to * endpoints, as are the packet sizes we'll be using. Different * configurations may use different endpoints with a given port; * and high speed vs full speed changes packet sizes too. */ + ep = port->port_usb->out; status = gs_alloc_requests(ep, head, gs_read_complete, &port->read_allocated); if (status)