4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bin Liu <[email protected]>

commit 9aea9b6cc78d2b99b23d84fb2e0bc6e464c6569e upstream.

The usb_request pointer could be NULL in musb_g_tx(), where the
tracepoint call would trigger the NULL pointer dereference failure when
parsing the members of the usb_request pointer.

Move the tracepoint call to where the usb_request pointer is already
checked to solve the issue.

Fixes: fc78003e5345 ("usb: musb: gadget: add usb-request tracepoints")
Cc: [email protected] # v4.8+
Signed-off-by: Bin Liu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/usb/musb/musb_gadget.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -442,7 +442,6 @@ void musb_g_tx(struct musb *musb, u8 epn
        req = next_request(musb_ep);
        request = &req->request;
 
-       trace_musb_req_tx(req);
        csr = musb_readw(epio, MUSB_TXCSR);
        musb_dbg(musb, "<== %s, txcsr %04x", musb_ep->end_point.name, csr);
 
@@ -481,6 +480,8 @@ void musb_g_tx(struct musb *musb, u8 epn
                u8      is_dma = 0;
                bool    short_packet = false;
 
+               trace_musb_req_tx(req);
+
                if (dma && (csr & MUSB_TXCSR_DMAENAB)) {
                        is_dma = 1;
                        csr |= MUSB_TXCSR_P_WZC_BITS;


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