USB: gadget: f_midi: f_midi_complete to call queue_work

When using USB MIDI, a lock is attempted to be acquired twice through a
re-entrant call to f_midi_transmit, causing a deadlock.

Fix it by using queue_work() to schedule the inner f_midi_transmit() via
a high priority work queue from the completion handler.

Link: https://lore.kernel.org/all/CAArt=LjxU0fUZOj06X+5tkeGT+6RbXzpWg1h4t4Fwa_KGVAX6g@mail.gmail.com/
Fixes: d5daf49b58661 ("USB: gadget: midi: add midi function driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Jill Donahue <jilliandonahue58@gmail.com>
Link: https://lore.kernel.org/r/20250211174805.1369265-1-jdonahue@fender.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 47260d65066a89384ec0b9c353def8a094195bf9..da82598fcef8a814bee0052d8dc14375bc9e515b 100644 (file)
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -283,7 +283,7 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req)
                        /* Our transmit completed. See if there's more to go.
                         * f_midi_transmit eats req, don't queue it again. */
                        req->length = 0;
-                       f_midi_transmit(midi);
+                       queue_work(system_highpri_wq, &midi->work);
                        return;
                }
                break;