5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jill Donahue jilliandonahue58@gmail.com
[ Upstream commit 4ab37fcb42832cdd3e9d5e50653285ca84d6686f ]
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_KGVA... 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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_midi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 01c5736d381ef..3e8ea1bbe429a 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -282,7 +282,7 @@ 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;