In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: run gadget disconnect from sleepable suspend context
dwc3_gadget_suspend() takes dwc->lock with IRQs disabled and then calls
dwc3_disconnect_gadget(). For async callbacks that helper only uses
plain spin_unlock()/spin_lock(), so the gadget ->disconnect() callback
still runs with IRQs disabled and any sleepable callback trips Lockdep.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the dwc3_gadget_suspend() ->
dwc3_disconnect_gadget() -> gadget_driver->disconnect() chain, and
Lockdep reported:
BUG: sleeping function called from invalid context
gadget_disconnect+0x21/0x39 [vuln_msv]
dwc3_gadget_suspend.constprop.0+0x2b/0x42 [vuln_msv]
Keep the disconnect callback selection in one common helper, but add a
sleepable suspend-side wrapper which snapshots the callback under
dwc->lock and then runs it after spin_unlock_irqrestore(). The regular
event path still uses the existing spin_unlock()/spin_lock() window.