Greg Kroah-Hartman wrote: [..]
This is odd.
Does the latest 6.10.y release also show this problem?
I can't duplicate this here, and it's the first I've heard of it (given that USB mice are pretty popular, I would suspect others would have hit it as well...)
Sorry for missing this earlier. One thought is that userspace has a dependency on uevent_show() flushing device probing. In other words the side effect of taking the device_lock() in uevent_show() is that udev might enjoy some occasions where the reading the uevent flushes probing before the udev rule runs. With this change, uevent_show() no longer waits for any inflight probes to complete.
One idea to fix this problem is to create a special case sysfs attribute type that takes the device_lock() before kernfs_get_active() to avoid the deadlock on attribute teardown.
I'll take a look. Thanks for forwarding the report Thorsten!