usb: cdc-acm: make sure a refcount is taken early enough

destroy() will decrement the refcount on the interface, so that
it needs to be taken so early that it never undercounts.

Fixes: 7fb57a019f94e ("USB: cdc-acm: Fix potential deadlock (lockdep warning)")
Cc: stable <>
Signed-off-by: Oliver Neukum <>
Signed-off-by: Greg Kroah-Hartman <>
1 file changed