fuse: wait for FR_FINISHED on abort_on_kill to prevent use-after-free

In the Linux kernel, the following vulnerability has been resolved: fuse: wait for FR_FINISHED on abort_on_kill to prevent use-after-free The abort_on_kill path in request_wait_answer() calls fuse_abort_conn() and returns without waiting for FR_FINISHED. If fuse_dev_do_write() is concurrently processing the same request (FR_LOCKED set), the caller frees req->args while it is still being accessed, causing a use-after-free. Fix this by jumping to the existing wait_event(FR_FINISHED) instead of returning early. The wait will not hang because fuse_abort_conn() ensures all requests are ended.