losetup-26893 [000] 23442.832217: funcgraph_entry:                  |  loop_control_ioctl() {
      losetup-26893 [000] 23442.832219: funcgraph_entry:                  |    loop_lookup.part.7() {
      losetup-26893 [000] 23442.832220: funcgraph_entry:        0.426 us  |      find_free_cb();
      losetup-26893 [000] 23442.832221: funcgraph_exit:         2.140 us  |    }
      losetup-26893 [000] 23442.832221: funcgraph_exit:         5.796 us  |  }
      losetup-26893 [000] 23442.832366: funcgraph_entry:        0.817 us  |  lo_open();
      losetup-26893 [000] 23442.832374: funcgraph_entry:                  |  lo_ioctl() {
      losetup-26893 [000] 23442.832375: funcgraph_entry:                  |    loop_set_fd() {
      losetup-26893 [000] 23442.832377: funcgraph_entry:        0.230 us  |      loop_validate_file();
      losetup-26893 [000] 23442.832377: funcgraph_entry:  !   269.316 us  |      loop_prepare_queue();
      losetup-26893 [000] 23442.832649: funcgraph_entry:        0.667 us  |      __loop_update_dio();
        loop0-26894 [001] 23442.832714: funcgraph_entry:                  |  loop_kthread_worker_fn() {
      losetup-26893 [001] 23442.834887: funcgraph_exit:   #  2511.581 us  |    }
      losetup-26893 [001] 23442.834888: funcgraph_exit:   #  2513.226 us  |  }
      losetup-26893 [001] 23442.834893: funcgraph_entry:                  |  lo_ioctl() {
      losetup-26893 [001] 23442.834894: funcgraph_entry:                  |    loop_set_status64() {
      losetup-26893 [001] 23442.834894: funcgraph_entry:                  |      loop_set_status() {
systemd-udevd-26895 [000] 23442.836880: funcgraph_entry:                  |  lo_open() {
      losetup-26893 [001] 23442.858173: funcgraph_entry:        3.027 us  |        loop_release_xfer();
      losetup-26893 [001] 23442.858176: funcgraph_entry:        2.220 us  |        loop_config_discard();
      losetup-26893 [001] 23442.858179: funcgraph_entry:        0.786 us  |        __loop_update_dio();
      losetup-26893 [001] 23442.858187: funcgraph_exit:   # 23292.836 us  |      }
      losetup-26893 [001] 23442.858187: funcgraph_exit:   # 23293.764 us  |    }
      losetup-26893 [001] 23442.858188: funcgraph_exit:   # 23294.529 us  |  }
systemd-udevd-26895 [000] 23442.858250: funcgraph_exit:   # 21370.451 us  |  }
      losetup-26893 [001] 23442.858266: funcgraph_entry:        1.190 us  |  lo_release();
systemd-udevd-267   [000] 23442.859186: funcgraph_entry:        1.873 us  |  lo_open();
systemd-udevd-267   [000] 23442.859223: funcgraph_entry:        0.833 us  |  lo_release();