There is an use-after-free problem for 'eba_tbl' in ubi_create_volume()'s
error handling path:

  ubi_eba_replace_table(vol, eba_tbl)
    vol->eba_tbl = tbl
out_mapping:
  ubi_eba_destroy_table(eba_tbl)   // Free 'eba_tbl'
out_unlock:
  put_device(&vol->dev)
    vol_release
      kfree(tbl->entries)	  // UAF

Fix it by removing redundant 'eba_tbl' releasing.
Fetch a reproducer in [Link].

Fixes: 493cfaea ("mtd: utilize new cdev_device_add helper function")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215965Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>