Hi Grzegorz, On Sat, May 20, 2023 at 02:26:14AM +0200, Grzegorz Uriasz wrote: > > This fixes data corruptions arising from concurrent enabling of a target > devices. When multiple enable calls are made concurrently then it is > possible for the target device to be set up twice which results in a > kernel BUG. > Introduces a per target device mutex for serializing enable requests. Device enable call is already secured by configfs per-file mutex. That is actually per device. So Enable procedures are already not executed simulteniously. Look like you wrongly identified the root cause of double list_add. If you have an evidence that dev->dev_flags could have no DF_CONFIGURED bit, then it meeans that it (dev_flags) is raced in other configuration actions (udev_path, vpd_unit_serial, alias). Bits in dev->dev_flags are written not atomically and if you writes to enable, alias, udev_path,unit_serial files simulteniously, then some bits could be lost. IHMO the best solution is to make dev_flags changes be atomical. BR, Dmitry
