Explore the powerful io_uring subsystem in Linux and its impact on asynchronous I/O performance in this conference talk by Paul Moore from Microsoft. Delve into the introduction of io_uring in Linux v5.1, its improvements over the existing AIO subsystem, and subsequent developments, including the ability to delegate credentials across process boundaries. Examine the challenges faced in adding Linux Security Module (LSM) controls to io_uring, the reasons behind the delay in implementing these controls, and potential strategies for the LSM community to prevent similar issues in future subsystem developments. Gain insights into the complexities of balancing performance enhancements with security considerations in Linux kernel development.