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io_uring_register - register an io_uring instance with the kernel


The io_uring_register() system call is used to register an io_uring instance with the kernel. It sets up various parameters such as io_uring buffers, the io_uring timeout, and the io_uring polled queue depths. It also attaches an io_uring instance to an existing file descriptor.

The call allows for registering files, events, memory ranges and other data in an io_uring instance. The io_uring can then be used for operations such as application controlled buffering and queuing, as well as notifying when data is available.

This system call is convenient when dealing with a range of I/O operations, as it only needs to be called once.


  • fd:unsigned int - a file descriptor for the io_uring instance.
  • opcode:unsigned int - the type of registration to perform with the kernel.
  • arg:void* - pointer to an array of structures that describe the data to register.
  • nr_args:unsigned int - the number of structures in said array.

Available Tags

  • K - Originated from kernel-space.
  • U - Originated from user space (for example, pointer to user space memory used to get it)
  • TOCTOU - Vulnerable to TOCTOU (time of check, time of use)
  • OPT - Optional argument - might not always be available (passed with null value)






Observe behavior of I/O threads undergoing registration

Example Use Case

The io_uring_register system call is useful for monitoring the activity around I/O complex operations such as file access and network communication. It can be used to identify latency issues, detect anomalous behavior, and catch system issues.


The kernel documentation warns that while most of the features of the io_uring_register system call are stable, some internal details (as of 5.3) may still be in flux and may change in future releases.

This document was automatically generated by OpenAI and needs review. It might not be accurate and might contain errors. The authors of Tracee recommend that the user reads the "events.go" source file to understand the events and their arguments better.