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move_mount - reposition an existing mount in the file hierarchy.


The move_mount() system call is designed to allow the repositioning of an existing mount point to a new location within the file system hierarchy.

This system call is a part of the revamped mount API introduced in Linux 5.2 and provides a more flexible and secure way to move mounts, particularly beneficial within user namespaces.

Unlike the traditional mount() system call with the MS_MOVE flag, move_mount() offers a more granular approach to mount operations.


  • from_dfd:int[K] - File descriptor referring to the directory containing the mount point to be moved.
  • from_pathname:const char *[U] - Pathname relative to from_dfd indicating the mount to move.
  • to_dfd:int[K] - File descriptor referring to the directory where the mount point should be moved to.
  • to_pathname:const char *[U] - Pathname relative to to_dfd indicating the target location for the mount.
  • flags:unsigned int[K] - Flags to modify the behavior. As of now, the flag value is typically set to 0.

Available Tags

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




Tracepoint (through sys_enter).


To observe and trace when the move_mount() system call is invoked, capturing details about the source and target mount locations.

Example Use Case

Enhancing containerization tools or sandboxing solutions by reorganizing the mount namespace for better isolation or to achieve specific filesystem layouts without resorting to the older, less granular mount() syscall.


Misuse of the move_mount() system call can lead to unintended changes in the file hierarchy, potentially affecting system stability or introducing security vulnerabilities. Proper validation and checks are essential when utilizing this syscall.

  • open_tree() - Open a reference to a mountpoint for use with the new mount API operations.
  • mount_setattr() - Adjust attributes of a mount.

This document was automatically generated by OpenAI and reviewed by a Human.