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semctl - a command used to perform operations on System V semaphore sets.


The semctl command is used to perform operations on System V semaphore sets. It has four arguments, a semaphore set identifier, a semaphore number, a command and an optional additional argument. The purpose of this command is to set and retrieve the control information associated with a semaphore set and to set the operational parameters associated with a semaphore. The semctl command can be used to stat, set, mark and get information related to a semaphore set. Some of the drawbacks of using this command is that it can potentially set a semaphore set to a state which can be used in a deadlock situation, or cause race conditions if not handled correctly.


  • semid:int[K] - A semaphore set identifier returned by semget().
  • semnum:int[K] - The number of the semaphore in the set to be affected by cmd.
  • cmd:int[K] - Semaphore control command.
  • arg:unsigned long[K+U+OPT] - Optional structure pointer or value returned from or passed to the kernel.

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)



Type: kprobe + kretprobe. Purpose: To trace the execution of the sys_semctl system call.

Example Use Case

An example use case for this event is a system administrator using the semctl command to monitor the semaphore set for errors or for debugging purposes.


No issues are currently known for this event.

  • semget - get a semaphore set identifier
  • semop - perform semaphore operations

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.