How To Fix /SMB/Q2P036 - A foreign semaphore is blocking the semaphore release

SAP Error Message - Details

• Message type: E = Error

• Message class: /SMB/Q2P -

• Message number: 036

• Message text: A foreign semaphore is blocking the semaphore release

Self-Explanatory Message

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To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

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Smart SAP Assistant

• What is the cause and solution for SAP error message /SMB/Q2P036 - A foreign semaphore is blocking the semaphore release ?

  The SAP error message /SMB/Q2P036 A foreign semaphore is blocking the semaphore release typically indicates an issue related to inter-process communication (IPC) in the SAP system, particularly with semaphores that are used to manage access to shared resources. This error can occur in various scenarios, often related to the SAP kernel or the underlying operating system.
  Cause:
  
  
  Semaphore Conflicts: The error usually arises when a semaphore that is expected to be released is being held by another process or is in a state that prevents its release. This can happen due to:
  
  A process crashing or not terminating properly, leaving semaphores in an inconsistent state.
  Resource contention where multiple processes are trying to access the same semaphore.
  Misconfiguration in the system settings related to IPC resources.
  
  
  
  Operating System Issues: Sometimes, the underlying operating system may have issues with semaphore management, especially if there are limits on the number of semaphores or if the system is under heavy load.
  
  
  SAP Kernel Bugs: In some cases, this error can be caused by bugs in the SAP kernel or specific patches that may not have been applied.
  
  
  Solution:
  
  
  Check for Zombie Processes: Use system commands (like ps on Unix/Linux) to check for any zombie or orphaned processes that may be holding onto semaphores. Terminate any such processes if necessary.
  
  
  Restart the SAP System: If the issue persists, a restart of the SAP system may be required to clear the semaphore states and release any locks.
  
  
  Review System Logs: Check the SAP system logs (transaction SM21) and operating system logs for any related error messages that could provide more context about the issue.
  
  
  Increase IPC Limits: If the issue is related to resource limits, consider increasing the semaphore limits in the operating system configuration. This may involve adjusting kernel parameters (like sem, shm, etc.) on Unix/Linux systems.
  
  
  Apply SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that address this specific error. There may be patches or updates available that resolve known issues.
  
  
  Consult SAP Support: If the problem continues and you cannot find a resolution, consider reaching out to SAP Support for assistance. They can provide more specific guidance based on your system configuration and version.
  
  
  Related Information:
  
  SAP Kernel Version: Ensure that you are running a supported and stable version of the SAP kernel. Upgrading to the latest version can resolve many underlying issues.
  Operating System Compatibility: Verify that your operating system is compatible with the version of SAP you are running, as incompatibilities can lead to IPC issues.
  Documentation: Review SAP documentation related to IPC and semaphores for best practices and configuration guidelines.
  
  By following these steps, you should be able to diagnose and resolve the semaphore blocking issue in your SAP environment.