> Source: [sk182617](https://support.checkpoint.com/results/sk/sk182617)

# sk182617 - Error in pdpd.elg: "T_event_mainloop_iter_select: waiting for sockets to be available failed: Bad file descriptor"

| Property | Value |
|----------|-------|
| Solution ID | sk182617 |
| Date Created | 2024-08-26 |
| Last Modified | 2025-04-29 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R81.20 |
| OS | Gaia |
| Platform | Open Server |

## Symptoms

- * **Symptom:**

  The `pdpd.elg` log file repeatedly records the following error messages:
  * `T_event_mainloop_iter_select: waiting for sockets to be available failed: Bad file descriptor`
  * `SkSelect: [ERROR] select() returned errno = EBADF`
  * `T_event_mainloop_iter_select: waiting for sockets to be available failed: Bad file descriptor`
  * `SkSelect: [ERROR] select() returned errno = EBADF`

  This indicates a persistent issue with socket handling, where the system encounters a "Bad file descriptor" error during the main loop iteration process.
* Identity Awareness does not receive new login events for several hours, affecting many users who fail to connect. The Identity Collector sends login events correctly, but the Security Gateway does not receive them, leading to authentication failures.
* PDPD Core was also generated.

## Cause

In R81.20, Check Point transitioned from a single-threaded `pdpd `daemon using `epoll` to a multithreaded architecture where each thread operates its own main loop with the select system call. This change introduced a limitation of 1024 file descriptors for event monitoring, which can cause issues. A switch back to `epoll` for the threaded loops resolves this problem.

## Solution

This problem was fixed. The fix is included in:  

* [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 89

If you choose not to upgrade, Check Point can supply a Hotfix. [Contact Check Point Support](https://www.checkpoint.com/support-services/.contact-support/) to get a Hotfix for this issue.  
A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.  
For faster resolution and verification, please [collect CPinfo files](http://supportcontent.checkpoint.com/solutions?id=sk92739) from the Security Management Server and Security Gateways involved in the case.  

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://support.checkpoint.com/results/sk/sk168597).

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content