# Security Gateway working in SecureXL User Mode (UPPAK) crashes because of SND core flapping and USIM_x86 segmentation faults

## Symptoms

- When working in SecureXL User Mode (UPPAK), Security Gateway crashes with kernel logs showing segmentation faults in the USIM_x86 process.
- The _$FWDIR/log/dsd.elg_ logs show SND core flapping in dynamic balancing concurrent with the segmentation faults:

```
    update_interfaces_uppak: added 2 SNDs for UPPAK
    update_interfaces_uppak: removed 2 SNDs for UPPAK
    recover_record_runtime_state: Recording runtime state
    FWs filtered average: 60.3 | SNDs filtered average: 0.0
    ```

- The _/var/log/usim_x86.elg_ log shows:

```
    [UPPAK];host_if_msg_ds_update: sent sleep trigger to SND thread on cpu 4, rc = 1
    [SIM4];packet_thread: cpu 5 qid 4 going to sleep ...
    [UPPAK];host_if_msg_ds_update: sent sleep trigger to SND thread on cpu 5, rc = 1
    [SIM4];EAL: Core MIA. Last seen 11999ms ago.
    [UPPAK];Worker on CPU 4 is inactive, excusing it from wd trigger
    [SIM4];EAL: Core died. Last seen 23999ms ago.
    [UPPAK];Threads got STUCK
    ```

## Cause

SND (Secure Network Distributor) core flapping causes segmentation faults in the USIM_x86 process.

## Solution

This problem was fixed. The fix is included in:

- [Jumbo Hotfix Accumulator for R82](https://sc1.checkpoint.com/documents/Jumbo_HFA/R82/Default.htm) starting from Take 60
- [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 120

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).

#### NOTE

This solution has been verified for the specific scenario, described by the combination of Product, Version and Symptoms. It may not work in other scenarios.