Patch Warnings

A patch warning is a notification that a patch causes or exposes adverse behavior. Patch warnings provide specific information about this incorrect behavior, as well as other important details and recommendations. This information helps you to make decisions about the patch, such as whether to install or remove a patch with a warning from the system.

The Warning Field

You can find patch warning information in the Warning field of a patch's patch details page or patch text file. This field exists only for patches that have a warning. The Warning field is the definitive source of information about a patch warning. The following screen shows the Warning field for patch PHKL_30065.

Warning: 04/01/22 - This Critical Warning has been issued by HP.

- PHKL_30065 introduced behavior that can cause a panic on
systems configured with greater than 32 GB of device swap.
The behavior will occur only if all the following factors occur:

- The system is configured with more device swap than is 
supported by the current value of the swchunk(5) tunable kernel parameter.

- The system has 2 or more swap devices.

- Pages are actually written to the non-primary swap device which 
exceeds the swchunk(5) supported limit.

The Warning field contains the following information:

The issue date of any warnings (year/month/day format)
Whether the patch warning is critical or noncritical (see “Critical and Noncritical Warnings”)
A description of the problem
A suggested course of action for the problem might be provided
A reference to a replacement patch might be provided

See “Finding Information for a Specific Patch” for a description of how you can access a patch details page and a patch text file.

Critical and Noncritical Warnings

Patch warnings are either critical or noncritical. You can find this information in the first line of the Warning field in the patch's patch details page or in the patch text file.

HP considers a patch warning to be critical if the patch causes or exposes a critical problem. Examples of critical patches include the following:

System panic or hang
Process abort, hang, or failure
Data corruption
Severe performance degradation
Application-specific critical issues

HP considers a patch warning to be noncritical if the patch causes or exposes a noncritical problem. Noncritical problems are those other than the ones described previously. Examples of noncritical problems include the following:

Extraneous debug, warning, or error messages
Failure to address all documented issues
Minor regressions in behavior

How to Handle Patch Warnings

Your initial response to a warning for a patch on a system should be to carefully read the associated warning text and research the issue to gain a complete understanding of how or if the warning will impact the system.

Because of the number and complexity of the factors involved, there is no single correct way of dealing with a patch with a warning. The following items show some possible courses of action:

In some cases, such as if you encounter a critical problem on the system, immediate removal of the patch may be necessary.
In many cases, removal and replacement can wait until the next scheduled maintenance window.
In other cases, such as when the problem does not affect the hardware or software configuration, there is no need for you to take any action. In fact, HP discourages unnecessary change because it can cause down time and because there is always some risk when making a change to the system.

Questions to Ask

If you must deal with a patch that has a warning, consider the following questions in deciding whether or not to use, or continue to use, the patch:

Is the system environment susceptible to the problem?
A patch with a warning may not cause problems for every customer. Exposure depends on the system-use models, and whether you have any of the affected configurations. The previous screen is a good example of this situation. Unless the system is configured with greater than 32 GB of device swap and meets all the other conditions listed, the patch warning given for patch PHKL_30065 will have no impact on the system.
Is a replacement patch available, and, if so, is its HP rating acceptable for the system?
A replacement patch may be available. You can use the ITRC Patch Database to attempt to locate such a patch. Simply search using the explicit patch ID of the patch that has a warning. If there is a replacement patch, it will be displayed in the search results page. If a replacement patch exists, you must take into account its advantages and disadvantages. This includes consideration of the patch's HP rating. See “HP-UX Patch Ratings”.

After answering the previous two questions, you must consider the following questions in order to develop an appropriate course of action for your situation:

What is the severity of the problem associated with the patch?
If the patch is already on the system, has it caused any problems?
What is your tolerance for down time if a reboot is necessary?
What is the timing of the next maintenance window?
What are your company's system administration policies?

As a final point, if you choose to remove a patch with a warning from a system, make sure that the patch is not contained in any of the depots used for patch installations. For more information about patch depots, see Chapter 8: “Using Software Depots for Patch Management”.

Advanced Topic: Finding Patches with Warnings

HP provides the HP-UX Software Assistant (SWA) tool at no charge. The SWA tool incorporates key functionality from Security Patch Check, ITRC patch assessment, and more. SWA can perform a number of checks including published security issues, installed patches with warnings, and missing patches with critical fixes. Once an analysis has been performed, you can use SWA to download any recommended patches or patch bundles and create a depot ready for installation. See Chapter 9: “Using HP-UX Software Assistant for Patch Management”.

Patch Warnings

Technical documentation

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The Warning Field

Critical and Noncritical Warnings

How to Handle Patch Warnings

Questions to Ask

Advanced Topic: Finding Patches with Warnings