[release-1.12] fix potential panic on numa resources info updating in snapshot

[volcano-sh-bot]

This is an automated cherry-pick of #4892

[gemini-code-assist]

Summary of Changes

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This pull request addresses a critical issue that could lead to a panic during the update of NUMA resource information within the scheduler. The changes ensure that the NUMA scheduler information is always safely initialized and that resource maps are updated without encountering nil pointer dereferences or attempting to access non-existent map entries, thus improving the stability and reliability of the scheduler's resource management.

Highlights

• Panic Prevention: Introduced a nil check for ni.NumaSchedulerInfo to prevent potential panics when the NUMA scheduler information is being initialized or updated, ensuring robust operation.
• Resource Map Safety: Enhanced the logic for updating NUMA resource maps (numaResMap) to safely handle cases where new resources might be introduced. The code now explicitly checks for the existence of a resource before attempting to update it, adding new resources if they are not found, thereby preventing panics.

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[gemini-code-assist]

Code Review

This pull request fixes a potential panic in the NUMA resource information update logic. The changes introduce checks to handle cases where NumaSchedulerInfo is nil and when a resource is not found in the scheduler's resource map, preventing nil pointer dereferences. This makes the snapshotting process more robust.

I've added one comment with a suggestion to further improve the logic by handling the removal of NUMA resources, which would prevent the scheduler from using stale data.

[gemini-code-assist]

This change correctly fixes a potential panic when a resource exists in the new NUMA info but not in the scheduler's cached info. It also handles adding new resources.

However, it doesn't handle the case where a resource is removed from the node. In that scenario, the resource will not be in tmp.NumaResMap, so this loop won't execute for it. The stale resource will remain in ni.NumaSchedulerInfo.NumaResMap, which could lead to the scheduler making incorrect decisions based on outdated information.

To make the logic more robust, I suggest adding another loop to remove any resources from numaResMap that are no longer present in tmp.NumaResMap.

		for resName, resInfo := range tmp.NumaResMap {
			if resourceInfo, ok := numaResMap[resName]; ok {
				klog.V(5).Infof("resource %s Allocatable : current %v new %v on node %s",
					resName, resourceInfo, resInfo, ni.Name)
				if resourceInfo.Allocatable.Size() >= resInfo.Allocatable.Size() {
					resourceInfo.Allocatable = resInfo.Allocatable.Clone()
					resourceInfo.Capacity = resInfo.Capacity
				}
			} else {
				numaResMap[resName] = resInfo
			}
		}
		for resName := range numaResMap {
			if _, ok := tmp.NumaResMap[resName]; !ok {
				delete(numaResMap, resName)
			}
		}