Fix nil pointer dereference in metrics value calculator.

The metrics structure passed to volume stat calculator can contain real stats on subset of metrics fields. For example, the metrics structure filled by a CSI driver can have either INODES or BYTES filled, IOW it a valid return. In such cases the volume stat calculator panic with below trace: 0516 21:36:19.013143 14452 runtime.go:69] Observed a panic: "invalid memory address or nil pointer dereference" (runtime error: invalid memory address or nil pointer dereference) /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:76 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:65 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:51 /usr/local/go/src/runtime/panic.go:522 /usr/local/go/src/runtime/panic.go:82 /usr/local/go/src/runtime/signal_unix.go:390 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/api/resource/quantity.go:697 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/api/resource/quantity.go:685 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/kubelet/server/stats/volume_stat_calculator.go:144 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/kubelet/server/stats/volume_stat_calculator.go:125 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/kubelet/server/stats/volume_stat_calculator.go:65 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:152 /home/hchiramm/gopath/src/k8s.io/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:153 /usr/local/go/src/runtime/asm_amd64.s:1337 Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

Fix nil pointer dereference in metrics value calculator.
388a9e1d · Humble Chirammal · 92b2e906 · 388a9e1d
Commit 388a9e1d authored May 23, 2019 by Humble Chirammal
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Showing with 20 additions and 6 deletions

volume_stat_calculator.go pkg/kubelet/server/stats/volume_stat_calculator.go +20 -6

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--- a/pkg/kubelet/server/stats/volume_stat_calculator.go
+++ b/pkg/kubelet/server/stats/volume_stat_calculator.go
@@ -138,12 +138,26 @@ func (s *volumeStatCalculator) calcAndStoreStats() {
 // parsePodVolumeStats converts (internal) volume.Metrics to (external) stats.VolumeStats structures
 func (s *volumeStatCalculator) parsePodVolumeStats(podName string, pvcRef *stats.PVCReference, metric *volume.Metrics, volSpec v1.Volume) stats.VolumeStats {
-	available := uint64(metric.Available.Value())
-	capacity := uint64(metric.Capacity.Value())
+	var available, capacity, used, inodes, inodesFree, inodesUsed uint64
-	used := uint64(metric.Used.Value())
+	if metric.Available != nil {
-	inodes := uint64(metric.Inodes.Value())
+		available = uint64(metric.Available.Value())
-	inodesFree := uint64(metric.InodesFree.Value())
+	}
-	inodesUsed := uint64(metric.InodesUsed.Value())
+	if metric.Capacity != nil {
+		capacity = uint64(metric.Capacity.Value())
+	}
+	if metric.Used != nil {
+		used = uint64(metric.Used.Value())
+	}
+	if metric.Inodes != nil {
+		inodes = uint64(metric.Inodes.Value())
+	}
+	if metric.InodesFree != nil {
+		inodesFree = uint64(metric.InodesFree.Value())
+	}
+	if metric.InodesUsed != nil {
+		inodesUsed = uint64(metric.InodesUsed.Value())
+	}
 	return stats.VolumeStats{
 		Name:   podName,