Handle kmem.limit_in_bytes removal

kmem.limit_in_bytes has been removed in upstream linux and this patch
is queued to be backported to linux 6.1 stable:

- https://lore.kernel.org/linux-mm/[email protected]/T/
- https://www.spinics.net/lists/stable-commits/msg316619.html

Without this change to libcontainerd, GetStats() will return an error
on the latest kernel(s). A downstream effect is that Kubernetes's
kubelet does not start up. This fix was tested by ensuring that it
unblocks kubelet startup when running on the latest kernel.

Signed-off-by: Jordan Rife <[email protected]>

Author: jrife

libcontainer/cgroups/fs/memory.go

@@ -234,6 +234,12 @@ func getMemoryData(path, name string) (cgroups.MemoryData, error) {
 	memoryData.Failcnt = value
 	value, err = fscommon.GetCgroupParamUint(path, limit)
 	if err != nil {
+		if name == "kmem" && os.IsNotExist(err) {
+			// Ignore ENOENT as kmem.limit_in_bytes has
+			// been removed in newer kernels.
+			return memoryData, nil
+		}
+
 		return cgroups.MemoryData{}, err
 	}
 	memoryData.Limit = value