Use of atomic.Load64 against unaligned field causes panic on armv7

[brandond]

The atomic operation at

cadvisor/manager/container.go

Line 676 in 99d3532

stats.OOMEvents = atomic.LoadUint64(&cd.oomEvents)

(added by #2829) performs an unaligned load on 32bit systems, or at least armv7l. This results in a panic:

panic: unaligned 64-bit atomic operation

goroutine 13904 [running]:
runtime/internal/atomic.panicUnaligned()
        /usr/local/go/src/runtime/internal/atomic/unaligned.go:8 +0x24
runtime/internal/atomic.Load64(0xfb9a2ec)
        /usr/local/go/src/runtime/internal/atomic/atomic_arm.s:286 +0x14
github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager.(*containerData).updateStats(0xfb9a180)
        /go/src/github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager/container.go:676 +0x438
github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager.(*containerData).housekeepingTick(0xfb9a180, 0x12608b00, 0x5f5e100)
        /go/src/github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager/container.go:587 +0x104
github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager.(*containerData).housekeeping(0xfb9a180)
        /go/src/github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager/container.go:535 +0x3c0
created by github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager.(*containerData).Start
        /go/src/github.com/rancher/k3s/vendor/github.com/google/cadvisor/manager/container.go:122 +0x2c

This same code works fine on arm64 and amd64.

[brandond]

cc @iwankgb @kragniz

[martadinata666]

#3029

[brandond]

Thanks, didn't find that one when searching!