Segfault on 32-bit ARM

[Koston-0xDEADBEEF]

On Linux/armv7l:

# ./neosd convert mslug.zip
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x11fb0]

goroutine 1 [running]:
runtime/internal/atomic.goXadd64(0x256dd0c, 0x400, 0x0, 0x2536400, 0x2536400)
        /usr/lib/go-1.15/src/runtime/internal/atomic/atomic_arm.go:103 +0x1c
github.com/bodgit/plumbing.(*WriteCounter).Write(0x256dd0c, 0x2536400, 0x400, 0x400, 0xc8df76, 0x0, 0x400)
        /root/terraonion/go/pkg/mod/github.com/bodgit/[email protected]/count.go:15 +0x30
github.com/bodgit/plumbing.(*teeReaderAt).ReadAt(0x251e730, 0x2536400, 0x400, 0x400, 0xc8df76, 0x0, 0x22b30, 0x269b4, 0x4)
        /root/terraonion/go/pkg/mod/github.com/bodgit/[email protected]/tee.go:13 +0xa4
archive/zip.readDirectoryEnd(0x31d340, 0x251e730, 0xc8e376, 0x0, 0xb6dac1e8, 0x20, 0xe9)
        /usr/lib/go-1.15/src/archive/zip/reader.go:476 +0x110
archive/zip.(*Reader).init(0x256dd20, 0x31d340, 0x251e730, 0xc8e376, 0x0, 0x282c68, 0x1)
        /usr/lib/go-1.15/src/archive/zip/reader.go:82 +0x34
archive/zip.NewReader(0x31d340, 0x251e730, 0xc8e376, 0x0, 0x0, 0x0, 0x0)
        /usr/lib/go-1.15/src/archive/zip/reader.go:75 +0x84
github.com/bodgit/rom.NewZipReader(0xbe9ede54, 0x9, 0x256dd00, 0x0, 0x0)
        /root/terraonion/go/pkg/mod/github.com/bodgit/[email protected]/reader.go:292 +0x1cc
github.com/bodgit/rom.NewReader(0xbe9ede54, 0x9, 0x259bc0c, 0x2562fa0, 0x261201, 0x7)
        /root/terraonion/go/pkg/mod/github.com/bodgit/[email protected]/reader.go:61 +0x10c
github.com/bodgit/terraonion/neo.(*File).readMameROM(0x25b2000, 0xbe9ede54, 0x9, 0x0, 0x0)
        /root/terraonion/neo/file.go:203 +0x1a8
github.com/bodgit/terraonion/neo.NewFile(0xbe9ede54, 0x9, 0x9, 0x24ba44, 0x438c30)
        /root/terraonion/neo/file.go:105 +0x5c
main.convert(0x256dcc0, 0x7, 0xc)
        /root/terraonion/cmd/neosd/main.go:124 +0x114
github.com/urfave/cli/v2.(*Command).Run(0x25265a0, 0x256da80, 0x0, 0x0)
        /root/terraonion/go/pkg/mod/github.com/urfave/cli/[email protected]/command.go:161 +0x3e8
github.com/urfave/cli/v2.(*App).RunContext(0x252e340, 0x31e780, 0x256f0a0, 0x25140e0, 0x3, 0x4, 0x0, 0x0)
        /root/terraonion/go/pkg/mod/github.com/urfave/cli/[email protected]/app.go:302 +0x608
github.com/urfave/cli/v2.(*App).Run(...)
        /root/terraonion/go/pkg/mod/github.com/urfave/cli/[email protected]/app.go:211
main.main()
        /root/terraonion/cmd/neosd/main.go:225 +0x634

This appears to be caused by a Go bug in 64bit atomic operations on certain 32-bit platforms: golang/go#23345

Quote from sync/atomic bugs section:

On ARM, 386, and 32-bit MIPS, it is the caller's responsibility to arrange for 64-bit alignment of 64-bit words accessed atomically via the primitive atomic functions (types Int64 and Uint64 are automatically aligned). The first word in an allocated struct, array, or slice; in a global variable; or in a local variable (because the subject of all atomic operations will escape to the heap) can be relied upon to be 64-bit aligned.