panic: invalid allocation length: 0x0

goroutine 662074 [running]:
gvisor.googlesource.com/gvisor/pkg/sentry/platform/filemem.(*FileMem).Allocate(0xc420129b00, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/platform/filemem/filemem.go:232 +0x66f
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*fileReadWriter).WriteFromBlocks(0xc4220fc0d0, 0x7fbe2cbed100, 0xffffffffffffffff, 0x0, 0xff, 0x0, 0x0, 0x0)
	pkg/sentry/fs/tmpfs/inode_file.go:411 +0x2a8
gvisor.googlesource.com/gvisor/pkg/sentry/safemem.(Writer).WriteFromBlocks-fm(0x7fbe2cbed100, 0xffffffffffffffff, 0x0, 0xff, 0x200001ff, 0x7fbe2cbed100, 0xffffffffffffffff)
	pkg/sentry/mm/io.go:309 +0x57
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withInternalMappings(0xc4211c6c80, 0xc731e0, 0xc42000e498, 0x20000100, 0x200001ff, 0x1, 0xc421e7fc20, 0x10d1d18, 0x3b21989d3304a, 0xc421e7fb68)
	pkg/sentry/mm/io.go:464 +0x72c
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withVecInternalMappings(0xc4211c6c80, 0xc731e0, 0xc42000e498, 0x0, 0x1, 0x20000100, 0xff, 0xc400000001, 0xc421e7fc20, 0x153c53c0a38bbf32, ...)
	pkg/sentry/mm/io.go:533 +0x7f1
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).CopyInTo(0xc4211c6c80, 0xc731e0, 0xc42000e498, 0x0, 0x1, 0x20000100, 0xff, 0xc65da0, 0xc4220fc0d0, 0x0, ...)
	pkg/sentry/mm/io.go:309 +0x17c
gvisor.googlesource.com/gvisor/pkg/sentry/usermem.IOSequence.CopyInTo(0xc71a40, 0xc4211c6c80, 0x0, 0x1, 0x20000100, 0xff, 0x0, 0xc731e0, 0xc42000e498, 0xc65da0, ...)
	pkg/sentry/usermem/usermem.go:528 +0xad
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*fileInodeOperations).write(0xc422404480, 0xc731e0, 0xc42000e498, 0xc71a40, 0xc4211c6c80, 0x0, 0x1, 0x20000100, 0xff, 0x0, ...)
	pkg/sentry/fs/tmpfs/inode_file.go:289 +0x198
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*regularFileOperations).Write(0xc42015c2d0, 0xc731e0, 0xc42000e498, 0xc4219eb170, 0xc71a40, 0xc4211c6c80, 0x0, 0x1, 0x20000100, 0xff, ...)
	pkg/sentry/fs/tmpfs/file_regular.go:50 +0x89
gvisor.googlesource.com/gvisor/pkg/sentry/fs.(*File).Pwritev(0xc4219eb170, 0xc731e0, 0xc42000e498, 0xc71a40, 0xc4211c6c80, 0x0, 0x1, 0x20000100, 0xff, 0x0, ...)
	pkg/sentry/fs/file.go:294 +0x1c5
gvisor.googlesource.com/gvisor/pkg/sentry/syscalls/linux.performCallback(0xc420e1d200, 0xc4219eb170, 0x20000200, 0xc4205620c0, 0xc71a40, 0xc4211c6c80, 0x0, 0x1, 0x20000100, 0xff, ...)
	pkg/sentry/syscalls/linux/sys_aio.go:264 +0x2a7
gvisor.googlesource.com/gvisor/pkg/sentry/syscalls/linux.submitCallback.func1()
	pkg/sentry/syscalls/linux/sys_aio.go:342 +0x7c
gvisor.googlesource.com/gvisor/pkg/sentry/fs.Async.func1(0xc421024a80)
	pkg/sentry/fs/fs.go:82 +0x4f
created by gvisor.googlesource.com/gvisor/pkg/sentry/fs.Async
	pkg/sentry/fs/fs.go:80 +0x58