panic: invalid allocation length: 0x0

goroutine 1142870 [running]:
gvisor.googlesource.com/gvisor/pkg/sentry/platform/filemem.(*FileMem).Allocate(0xc42029a000, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0)
	pkg/sentry/platform/filemem/filemem.go:232 +0x66f
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*fileReadWriter).WriteFromBlocks(0xc420b28460, 0x7f6f31a57080, 0xffffffffffffffff, 0x0, 0x11, 0x0, 0x0, 0x0)
	pkg/sentry/fs/tmpfs/inode_file.go:411 +0x2a8
gvisor.googlesource.com/gvisor/pkg/sentry/safemem.(Writer).WriteFromBlocks-fm(0x7f6f31a57080, 0xffffffffffffffff, 0x0, 0x11, 0x20000091, 0x7f6f31a57080, 0xffffffffffffffff)
	pkg/sentry/mm/io.go:309 +0x57
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withInternalMappings(0xc422b38000, 0xc730e0, 0xc420406320, 0x20000080, 0x20000091, 0x1, 0xc4202e4c20, 0x10d1d18, 0x2bee4e3a17c7f, 0xc4202e4b68)
	pkg/sentry/mm/io.go:464 +0x72c
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withVecInternalMappings(0xc422b38000, 0xc730e0, 0xc420406320, 0x0, 0x1, 0x20000080, 0x11, 0xc400000001, 0xc4202e4c20, 0x153bea02cfa189b1, ...)
	pkg/sentry/mm/io.go:533 +0x7f1
gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).CopyInTo(0xc422b38000, 0xc730e0, 0xc420406320, 0x0, 0x1, 0x20000080, 0x11, 0xc65ca0, 0xc420b28460, 0x0, ...)
	pkg/sentry/mm/io.go:309 +0x17c
gvisor.googlesource.com/gvisor/pkg/sentry/usermem.IOSequence.CopyInTo(0xc71940, 0xc422b38000, 0x0, 0x1, 0x20000080, 0x11, 0x0, 0xc730e0, 0xc420406320, 0xc65ca0, ...)
	pkg/sentry/usermem/usermem.go:528 +0xad
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*fileInodeOperations).write(0xc4212f98c0, 0xc730e0, 0xc420406320, 0xc71940, 0xc422b38000, 0x0, 0x1, 0x20000080, 0x11, 0x0, ...)
	pkg/sentry/fs/tmpfs/inode_file.go:289 +0x198
gvisor.googlesource.com/gvisor/pkg/sentry/fs/tmpfs.(*regularFileOperations).Write(0xc420580260, 0xc730e0, 0xc420406320, 0xc4216a54d0, 0xc71940, 0xc422b38000, 0x0, 0x1, 0x20000080, 0x11, ...)
	pkg/sentry/fs/tmpfs/file_regular.go:50 +0x89
gvisor.googlesource.com/gvisor/pkg/sentry/fs.(*File).Pwritev(0xc4216a54d0, 0xc730e0, 0xc420406320, 0xc71940, 0xc422b38000, 0x0, 0x1, 0x20000080, 0x11, 0x0, ...)
	pkg/sentry/fs/file.go:294 +0x1c5
gvisor.googlesource.com/gvisor/pkg/sentry/syscalls/linux.performCallback(0xc42235c900, 0xc4216a54d0, 0x200000c0, 0xc4205dc580, 0xc71940, 0xc422b38000, 0x0, 0x1, 0x20000080, 0x11, ...)
	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(0xc4203428c0)
	pkg/sentry/fs/fs.go:82 +0x4f
created by gvisor.googlesource.com/gvisor/pkg/sentry/fs.Async
	pkg/sentry/fs/fs.go:80 +0x58