panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x48 pc=0x89dd6c]

goroutine 1471469 [running]:
panic(0x12296c0, 0x1f83c00)
	GOROOT/src/runtime/panic.go:1065 +0x565 fp=0xc0227a1560 sp=0xc0227a1498 pc=0x437c65
runtime.panicmem()
	GOROOT/src/runtime/panic.go:212 +0x5b fp=0xc0227a1580 sp=0xc0227a1560 pc=0x435cbb
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:734 +0x173 fp=0xc0227a15b8 sp=0xc0227a1580 pc=0x44fa93
gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs.(*Dentry).releaseKeptDentriesLocked(0xc0284defc0, 0x15aa460, 0xc01af99500)
	pkg/sentry/fsimpl/kernfs/filesystem.go:356 +0x4c fp=0xc0227a1698 sp=0xc0227a15b8 pc=0x89dd6c
gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs.(*Filesystem).Release(0xc01c058dc0, 0x15aa460, 0xc01af99500)
	pkg/sentry/fsimpl/kernfs/filesystem.go:339 +0xa7 fp=0xc0227a16d0 sp=0xc0227a1698 pc=0x89dc67
gvisor.dev/gvisor/pkg/sentry/fsimpl/mqfs.(*filesystem).Release(0xc01c058dc0, 0x15aa460, 0xc01af99500)
	pkg/sentry/fsimpl/mqfs/mqfs.go:128 +0x7b fp=0xc0227a16f8 sp=0xc0227a16d0 pc=0x8c6adb
gvisor.dev/gvisor/pkg/sentry/vfs.(*Filesystem).DecRef.func1()
	pkg/sentry/vfs/filesystem.go:88 +0xe4 fp=0xc0227a1738 sp=0xc0227a16f8 pc=0x7a1fe4
gvisor.dev/gvisor/pkg/sentry/vfs.(*FilesystemRefs).DecRef(0xc01c058dc0, 0xc0227a17c0)
	bazel-out/k8-fastbuild-ST-4c64f0b3d5c7/bin/pkg/sentry/vfs/filesystem_refs.go:152 +0x82 fp=0xc0227a17b0 sp=0xc0227a1738 pc=0x77e8e2
gvisor.dev/gvisor/pkg/sentry/vfs.(*Filesystem).DecRef(0xc01c058dc0, 0x15aa460, 0xc01af99500)
	pkg/sentry/vfs/filesystem.go:83 +0x73 fp=0xc0227a17f0 sp=0xc0227a17b0 pc=0x77de13
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).destroy(0xc003e59800, 0x15aa460, 0xc01af99500)
	pkg/sentry/vfs/mount.go:637 +0x93 fp=0xc0227a1840 sp=0xc0227a17f0 pc=0x785893
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).DecRef(0xc003e59800, 0x15aa460, 0xc01af99500)
	pkg/sentry/vfs/mount.go:616 +0xaa fp=0xc0227a1868 sp=0xc0227a1840 pc=0x7857ea
gvisor.dev/gvisor/pkg/sentry/vfs.VirtualDentry.DecRef(0xc003e59800, 0xc0284defc0, 0x15aa460, 0xc01af99500)
	pkg/sentry/vfs/vfs.go:1182 +0x7f fp=0xc0227a1890 sp=0xc0227a1868 pc=0x7944bf
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).UmountAt(0xc00022f078, 0x15aa460, 0xc01af99500, 0xc00dbf8540, 0xc0227a1ae0, 0xc0227a1ac4, 0x0, 0x0)
	pkg/sentry/vfs/mount.go:417 +0x5b3 fp=0xc0227a1a28 sp=0xc0227a1890 pc=0x7848f3
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Umount2(0xc01af99500, 0x7fa68a369580, 0x2, 0x7fa68a36958b, 0x55a4509fabd3, 0xffffffff, 0x7fa68a369350, 0x0, 0x0, 0x0, ...)
	pkg/sentry/syscalls/linux/vfs2/mount.go:187 +0x35d fp=0xc0227a1ba8 sp=0xc0227a1a28 pc=0xf2de3d
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc01af99500, 0xa6, 0x7fa68a369580, 0x2, 0x7fa68a36958b, 0x55a4509fabd3, 0xffffffff, 0x7fa68a369350, 0xc000001fa0, 0x13ddd80, ...)
	pkg/sentry/kernel/task_syscall.go:115 +0x1b9 fp=0xc0227a1c68 sp=0xc0227a1ba8 pc=0xa66619
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc01af99500, 0xa6, 0x7fa68a369580, 0x2, 0x7fa68a36958b, 0x55a4509fabd3, 0xffffffff, 0x7fa68a369350, 0xffffffff, 0x7fa68a369350)
	pkg/sentry/kernel/task_syscall.go:290 +0x70 fp=0xc0227a1cf0 sp=0xc0227a1c68 pc=0xa678f0
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc01af99500, 0xa6, 0x7fa68a369580, 0x2, 0x7fa68a36958b, 0x55a4509fabd3, 0xffffffff, 0x7fa68a369350, 0x0, 0x0)
	pkg/sentry/kernel/task_syscall.go:237 +0xb4 fp=0xc0227a1d50 sp=0xc0227a1cf0 pc=0xa673d4
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc01af99500, 0x2, 0xc01af99500)
	pkg/sentry/kernel/task_syscall.go:204 +0x198 fp=0xc0227a1e20 sp=0xc0227a1d50 pc=0xa66cb8
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc01af99500, 0x157e4a0, 0x0)
	pkg/sentry/kernel/task_run.go:327 +0xe15 fp=0xc0227a1f60 sp=0xc0227a1e20 pc=0xa59b75
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc01af99500, 0x851a)
	pkg/sentry/kernel/task_run.go:100 +0x1e2 fp=0xc0227a1fd0 sp=0xc0227a1f60 pc=0xa58602
runtime.goexit()
	src/runtime/asm_amd64.s:1371 +0x1 fp=0xc0227a1fd8 sp=0xc0227a1fd0 pc=0x472861
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:380 +0x116