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

goroutine 1421596 [running]:
panic(0x12296c0, 0x1f83c00)
	GOROOT/src/runtime/panic.go:1065 +0x565 fp=0xc02eded560 sp=0xc02eded498 pc=0x437c65
runtime.panicmem()
	GOROOT/src/runtime/panic.go:212 +0x5b fp=0xc02eded580 sp=0xc02eded560 pc=0x435cbb
runtime.sigpanic()
	GOROOT/src/runtime/signal_unix.go:734 +0x173 fp=0xc02eded5b8 sp=0xc02eded580 pc=0x44fa93
gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs.(*Dentry).releaseKeptDentriesLocked(0xc013a98480, 0x15aa480, 0xc02e596a80)
	pkg/sentry/fsimpl/kernfs/filesystem.go:356 +0x4c fp=0xc02eded698 sp=0xc02eded5b8 pc=0x89dd6c
gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs.(*Filesystem).Release(0xc00535b340, 0x15aa480, 0xc02e596a80)
	pkg/sentry/fsimpl/kernfs/filesystem.go:339 +0xa7 fp=0xc02eded6d0 sp=0xc02eded698 pc=0x89dc67
gvisor.dev/gvisor/pkg/sentry/fsimpl/mqfs.(*filesystem).Release(0xc00535b340, 0x15aa480, 0xc02e596a80)
	pkg/sentry/fsimpl/mqfs/mqfs.go:128 +0x7b fp=0xc02eded6f8 sp=0xc02eded6d0 pc=0x8c6afb
gvisor.dev/gvisor/pkg/sentry/vfs.(*Filesystem).DecRef.func1()
	pkg/sentry/vfs/filesystem.go:88 +0xe4 fp=0xc02eded738 sp=0xc02eded6f8 pc=0x7a1fe4
gvisor.dev/gvisor/pkg/sentry/vfs.(*FilesystemRefs).DecRef(0xc00535b340, 0xc02eded7c0)
	bazel-out/k8-fastbuild-ST-4c64f0b3d5c7/bin/pkg/sentry/vfs/filesystem_refs.go:152 +0x82 fp=0xc02eded7b0 sp=0xc02eded738 pc=0x77e8e2
gvisor.dev/gvisor/pkg/sentry/vfs.(*Filesystem).DecRef(0xc00535b340, 0x15aa480, 0xc02e596a80)
	pkg/sentry/vfs/filesystem.go:83 +0x73 fp=0xc02eded7f0 sp=0xc02eded7b0 pc=0x77de13
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).destroy(0xc005cd72c0, 0x15aa480, 0xc02e596a80)
	pkg/sentry/vfs/mount.go:637 +0x93 fp=0xc02eded840 sp=0xc02eded7f0 pc=0x785893
gvisor.dev/gvisor/pkg/sentry/vfs.(*Mount).DecRef(0xc005cd72c0, 0x15aa480, 0xc02e596a80)
	pkg/sentry/vfs/mount.go:616 +0xaa fp=0xc02eded868 sp=0xc02eded840 pc=0x7857ea
gvisor.dev/gvisor/pkg/sentry/vfs.VirtualDentry.DecRef(0xc005cd72c0, 0xc013a98480, 0x15aa480, 0xc02e596a80)
	pkg/sentry/vfs/vfs.go:1182 +0x7f fp=0xc02eded890 sp=0xc02eded868 pc=0x7944bf
gvisor.dev/gvisor/pkg/sentry/vfs.(*VirtualFilesystem).UmountAt(0xc00023f078, 0x15aa480, 0xc02e596a80, 0xc005cd6a20, 0xc02ededae0, 0xc02ededac4, 0x0, 0x0)
	pkg/sentry/vfs/mount.go:417 +0x5b3 fp=0xc02ededa28 sp=0xc02eded890 pc=0x7848f3
gvisor.dev/gvisor/pkg/sentry/syscalls/linux/vfs2.Umount2(0xc02e596a80, 0x7fac03857580, 0x2, 0x7fac03857589, 0x55805dc2ebd3, 0xffffffff, 0x7fac03857350, 0x0, 0x0, 0x0, ...)
	pkg/sentry/syscalls/linux/vfs2/mount.go:187 +0x35d fp=0xc02ededba8 sp=0xc02ededa28 pc=0xf2de9d
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc02e596a80, 0xa6, 0x7fac03857580, 0x2, 0x7fac03857589, 0x55805dc2ebd3, 0xffffffff, 0x7fac03857350, 0xc000001fa0, 0x13ddd80, ...)
	pkg/sentry/kernel/task_syscall.go:115 +0x1b9 fp=0xc02ededc68 sp=0xc02ededba8 pc=0xa66639
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc02e596a80, 0xa6, 0x7fac03857580, 0x2, 0x7fac03857589, 0x55805dc2ebd3, 0xffffffff, 0x7fac03857350, 0xffffffff, 0x7fac03857350)
	pkg/sentry/kernel/task_syscall.go:290 +0x70 fp=0xc02ededcf0 sp=0xc02ededc68 pc=0xa67910
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc02e596a80, 0xa6, 0x7fac03857580, 0x2, 0x7fac03857589, 0x55805dc2ebd3, 0xffffffff, 0x7fac03857350, 0x0, 0x0)
	pkg/sentry/kernel/task_syscall.go:237 +0xb4 fp=0xc02ededd50 sp=0xc02ededcf0 pc=0xa673f4
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc02e596a80, 0x2, 0xc02e596a80)
	pkg/sentry/kernel/task_syscall.go:204 +0x198 fp=0xc02edede20 sp=0xc02ededd50 pc=0xa66cd8
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0x0, 0xc02e596a80, 0x157e4c0, 0x0)
	pkg/sentry/kernel/task_run.go:327 +0xe15 fp=0xc02ededf60 sp=0xc02edede20 pc=0xa59b95
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc02e596a80, 0x8876)
	pkg/sentry/kernel/task_run.go:100 +0x1e2 fp=0xc02ededfd0 sp=0xc02ededf60 pc=0xa58622
runtime.goexit()
	src/runtime/asm_amd64.s:1371 +0x1 fp=0xc02ededfd8 sp=0xc02ededfd0 pc=0x472861
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start
	pkg/sentry/kernel/task_start.go:380 +0x116