Backtrace

WARNING: CPU: 3 PID: 3297 at fs/namespace.c:1187 mntput_no_expire+0x19f/0x250
Modules linked in: uinput snd_seq_dummy snd_hrtimer vboxvideo(OE) drm_ttm_helper xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_nat_tftp nf_conntrack_tftp bridge stp llc nft_objref nf_conntrack_netbios_ns nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_tables ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw iptable_security rfkill ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter qrtr ns vboxsf(OE) sunrpc squashfs loop snd_intel8x0 snd_ac97_codec ac97_bus iTCO_wdt intel_pmc_bxt intel_rapl_msr iTCO_vendor_support snd_seq snd_seq_device intel_rapl_common snd_pcm lpc_ich pcspkr snd_timer snd joydev soundcore i2c_piix4 zram ip_tables vmwgfx ttm drm_kms_helper cec drm crc32c_intel serio_raw e1000 ata_generic video
 vboxguest(OE) pata_acpi ipmi_devintf ipmi_msghandler fuse
CPU: 3 PID: 3297 Comm: close Tainted: G           OE     5.15.6-200.fc35.x86_64 #1
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
RIP: 0010:mntput_no_expire+0x19f/0x250
Code: 0f 84 bc fe ff ff 48 8b 35 c6 45 df 01 b9 01 00 00 00 bf 00 20 00 00 48 c7 c2 c0 7d ff ad e8 48 76 d8 ff e9 9a fe ff ff 79 02 <0f> 0b e8 7a 90 de ff 83 05 03 0b a9 01 01 4c 89 e7 e8 bb bc dc ff
RSP: 0018:ffffac6843af7cc8 EFLAGS: 00010282
RAX: 0000000000000010 RBX: 00000000ffffe5ec RCX: 0000000000000010
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffff9a91c23f6280 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000003 R12: ffffffffade09644
R13: ffffac6843af7e01 R14: 0000000000000000 R15: ffff9a91fa5b8c70
FS:  0000000000000000(0000) GS:ffff9a98c38c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7047dbb000 CR3: 000000014a0bc000 CR4: 00000000000106e0
Call Trace:
 <TASK>
 namespace_unlock+0xf8/0x170
 put_mnt_ns+0x69/0x90
 free_nsproxy+0x17/0x1b0
 do_exit+0x333/0xa90
 ? __slab_free+0xcb/0x390
 do_group_exit+0x33/0xa0
 get_signal+0x16b/0x910
 ? evdev_release+0xd1/0x120
 arch_do_signal_or_restart+0xfd/0x730
 ? kmem_cache_free+0x383/0x3f0
 ? mntput_no_expire+0x37/0x250
 ? call_rcu+0xc8/0x620
 exit_to_user_mode_prepare+0x11a/0x240
 syscall_exit_to_user_mode+0x18/0x40
 do_syscall_64+0x48/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f51f47b701b
Code: Unable to access opcode bytes at RIP 0x7f51f47b6ff1.
RSP: 002b:00007f51f3b919a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000011 RCX: 00007f51f47b701b
RDX: 0000000000000000 RSI: 00007f51f4b3a68f RDI: 0000000000000010
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffe5576a6f
R10: 000000000000068f R11: 0000000000000293 R12: 00007f51f3b92640
R13: 0000000000000001 R14: 00007f51f4742840 R15: 0000000000000000
 </TASK>