Backtrace

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0 
Oops: 0000 [#1] SMP NOPTI
CPU: 7 PID: 31347 Comm: kworker/u16:4 Not tainted 5.12.17-300.fc34.x86_64 #1
Hardware name: LENOVO 20T1S0SW00/20T1S0SW00, BIOS N2YET28W (1.17 ) 04/19/2021
Workqueue: netns cleanup_net
RIP: 0010:rb_erase+0x106/0x350
Code: 00 00 48 89 10 48 8b 02 a8 01 0f 84 35 02 00 00 48 83 e0 fc 75 01 c3 48 89 d1 48 89 c2 48 8b 42 08 48 39 c8 75 af 48 8b 42 10 <f6> 00 01 0f 84 1d 01 00 00 48 8b 70 10 48 85 f6 74 05 f6 06 01 74
RSP: 0018:ffffbad8c55d7d90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff91a07f081700 RCX: 0000000000000000
RDX: ffff91a121300bd0 RSI: ffff91a0db8b8150 RDI: ffff91a121300b90
RBP: ffffffffba6ecd60 R08: ffff91a07f081750 R09: 0000000000000000
R10: ffff91a121300bb0 R11: 0000000000000001 R12: ffff91a121300b40
R13: ffff91a0fa7bbd40 R14: ffff91a0420427e0 R15: ffff91a042042794
FS:  0000000000000000(0000) GS:ffff91a72d7c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000058fa10002 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 drop_sysctl_table+0xae/0x150
 unregister_sysctl_table.part.0+0x3b/0x90
 ipv6_frags_exit_net+0x1a/0x40
 ops_exit_list+0x33/0x60
 cleanup_net+0x1ff/0x350
 process_one_work+0x1ec/0x380
 worker_thread+0x53/0x3e0
 ? process_one_work+0x380/0x380
 kthread+0x127/0x150
 ? set_kthread_struct+0x40/0x40
 ret_from_fork+0x1f/0x30
Modules linked in: uinput rfcomm snd_seq_dummy snd_hrtimer xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_nat_tftp nf_conntrack_tftp bridge stp llc ccm 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 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 ip_set cmac nf_tables nfnetlink ip6table_filter ip6_tables iptable_filter snd_soc_skl_hda_dsp snd_soc_hdac_hdmi snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_soc_dmic snd_sof_pci_intel_cnl snd_sof_intel_hda_common soundwire_intel soundwire_generic_allocation soundwire_cadence snd_sof_intel_hda snd_sof_pci snd_sof bnep snd_sof_xtensa_dsp snd_soc_skl snd_soc_hdac_hda snd_hda_ext_core snd_soc_sst_ipc snd_soc_sst_dsp x86_pkg_temp_thermal elan_i2c
 intel_powerclamp coretemp snd_soc_acpi_intel_match snd_soc_acpi sunrpc snd_soc_core kvm_intel snd_compress snd_pcm_dmaengine ac97_bus snd_hda_intel snd_intel_dspcfg iTCO_wdt snd_intel_sdw_acpi intel_pmc_bxt kvm iwlmvm mei_hdcp iTCO_vendor_support mei_wdt snd_hda_codec irqbypass intel_rapl_msr rapl snd_hda_core intel_cstate mac80211 vfat snd_hwdep fat libarc4 intel_uncore snd_seq pcspkr snd_seq_device uvcvideo intel_wmi_thunderbolt wmi_bmof iwlwifi snd_pcm btusb videobuf2_vmalloc i2c_i801 btrtl videobuf2_memops snd_timer i2c_smbus btbcm videobuf2_v4l2 thunderbolt cfg80211 mei_me btintel videobuf2_common bluetooth mei videodev thinkpad_acpi processor_thermal_device processor_thermal_rfim platform_profile ucsi_acpi processor_thermal_mbox ledtrig_audio mc processor_thermal_rapl joydev ecdh_generic snd typec_ucsi intel_rapl_common ecc intel_pch_thermal intel_soc_dts_iosf soundcore int3403_thermal typec rfkill int340x_thermal_zone intel_hid int3400_thermal acpi_pad
 acpi_thermal_rel sparse_keymap zram ip_tables dm_crypt trusted hid_multitouch i915 rtsx_pci_sdmmc mmc_core i2c_algo_bit drm_kms_helper cec crct10dif_pclmul crc32_pclmul crc32c_intel drm nvme e1000e ghash_clmulni_intel nvme_core serio_raw rtsx_pci wmi video pinctrl_cannonlake fuse
CR2: 0000000000000000