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 PTI
CPU: 1 PID: 5230 Comm: btrfs Tainted: G           OE     5.12.8-300.fc34.x86_64 #1
Hardware name: System manufacturer System Product Name/PRIME Z370-P, BIOS 0610 01/11/2018
RIP: 0010:strcmp+0xc/0x20
Code: 06 49 89 f8 48 83 c6 01 48 83 c7 01 88 47 ff 84 c0 75 eb 4c 89 c0 c3 0f 1f 80 00 00 00 00 31 c0 eb 08 48 83 c0 01 84 d2 74 0f <0f> b6 14 07 3a 14 06 74 ef 19 c0 83 c8 01 c3 31 c0 c3 66 90 48 85
RSP: 0018:ffffad8508157d80 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8f9cca9e3400 RCX: ffff8f9cca9e3400
RDX: ffff8f9cca9e3400 RSI: ffffffffbc3a3da7 RDI: 0000000000000000
RBP: ffff8f9d2f5c3000 R08: 0001000000000000 R09: 0000000000000000
R10: 0000000000000094 R11: 0000000000000094 R12: 0000000000000000
R13: fffffffffffffffe R14: 0000000000000006 R15: ffff8f9d2f5c3b18
FS:  00007f61dfaab8c0(0000) GS:ffff8fa3e6a40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000022cb1c005 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 btrfs_rm_device+0x3d7/0x500
 ? __check_object_size+0x136/0x150
 ? _copy_from_user+0x3c/0x80
 btrfs_ioctl+0x2053/0x2f80
 ? __handle_mm_fault+0x12f0/0x15c0
 ? selinux_file_ioctl+0x137/0x1e0
 ? __x64_sys_ioctl+0x82/0xb0
 __x64_sys_ioctl+0x82/0xb0
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f61dfba50ab
Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 95 bd 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007fff33a9e2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff33aa04c0 RCX: 00007f61dfba50ab
RDX: 00007fff33a9e320 RSI: 000000005000943a RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
R10: 00007f61dfc22ac0 R11: 0000000000000246 R12: 00007fff33a9e320
R13: 0000000000000001 R14: 00007f61dfaab6a8 R15: 0000000000000000
Modules linked in: uinput snd_seq_dummy snd_hrtimer bridge stp llc 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 nf_tables nfnetlink ip6table_filter ip6_tables iptable_filter vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) sunrpc vfat fat squashfs dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua intel_rapl_msr intel_rapl_common snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi x86_pkg_temp_thermal snd_hda_intel intel_powerclamp coretemp snd_intel_dspcfg snd_intel_sdw_acpi kvm_intel snd_hda_codec snd_hda_core iTCO_wdt snd_hwdep intel_pmc_bxt iTCO_vendor_support ee1004 mei_hdcp kvm snd_seq irqbypass rapl snd_seq_device intel_cstate snd_pcm intel_uncore eeepc_wmi asus_wmi i2c_i801 sparse_keymap pcspkr rfkill wmi_bmof i2c_smbus joydev snd_timer snd mei_me mei soundcore acpi_pad zram ip_tables hid_logitech_hidpp i915 nouveau
 hid_logitech_dj drm_ttm_helper ttm i2c_algo_bit drm_kms_helper mxm_wmi crct10dif_pclmul cec crc32_pclmul crc32c_intel drm ghash_clmulni_intel nvme r8169 nvme_core serio_raw wmi video fuse
CR2: 0000000000000000