BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: free_pcppages_bulk+0x15d/0x510
PGD 0 P4D 0 
Oops: 0002 [#1] PREEMPT SMP NOPTI
Modules linked in: snd_seq_dummy rfcomm bnep nls_iso8859_1 snd_hda_codec_hdmi edac_mce_amd nvidia_uvm(POE) kvm_amd kvm arc4 irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc snd_hda_codec_realtek snd_seq_midi snd_hda_codec_generic snd_seq_midi_event snd_rawmidi aesni_intel aes_x86_64 crypto_simd snd_hda_intel glue_helper cryptd snd_hda_codec snd_hda_core snd_hwdep snd_seq iwlmvm input_leds snd_pcm snd_seq_device mac80211 k10temp snd_timer snd btusb btrtl soundcore btbcm btintel bluetooth iwlwifi ccp joydev ecdh_generic cfg80211 wmi_bmof mxm_wmi shpchp wmi mac_hid sch_fq_codel cuse parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs xor zstd_compress raid6_pq hid_generic hid_corsair usbhid hid nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) drm_kms_helper syscopyarea
 sysfillrect sysimgblt fb_sys_fops igb drm dca i2c_algo_bit ahci ptp ipmi_devintf i2c_piix4 ipmi_msghandler pps_core libahci gpio_amdpt gpio_generic
CPU: 10 PID: 3281 Comm: audacity Tainted: P        W  OE    4.15.0-15-lowlatency #16-Ubuntu
Hardware name: Micro-Star International Co., Ltd MS-7A32/X370 GAMING PRO CARBON AC (MS-7A32), BIOS 2.80 01/26/2018
RIP: 0010:free_pcppages_bulk+0x15d/0x510
RSP: 0018:ffffb37e8a45fa50 EFLAGS: 00010012
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000001
RDX: 0000000000000000 RSI: fffffc590cb5ad80 RDI: ffff94069f356450
RBP: ffffb37e8a45fac8 R08: ffff94069f356380 R09: 0000000000000001
R10: 0000000000000010 R11: fffffc590cb5ada0 R12: 0000000000000000
R13: 0000000000000000 R14: dead000000000100 R15: fffffc590cb5ad80
FS:  00007fba639ddfc0(0000) GS:ffff94069ee80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000361694000 CR4: 00000000003406e0
Call Trace:
 free_unref_page_commit+0xb1/0xf0
 free_unref_page_list+0x108/0x1b0
 release_pages+0x193/0x3e0
 __pagevec_release+0x27/0x40
 truncate_inode_pages_range+0x3bb/0x990
 truncate_inode_pages_final+0x43/0x50
 btrfs_evict_inode+0x85/0x5c0 [btrfs]
 evict+0xc8/0x190
 iput+0x168/0x230
 do_unlinkat+0x19c/0x320
 SyS_unlink+0x1f/0x30
 do_syscall_64+0x73/0x130
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7fba5b22fd47
RSP: 002b:00007fff3abe2ab8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00005619eb6b1740 RCX: 00007fba5b22fd47
RDX: 00005619eb643e70 RSI: 00005619eab33010 RDI: 00005619eb6b1740
RBP: 00007fff3abe2cd0 R08: 0000000000000000 R09: 3732303331746365
R10: 66652f3431343530 R11: 0000000000000202 R12: 0000000000000041
R13: 00005619eb831420 R14: 0000000000000000 R15: 00005619ebb9f280
Code: c1 e3 06 48 8d 14 1e 8b 5a 18 83 fb 80 0f 84 64 03 00 00 48 8d 14 40 49 c1 e2 04 48 8d 14 90 49 8d 14 d2 49 8b 94 10 c0 00 00 00 <4c> 89 5a 08 49 89 57 20 49 89 7f 28 4c 89 1f 48 8d 14 40 48 8d 
RIP: free_pcppages_bulk+0x15d/0x510 RSP: ffffb37e8a45fa50
CR2: 0000000000000008
---[ end trace c380327f31354549 ]---