Backtrace

WARNING: CPU: 1 PID: 421 at fs/btrfs/extent-tree.c:230 btrfs_lookup_extent_info+0x38d/0x3a0
Modules linked in: zram ip_tables i915 crct10dif_pclmul crc32_pclmul crc32c_intel i2c_algo_bit drm_kms_helper ghash_clmulni_intel cec drm serio_raw sdhci_pci e1000e cqhci sdhci firewire_ohci mmc_core firewire_core yenta_socket crc_itu_t wmi video fuse
CPU: 1 PID: 421 Comm: btrfs-cleaner Tainted: G        W         5.11.12-300.fc34.x86_64 #1
Hardware name: Dell Inc. Latitude E6510/02K3Y4, BIOS A06 11/20/2010
RIP: 0010:btrfs_lookup_extent_info+0x38d/0x3a0
Code: a8 0c 00 00 c7 44 24 14 00 00 00 00 48 89 44 24 08 e9 ce fc ff ff 80 48 6a 0c e9 df fc ff ff 48 85 db 0f 85 64 ff ff ff 0f 0b <0f> 0b eb 89 b8 f4 ff ff ff eb ba e9 af a1 6f 00 0f 1f 00 66 66 66
RSP: 0018:ffffb80e40807c70 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000c630000
RDX: 0000000000000000 RSI: 000000000deb8000 RDI: ffff990e0818fb78
RBP: ffff990e094220e0 R08: 0000000000000000 R09: ffff990e094220e0
R10: 000134d5e4399d60 R11: 0000000000000000 R12: ffff990e0818fb78
R13: ffff990e0818fa00 R14: ffff990e0be41478 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff990e13e40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f377c640000 CR3: 0000000104528002 CR4: 00000000000206e0
Call Trace:
 do_walk_down+0x132/0x650
 ? kmem_cache_free+0xf2/0x430
 ? btrfs_lookup_extent_info+0x34f/0x3a0
 walk_down_tree+0xbe/0xe0
 btrfs_drop_snapshot+0x1a4/0x790
 btrfs_clean_one_deleted_snapshot+0xe6/0x100
 cleaner_kthread+0xe5/0x140
 ? btree_invalidatepage+0x40/0x40
 kthread+0x11b/0x140
 ? kthread_associate_blkcg+0xa0/0xa0
 ret_from_fork+0x22/0x30