loop0: detected capacity change from 0 to 32768
bcachefs (baafa011-d992-4344-aaf9-4ff0e0bec0ff): Using encoding defined by superblock: utf8-12.1.0
bcachefs (loop0): starting version 1.7: mi_btree_bitmap opts=metadata_checksum=none,data_checksum=none,compression=lz4,metadata_target=/dev/loop0,noinodes_use_key_cache,degraded,journal_flush_disabled,fsck,fix_errors=ask,nojournal_transaction_names
  allowing incompatible features above 0.0: (unknown version)
bcachefs (loop0): recovering from clean shutdown, journal seq 13
bcachefs (loop0): Version upgrade required:
Version upgrade from 0.32: (unknown version) to 1.7: mi_btree_bitmap incomplete
Doing incompatible version upgrade from 0.32: (unknown version) to 1.25: extent_flags
  running recovery passes: check_allocations,check_extents_to_backpointers,check_snapshots,check_subvols,check_inodes,check_dirents,set_fs_needs_rebalance
bcachefs (loop0): running explicit recovery pass check_topology (2), currently at recovery_pass_empty (0)
bcachefs (loop0): bcachefs (loop0): error validating btree node on loop0 at btree inodes level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 2a20405ac3f40602 written 24 min_key 18446744060824649728:0:0 durability: 1 ptr: 0:38:0 gen 0
  node offset 0/24: incorrect min_key: got POS_MIN should be 18446744060824649728:0:0, btree topology error: 
bcachefs (loop0): flagging btree inodes lost data
bcachefs (loop0): running explicit recovery pass check_lrus (14), currently at recovery_pass_empty (0)
bcachefs (loop0): running explicit recovery pass check_backpointers_to_extents (16), currently at recovery_pass_empty (0)
bcachefs (loop0): running explicit recovery pass scan_for_btree_nodes (1), currently at recovery_pass_empty (0)
bcachefs (loop0): error reading btree root btree=inodes level=0: btree_node_read_error, fixing
bcachefs (loop0): bcachefs (loop0): error validating btree node on loop0 at btree dirents level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 267fcf747c875937 written 24 min_key POS_MIN durability: 1 ptr: 0:41:0 gen 0
  node offset 16/24 bset u64s 36: checksum error, type chacha20_poly1305_128: got 2e2929fe1f731311ad6b90403a524670 should be 9c0f2415a667f93682c3af0cd44ed5f4, fix?
bcachefs (loop0): bcachefs (loop0): error validating btree node on loop0 at btree dirents level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 267fcf747c875937 written 24 min_key POS_MIN durability: 1 ptr: 0:41:0 gen 0
  node offset 16/24 bset u64s 36: checksum error, type chacha20_poly1305_128: got 2e2929fe1f731311ad6b90403a524670 should be 9c0f2415a667f93682c3af0cd44ed5f4, fix?
  Unable to continue, halting
bcachefs (loop0): flagging btree dirents lost data
bcachefs (loop0): error reading btree root btree=dirents level=0: btree_node_read_error, fixing
bcachefs (loop0): bcachefs (loop0): error validating btree node on loop0 at btree alloc level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 1818ce08861e3527 written 40 min_key POS_MIN durability: 1 ptr: 0:26:0 gen 0
  node offset 0/40 bset u64s 0: checksum error, type crc32c: got 73622061 should be a1c0cae4, fix?
bcachefs (loop0): bcachefs (loop0): error validating btree node on loop0 at btree alloc level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 1818ce08861e3527 written 40 min_key POS_MIN durability: 1 ptr: 0:26:0 gen 0
  node offset 0/40 bset u64s 0: checksum error, type crc32c: got 73622061 should be a1c0cae4, fix?
  Unable to continue, halting
bcachefs (loop0): flagging btree alloc lost data
bcachefs (loop0): running explicit recovery pass check_alloc_info (13), currently at recovery_pass_empty (0)
bcachefs (loop0): error reading btree root btree=alloc level=0: btree_node_read_error, fixing
==================================================================
BUG: KASAN: use-after-free in poly1305_update include/crypto/poly1305.h:83 [inline]
BUG: KASAN: use-after-free in bch2_checksum+0x209/0x490 fs/bcachefs/checksum.c:157
Read of size 8 at addr ffff888054aa0090 by task syz.0.0/5313

CPU: 0 UID: 0 PID: 5313 Comm: syz.0.0 Not tainted 6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xb4/0x290 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x29a/0x2b0 mm/kasan/generic.c:189
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 poly1305_update include/crypto/poly1305.h:83 [inline]
 bch2_checksum+0x209/0x490 fs/bcachefs/checksum.c:157
 bch2_btree_node_read_done+0x1149/0x5470 fs/bcachefs/btree_io.c:1103
 btree_node_read_work+0x565/0xef0 fs/bcachefs/btree_io.c:1367
 bch2_btree_node_read+0x2151/0x27a0 fs/bcachefs/btree_io.c:-1
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1801 [inline]
 bch2_btree_root_read+0x5e7/0x750 fs/bcachefs/btree_io.c:1823
 read_btree_roots+0x2cb/0x800 fs/bcachefs/recovery.c:582
 bch2_fs_recovery+0x2356/0x37b0 fs/bcachefs/recovery.c:929
 bch2_fs_start+0x70b/0xae0 fs/bcachefs/super.c:1096
 bch2_fs_get_tree+0xad7/0x13b0 fs/bcachefs/fs.c:2507
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1759
 do_new_mount+0x24a/0xa40 fs/namespace.c:3881
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4409
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5b459010a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb5b5407e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb5b5407ef0 RCX: 00007fb5b459010a
RDX: 000020000000f640 RSI: 000020000000f680 RDI: 00007fb5b5407eb0
RBP: 000020000000f640 R08: 00007fb5b5407ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000020000000f680
R13: 00007fb5b5407eb0 R14: 000000000000f636 R15: 0000200000000180
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54aa0
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 ffffea000152a888 ffffea00010fd988 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff888054a9ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888054aa0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888054aa0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888054aa0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888054aa0180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================