bcachefs (loop0): check_btree_backpointers... done
bcachefs (loop0): check_backpointers_to_extents... done
bcachefs (loop0): check_extents_to_backpointers...
bcachefs (loop0): scanning for missing backpointers in 10/128 buckets
 done
bcachefs (loop0): check_alloc_to_lru_refs...
bcachefs (loop0): missing fragmentation lru entry
  u64s 12 type alloc_v4 0:34:0 len 0 ver 0: 
    gen 0 oldest_gen 0 data_type user
    journal_seq_nonempty 5
    journal_seq_empty    134217728
    need_discard         1
    need_inc_gen         1
    dirty_sectors        16
    stripe_sectors       1802251
    cached_sectors       0
    stripe               0
    stripe_redundancy    0
    io_time[READ]        1
    io_time[WRITE]       512
    fragmentation     0
    bp_start          7
  , fixing
 done
bcachefs (loop0): bucket_gens_init... done
bcachefs (loop0): check_snapshot_trees... done
bcachefs (loop0): check_snapshots...
bcachefs (loop0): snapshot points to missing/incorrect tree:
  u64s 8 type snapshot 0:4294967295:0 len 0 ver 0: subvol parent          0 children          0          0 subvol 1 tree 0, fixing
 done
bcachefs (loop0): check_subvols... done
bcachefs (loop0): check_subvol_children... done
bcachefs (loop0): delete_dead_snapshots... done
bcachefs (loop0): check_inodes... done
bcachefs (loop0): check_extents... done
bcachefs (loop0): check_indirect_extents... done
bcachefs (loop0): check_dirents... done
bcachefs (loop0): check_xattrs... done
bcachefs (loop0): check_root... done
bcachefs (loop0): check_unreachable_inodes... done
bcachefs (loop0): check_subvolume_structure... done
bcachefs (loop0): check_directory_structure... done
bcachefs (loop0): check_nlinks... done
bcachefs (loop0): check_rebalance_work... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): delete_dead_inodes... done
bcachefs (loop0): set_fs_needs_rebalance... done
bcachefs (loop0): done starting filesystem
------------[ cut here ]------------
truncate spotted in mem i_size < btree i_size: 10 < 12288
WARNING: CPU: 0 PID: 5325 at fs/bcachefs/fs-io.c:474 bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471
Modules linked in:
CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted 6.16.0-rc3-syzkaller-00121-gf02769e7f272 #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
RIP: 0010:bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471
Code: 00 74 0a 48 8b 7c 24 20 e8 92 40 e9 fd 4c 8b 7c 24 20 49 8b 37 48 8b 94 24 00 01 00 00 48 c7 c7 00 b8 d4 8b e8 46 65 49 fd 90 <0f> 0b 90 90 e9 95 fa ff ff e8 a7 bc 85 fd 4c 8b 7c 24 50 4c 89 ff
RSP: 0018:ffffc9000f677540 EFLAGS: 00010246
RAX: 2f29d599aa580000 RBX: 1ffff1100a811188 RCX: ffff88800035a440
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc9000f6777d0 R08: ffff88801fc24293 R09: 1ffff11003f84852
R10: dffffc0000000000 R11: ffffed1003f84853 R12: ffff888054088c40
R13: ffff888054088d00 R14: 000000000000000a R15: ffff8880540887e8
FS:  00007ff49cb306c0(0000) GS:ffff88808d250000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000043e50000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 notify_change+0xb33/0xe40 fs/attr.c:552
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3517 [inline]
 do_open fs/namei.c:3900 [inline]
 path_openat+0x306c/0x3830 fs/namei.c:4055
 do_filp_open+0x1fa/0x410 fs/namei.c:4082
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff49bd8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007ff49cb30038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff49bfb5fa0 RCX: 00007ff49bd8e929
RDX: 0000000000020200 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007ff49be10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff49bfb5fa0 R15: 00007ffd258a8d48
 </TASK>