syzbot

    fragmentation     0
    bp_start          8
  , fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
  device 0 buckets 36-37, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
  device 0 buckets 44-46, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
  device 0 buckets 47-120, fixing
 done
bcachefs (loop0): check_lrus...
bcachefs (loop0): incorrect lru entry: lru fragmentation time 134217728
  u64s 5 type set 18446462598867058688:34:0 len 0 ver 0
  for u64s 13 type alloc_v4 0:34:0 len 0 ver 0: 
    gen 64 oldest_gen 0 data_type free
    journal_seq_nonempty 5
    journal_seq_empty    134217728
    need_discard         0
    need_inc_gen         0
    dirty_sectors        0
    stripe_sectors       0
    cached_sectors       0
    stripe               0
    stripe_redundancy    0
    io_time[READ]        1
    io_time[WRITE]       512
    fragmentation     0
    bp_start          8
  , fixing
 done
bcachefs (loop0): check_backpointers_to_extents...
bcachefs (loop0): backpointer doesn't match btree node it points to:
  u64s 9 type backpointer 0:8126464:0 len 0 ver 0: bucket=0:31:0 btree=xattrs level=1 data_type=btree suboffset=0 len=256 gen=0 pos=SPOS_MAX
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 2285c34bed0abe32 written 16 min_key POS_MIN durability: 1 ptr: 0:31:0 gen 128
  u64s 9 type backpointer 0:8126464:0 len 0 ver 0: bucket=0:31:0 btree=xattrs level=1 data_type=btree suboffset=0 len=256 gen=128 pos=SPOS_MAX, fixing
bcachefs (loop0): backpointer doesn't match extent it points to:
  u64s 9 type backpointer 0:8912896:0 len 0 ver 0: bucket=0:34:0 btree=extents level=0 data_type=user suboffset=0 len=8 gen=0 pos=4099:8:U32_MAX
  u64s 5 type error 4099:8:U32_MAX len 8 ver 0, fixing
bcachefs (loop0): backpointer doesn't match extent it points to:
  u64s 9 type backpointer 0:8921088:0 len 0 ver 0: bucket=0:34:8 btree=extents level=0 data_type=user suboffset=0 len=8 gen=0 pos=536870913:24:U32_MAX
  u64s 5 type error 536870913:24:U32_MAX len 24 ver 0, fixing
 done
bcachefs (loop0): check_extents_to_backpointers...
bcachefs (loop0): scanning for missing backpointers in 5/128 buckets
 done
bcachefs (loop0): check_inodes... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): delete_dead_inodes... done
bcachefs (loop0): done starting filesystem
------------[ cut here ]------------
kernel BUG at fs/bcachefs/fs.c:1323!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5353 Comm: syz.0.0 Not tainted syzkaller #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:bch2_fill_extent+0x96e/0x970 fs/bcachefs/fs.c:1323
Code: 0f 0b e8 55 4b 7f fd 90 0f 0b e8 4d 4b 7f fd e9 f7 fe ff ff e8 43 4b 7f fd 90 0f 0b e8 3b 4b 7f fd 90 0f 0b e8 33 4b 7f fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41
RSP: 0018:ffffc9000d4876a0 EFLAGS: 00010287
RAX: ffffffff8440720d RBX: 0000000000000018 RCX: 0000000000100000
RDX: ffffc9000e0c2000 RSI: 00000000000013b0 RDI: 00000000000013b1
RBP: 0000000000000001 R08: ffff888000382440 R09: 0000000000000004
R10: 0000000000000012 R11: 0000000000000002 R12: 0000000000000000
R13: ffffc9000d487b28 R14: 0000000000000002 R15: 0000000000000002
FS:  00007f9efc76b6c0(0000) GS:ffff88808d007000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa3f0f78000 CR3: 000000003ff02000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 bch2_fiemap+0x2871/0x2a90 fs/bcachefs/fs.c:1538
 ioctl_fiemap fs/ioctl.c:220 [inline]
 do_vfs_ioctl+0x1170/0x1430 fs/ioctl.c:532
 __do_sys_ioctl fs/ioctl.c:596 [inline]
 __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584
 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: 0033:0x7f9efb98ec29
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:00007f9efc76b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9efbbd5fa0 RCX: 00007f9efb98ec29
RDX: 0000200000005dc0 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f9efba11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9efbbd6038 R14: 00007f9efbbd5fa0 R15: 00007ffe9171d808
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_fill_extent+0x96e/0x970 fs/bcachefs/fs.c:1323
Code: 0f 0b e8 55 4b 7f fd 90 0f 0b e8 4d 4b 7f fd e9 f7 fe ff ff e8 43 4b 7f fd 90 0f 0b e8 3b 4b 7f fd 90 0f 0b e8 33 4b 7f fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41
RSP: 0018:ffffc9000d4876a0 EFLAGS: 00010287
RAX: ffffffff8440720d RBX: 0000000000000018 RCX: 0000000000100000
RDX: ffffc9000e0c2000 RSI: 00000000000013b0 RDI: 00000000000013b1
RBP: 0000000000000001 R08: ffff888000382440 R09: 0000000000000004
R10: 0000000000000012 R11: 0000000000000002 R12: 0000000000000000
R13: ffffc9000d487b28 R14: 0000000000000002 R15: 0000000000000002
FS:  00007f9efc76b6c0(0000) GS:ffff88808d007000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa3f0f85000 CR3: 000000003ff02000 CR4: 0000000000352ef0