bcachefs (loop1): bucket 0:26 data type btree ptr gen 0 missing in alloc btree
  while marking u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq ac62141f8dc7e261 written 24 min_key POS_MIN durability: 1 ptr: 0:26:0 gen 0, fixing
Unable to handle kernel paging request at virtual address dfff800000000004
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000004] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 7464 Comm: syz.1.170 Not tainted 6.15.0-rc2-syzkaller-gc72692105976 #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : bch2_snapshot_tree_oldest_subvol+0x188/0x60c fs/bcachefs/snapshot.c:400
lr : __snapshot_t fs/bcachefs/snapshot.h:37 [inline]
lr : snapshot_t fs/bcachefs/snapshot.h:44 [inline]
lr : bch2_snapshot_tree_oldest_subvol+0x4d8/0x60c fs/bcachefs/snapshot.c:400
sp : ffff80009da362f0
x29: ffff80009da36300 x28: dfff800000000000 x27: 0000000000000000
x26: 1ffff00013b46c9e x25: 0000000000000020 x24: 1fffe0001e86012a
x23: 0000000000000038 x22: ffff0000f4300950 x21: 000000000014b780
x20: 0000000000000001 x19: ffff0000f4300000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000805136b8 x15: 0000000000000005
x14: 1fffe00018f56b90 x13: 206e6920746e6574 x12: 7865207463657269
x11: 0000000000080000 x10: 000000000007ffff x9 : ffff8000a354a000
x8 : 0000000000000004 x7 : ffff800082a07af0 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000002
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 bch2_snapshot_tree_oldest_subvol+0x188/0x60c fs/bcachefs/snapshot.c:400 (P)
 bch2_inum_snap_offset_err_msg_trans+0x2c8/0x56c fs/bcachefs/error.c:694
 bch2_indirect_extent_missing_error+0x27c/0x820 fs/bcachefs/reflink.c:192
 gc_trigger_reflink_p_segment fs/bcachefs/reflink.c:392 [inline]
 __trigger_reflink_p+0xdb4/0x1038 fs/bcachefs/reflink.c:432
 bch2_trigger_reflink_p+0x17c/0x244 fs/bcachefs/reflink.c:451
 bch2_key_trigger fs/bcachefs/bkey_methods.h:88 [inline]
 bch2_gc_mark_key+0x43c/0x998 fs/bcachefs/btree_gc.c:639
 bch2_gc_btree fs/bcachefs/btree_gc.c:677 [inline]
 bch2_gc_btrees fs/bcachefs/btree_gc.c:740 [inline]
 bch2_check_allocations+0xf90/0x3a5c fs/bcachefs/btree_gc.c:1042
 bch2_run_recovery_pass+0xf0/0x1d0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x238/0x960 fs/bcachefs/recovery_passes.c:285
 bch2_fs_recovery+0x1aac/0x2d30 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x298/0x588 fs/bcachefs/super.c:1059
 bch2_fs_get_tree+0xa0c/0xef4 fs/bcachefs/fs.c:2253
 vfs_get_tree+0x90/0x28c fs/super.c:1759
 do_new_mount+0x228/0x814 fs/namespace.c:3879
 path_mount+0x5b4/0xde0 fs/namespace.c:4206
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount fs/namespace.c:4407 [inline]
 __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4407
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Code: 9bb76f28 91006108 91008119 d343ff28 (38fc6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9bb76f28 	umaddl	x8, w25, w23, x27
   4:	91006108 	add	x8, x8, #0x18
   8:	91008119 	add	x25, x8, #0x20
   c:	d343ff28 	lsr	x8, x25, #3
* 10:	38fc6908 	ldrsb	w8, [x8, x28] <-- trapping instruction