[syzbot] [bcachefs?] kernel BUG in bch2_btree_node_iter_init (2)

[syzbot <syzbot+3ba6dd3d414ec2296f3c@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    733923397fd9 Merge tag 'pwm/for-6.16-rc6-fixes' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d4b582580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
dashboard link: https://syzkaller.appspot.com/bug?extid=3ba6dd3d414ec2296f3c
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15fd2a8c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=115bea8c580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-73392339.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/be7feaa77b8c/vmlinux-73392339.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a663b3e31463/bzImage-73392339.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/3e7303eff7fc/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3ba6dd3d414ec2296f3c@syzkaller.appspotmail.com

bcachefs (loop0): 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
------------[ cut here ]------------
kernel BUG at fs/bcachefs/bset.h:287!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5498 Comm: syz.0.16 Not tainted 6.16.0-rc5-syzkaller-00038-g733923397fd9 #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:bkey_cmp_p_or_unp fs/bcachefs/bset.h:287 [inline]
RIP: 0010:bset_search_tree fs/bcachefs/bset.c:1129 [inline]
RIP: 0010:__bch2_bset_search fs/bcachefs/bset.c:1181 [inline]
RIP: 0010:bch2_btree_node_iter_init+0x3961/0x3a50 fs/bcachefs/bset.c:1334
Code: fd 90 0f 0b e8 90 a8 a3 fd 90 0f 0b e8 88 a8 a3 fd 90 0f 0b e8 80 a8 a3 fd 90 0f 0b e8 78 a8 a3 fd 90 0f 0b e8 70 a8 a3 fd 90 <0f> 0b e8 68 a8 a3 fd 90 0f 0b e8 60 a8 a3 fd 90 0f 0b e8 58 a8 a3
RSP: 0018:ffffc90002b5e300 EFLAGS: 00010293
RAX: ffffffff841c7e00 RBX: 000000000000004e RCX: ffff888032b52440
RDX: 0000000000000000 RSI: 000000000000004e RDI: 0000000000000001
RBP: ffffc90002b5e530 R08: ffff888032b52440 R09: 0000000000000002
R10: 000000000000ffff R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88803f849908 R14: ffff888011900288 R15: 0000000000000001
FS:  0000555588091500(0000) GS:ffff88808d21b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faae076b5a3 CR3: 000000001ee4f000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __btree_path_level_init fs/bcachefs/btree_iter.c:617 [inline]
 bch2_btree_path_level_init+0x50b/0xa20 fs/bcachefs/btree_iter.c:637
 btree_path_lock_root fs/bcachefs/btree_iter.c:787 [inline]
 bch2_btree_path_traverse_one+0xfec/0x21d0 fs/bcachefs/btree_iter.c:1203
 bch2_btree_path_traverse fs/bcachefs/btree_iter.h:250 [inline]
 __bch2_btree_iter_peek fs/bcachefs/btree_iter.c:2267 [inline]
 bch2_btree_iter_peek_max+0x9e8/0x58f0 fs/bcachefs/btree_iter.c:2384
 bch2_btree_iter_peek_max_type fs/bcachefs/btree_iter.h:743 [inline]
 bch2_gc_btree fs/bcachefs/btree_gc.c:729 [inline]
 bch2_gc_btrees fs/bcachefs/btree_gc.c:792 [inline]
 bch2_check_allocations+0x120d/0x57b0 fs/bcachefs/btree_gc.c:1094
 bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:484 [inline]
 __bch2_run_recovery_passes+0x392/0x1010 fs/bcachefs/recovery_passes.c:539
 bch2_run_recovery_passes+0x184/0x210 fs/bcachefs/recovery_passes.c:610
 bch2_fs_recovery+0x2690/0x3a50 fs/bcachefs/recovery.c:1005
 bch2_fs_start+0xaaf/0xda0 fs/bcachefs/super.c:1213
 bch2_fs_get_tree+0xb39/0x1520 fs/bcachefs/fs.c:2488
 vfs_get_tree+0x92/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 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: 0033:0x7f6704d900ca
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:00007ffd3cd859c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd3cd85a50 RCX: 00007f6704d900ca
RDX: 00002000000058c0 RSI: 0000200000005900 RDI: 00007ffd3cd85a10
RBP: 00002000000058c0 R08: 00007ffd3cd85a50 R09: 0000000000010000
R10: 0000000000010000 R11: 0000000000000246 R12: 0000200000005900
R13: 00007ffd3cd85a10 R14: 0000000000005923 R15: 0000200000000040
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bkey_cmp_p_or_unp fs/bcachefs/bset.h:287 [inline]
RIP: 0010:bset_search_tree fs/bcachefs/bset.c:1129 [inline]
RIP: 0010:__bch2_bset_search fs/bcachefs/bset.c:1181 [inline]
RIP: 0010:bch2_btree_node_iter_init+0x3961/0x3a50 fs/bcachefs/bset.c:1334
Code: fd 90 0f 0b e8 90 a8 a3 fd 90 0f 0b e8 88 a8 a3 fd 90 0f 0b e8 80 a8 a3 fd 90 0f 0b e8 78 a8 a3 fd 90 0f 0b e8 70 a8 a3 fd 90 <0f> 0b e8 68 a8 a3 fd 90 0f 0b e8 60 a8 a3 fd 90 0f 0b e8 58 a8 a3
RSP: 0018:ffffc90002b5e300 EFLAGS: 00010293
RAX: ffffffff841c7e00 RBX: 000000000000004e RCX: ffff888032b52440
RDX: 0000000000000000 RSI: 000000000000004e RDI: 0000000000000001
RBP: ffffc90002b5e530 R08: ffff888032b52440 R09: 0000000000000002
R10: 000000000000ffff R11: 0000000000000000 R12: dffffc0000000000
R13: ffff88803f849908 R14: ffff888011900288 R15: 0000000000000001
FS:  0000555588091500(0000) GS:ffff88808d21b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faae06c8120 CR3: 000000001ee4f000 CR4: 0000000000352ef0


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