------------[ cut here ]------------
truncate spotted in mem i_size < btree i_size: 10 < 57344
WARNING: fs/bcachefs/fs-io.c:474 at bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471, CPU#1: syz.8.1712/14532
Modules linked in:
CPU: 1 UID: 0 PID: 14532 Comm: syz.8.1712 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471
Code: 00 74 0a 48 8b 7c 24 20 e8 a2 c2 e1 fd 4c 8b 7c 24 20 49 8b 37 48 8b 94 24 00 01 00 00 48 c7 c7 80 1f f5 8b e8 c6 cf 40 fd 90 <0f> 0b 90 90 e9 95 fa ff ff e8 67 40 7d fd 4c 8b 7c 24 50 4c 89 ff
RSP: 0018:ffffc90002f47520 EFLAGS: 00010246
RAX: edf76ce936be3400 RBX: 1ffff1100b37e81b RCX: ffff888043ce0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc90002f477a8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1c3a6c8 R12: ffff888059bf40d8
R13: ffff888059bf4198 R14: 000000000000000a R15: ffff888059bf3c90
FS:  00007fe8045566c0(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000bd038 CR3: 0000000052e6e000 CR4: 00000000003526f0
DR0: 0000000000000004 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 notify_change+0xc1a/0xf40 fs/attr.c:546
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3516 [inline]
 do_open fs/namei.c:3899 [inline]
 path_openat+0x306c/0x3830 fs/namei.c:4054
 do_filp_open+0x1fa/0x410 fs/namei.c:4081
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe80378eba9
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:00007fe804556038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe8039d6090 RCX: 00007fe80378eba9
RDX: 000000000000275a RSI: 0000200000000280 RDI: ffffffffffffff9c
RBP: 00007fe803811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe8039d6128 R14: 00007fe8039d6090 R15: 00007fffa582ed88
 </TASK>