------------[ cut here ]------------
truncate spotted in mem i_size < btree i_size: 130235 < 1048576
WARNING: CPU: 1 PID: 6214 at fs/bcachefs/fs-io.c:474 bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471
Modules linked in:
CPU: 1 UID: 0 PID: 6214 Comm: syz.3.32 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:bchfs_truncate+0xa3b/0xc20 fs/bcachefs/fs-io.c:471
Code: 00 74 0a 48 8b 7c 24 20 e8 92 43 e8 fd 4c 8b 7c 24 20 49 8b 37 48 8b 94 24 00 01 00 00 48 c7 c7 40 b6 54 8b e8 a6 dc 4d fd 90 <0f> 0b 90 90 e9 95 fa ff ff e8 87 0c 89 fd 4c 8b 7c 24 50 4c 89 ff
RSP: 0018:ffffc9000548f4e0 EFLAGS: 00010246
RAX: d2cbac636711f500 RBX: 1ffff1100bcef1ae RCX: 0000000000080000
RDX: ffffc90011467000 RSI: 00000000000016b0 RDI: 00000000000016b1
RBP: ffffc9000548f770 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017124863 R12: ffff88805e778d70
R13: ffff88805e778e20 R14: 000000000001fcbb R15: ffff88805e778890
FS:  00007f39801ec6c0(0000) GS:ffff8881269c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f44558ff000 CR3: 00000000266be000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 notify_change+0xb31/0xe60 fs/attr.c:552
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3508 [inline]
 do_open fs/namei.c:3891 [inline]
 path_openat+0x3078/0x3840 fs/namei.c:4046
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 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/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3981fcebe9
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:00007f39801ec038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f3982206180 RCX: 00007f3981fcebe9
RDX: 0000000000088242 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f3982051e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3982206218 R14: 00007f3982206180 R15: 00007fffd4186c28
 </TASK>