bcachefs (loop2): mounting version 1.13: (unknown version) opts=metadata_checksum=none,data_checksum=none,noshard_inode_numbers
bcachefs (loop2): recovering from clean shutdown, journal seq 15
bcachefs (loop2): Version downgrade required:
------------[ cut here ]------------
UBSAN: signed-integer-overflow in fs/bcachefs/mean_and_variance.c:127:52
-17293840365824 * -17226286301895 cannot be represented in type 's64' (aka 'long long')
CPU: 0 PID: 3353 Comm: syz.2.17 Not tainted 6.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x67/0xa0 lib/dump_stack.c:106
 ubsan_epilogue+0x5/0x30 lib/ubsan.c:217
 handle_overflow+0x10f/0x120 lib/ubsan.c:248
 mean_and_variance_weighted_update+0x1fe/0x290 fs/bcachefs/mean_and_variance.c:127
 bch2_time_stats_update_one+0x2eb/0x400 fs/bcachefs/util.c:424
 __bch2_time_stats_update+0xb8/0x150 fs/bcachefs/util.c:461
 bch2_time_stats_update fs/bcachefs/util.h:407 [inline]
 bch2_btree_node_mem_alloc+0x48c/0x7c0 fs/bcachefs/btree_cache.c:651
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1721 [inline]
 bch2_btree_root_read+0xda/0x2f0 fs/bcachefs/btree_io.c:1755
 read_btree_roots+0xda/0x1c0 fs/bcachefs/recovery.c:408
 bch2_fs_recovery+0xa45/0x1080 fs/bcachefs/recovery.c:973
 bch2_fs_start+0x120/0x230 fs/bcachefs/super.c:1012
 bch2_fs_open+0xca6/0x13f0 fs/bcachefs/super.c:2062
 bch2_mount+0x239/0x620 fs/bcachefs/fs.c:1831
 legacy_get_tree+0x2d/0x60 fs/fs_context.c:662
 vfs_get_tree+0x26/0xb0 fs/super.c:1784
 do_new_mount+0x132/0x360 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x13c/0x1a0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x92/0x180 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f8504f5830a
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:00007f85041c5e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f85041c5ef0 RCX: 00007f8504f5830a
RDX: 0000200000001000 RSI: 0000200000000000 RDI: 00007f85041c5eb0
RBP: 0000200000001000 R08: 00007f85041c5ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f85041c5eb0 R14: 0000000000004932 R15: 0000200000000040
 </TASK>
---[ end trace ]---