kvm: emulating exchange as write
------------[ cut here ]------------
WARNING: CPU: 1 PID: 10430 at fs/nilfs2/btree.c:2285 nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 10430 Comm: segctord Not tainted 4.14.296-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x20/0x44 kernel/panic.c:547
 report_bug+0x208/0x250 lib/bug.c:183
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:nilfs_btree_assign+0x815/0xcc0 fs/nilfs2/btree.c:2285
RSP: 0018:ffff88804c027a70 EFLAGS: 00010297
RAX: ffff88804de326c0 RBX: 0000000000000001 RCX: 0000000000000008
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff88809bac2890
RBP: ffff88809bac2800 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: ffff88804de326c0 R12: 00000000fffffffe
R13: ffff88804c027cc0 R14: ffff888048037950 R15: 0000000000040103
 nilfs_bmap_assign+0x83/0x170 fs/nilfs2/bmap.c:391
 nilfs_segctor_update_payload_blocknr fs/nilfs2/segment.c:1608 [inline]
 nilfs_segctor_assign fs/nilfs2/segment.c:1642 [inline]
 nilfs_segctor_do_construct+0x1931/0x79c0 fs/nilfs2/segment.c:2069
 nilfs_segctor_construct+0x6db/0x8e0 fs/nilfs2/segment.c:2394
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2502 [inline]
 nilfs_segctor_thread+0x3ad/0xdb0 fs/nilfs2/segment.c:2586
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Kernel Offset: disabled
Rebooting in 86400 seconds..