------------[ cut here ]------------
old_ns_root->mnt_id_unique != 1
WARNING: fs/namespace.c:3112 at create_new_namespace fs/namespace.c:3112 [inline], CPU#1: syz.4.8449/25136
WARNING: fs/namespace.c:3112 at open_new_namespace fs/namespace.c:3172 [inline], CPU#1: syz.4.8449/25136
WARNING: fs/namespace.c:3112 at vfs_open_tree+0xf35/0xfb0 fs/namespace.c:3221, CPU#1: syz.4.8449/25136
Modules linked in:
CPU: 1 UID: 0 PID: 25136 Comm: syz.4.8449 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:create_new_namespace fs/namespace.c:3112 [inline]
RIP: 0010:open_new_namespace fs/namespace.c:3172 [inline]
RIP: 0010:vfs_open_tree+0xf35/0xfb0 fs/namespace.c:3221
Code: 35 78 ff 49 bf 00 00 00 00 00 fc ff df e9 1e fb ff ff e8 5e 35 78 ff 4d 63 ee 4c 8b 64 24 08 e9 64 ff ff ff e8 4c 35 78 ff 90 <0f> 0b 90 e9 d1 f5 ff ff e8 3e 35 78 ff 90 0f 0b 90 e9 18 f6 ff ff
RSP: 0018:ffffc90014a17d80 EFLAGS: 00010283
RAX: ffffffff824d7d44 RBX: 000000008000003d RCX: 0000000000080000
RDX: ffffc9000e117000 RSI: 0000000000000222 RDI: 0000000000000223
RBP: ffffc90014a17eb0 R08: ffffffff8e5fa2eb R09: 1ffffffff1cbf45d
R10: dffffc0000000000 R11: fffffbfff1cbf45e R12: ffff88801eef3dc0
R13: 0000000000001802 R14: ffff888031857d00 R15: dffffc0000000000
FS:  00007fcc2f7c56c0(0000) GS:ffff888125557000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 000000008c694000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __do_sys_open_tree fs/namespace.c:3231 [inline]
 __se_sys_open_tree fs/namespace.c:3229 [inline]
 __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3229
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcc2e99bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcc2f7c5028 EFLAGS: 00000246 ORIG_RAX: 00000000000001ac
RAX: ffffffffffffffda RBX: 00007fcc2ec15fa0 RCX: 00007fcc2e99bf79
RDX: 0000000000001802 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007fcc2ea327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcc2ec16038 R14: 00007fcc2ec15fa0 R15: 00007ffe49c82858
 </TASK>