------------[ cut here ]------------
WARNING: kernel/nstree.c:115 at __ns_tree_remove+0x28d/0x330 kernel/nstree.c:115, CPU#1: syz.0.1797/12583
Modules linked in:
CPU: 1 UID: 0 PID: 12583 Comm: syz.0.1797 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__ns_tree_remove+0x28d/0x330 kernel/nstree.c:115
Code: 0f 85 a4 00 00 00 48 8b 04 24 ff 00 48 8b 7c 24 18 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9 79 62 f8 09 e8 94 f1 31 00 90 <0f> 0b 90 e9 cc fd ff ff e8 86 f1 31 00 90 0f 0b 90 e9 ee fd ff ff
RSP: 0018:ffffc90003cdf708 EFLAGS: 00010293
RAX: ffffffff818de3fc RBX: ffff888025ef1020 RCX: ffff888053b8dac0
RDX: 0000000000000000 RSI: ffff888025ef1020 RDI: ffff888025ef1020
RBP: dffffc0000000000 R08: ffffffff8e1eff53 R09: 1ffffffff1c3dfea
R10: dffffc0000000000 R11: fffffbfff1c3dfeb R12: ffff888025ef1020
R13: 1ffff11004bde203 R14: ffff888025ef1000 R15: ffffffff8e1ea7c0
FS:  00007f3d9537b6c0(0000) GS:ffff888125ae1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000054640000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 mnt_ns_tree_remove fs/namespace.c:165 [inline]
 free_mnt_ns+0xd1/0x110 fs/namespace.c:4068
 namespace_unlock+0x529/0x760 fs/namespace.c:1710
 class_namespace_excl_destructor fs/namespace.c:96 [inline]
 copy_mnt_ns+0x6e0/0x870 fs/namespace.c:4174
 create_new_namespaces+0xd1/0x720 kernel/nsproxy.c:78
 copy_namespaces+0x438/0x4b0 kernel/nsproxy.c:175
 copy_process+0x1733/0x3c00 kernel/fork.c:2199
 kernel_clone+0x21e/0x840 kernel/fork.c:2624
 __do_sys_clone kernel/fork.c:2765 [inline]
 __se_sys_clone kernel/fork.c:2749 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2749
 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: 0033:0x7f3d9458eba9
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:00007f3d9537afe8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f3d947d6090 RCX: 00007f3d9458eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000144020080
RBP: 00007f3d94611e19 R08: 0000200000000340 R09: 0000200000000340
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f3d947d6128 R14: 00007f3d947d6090 R15: 00007ffc31b03eb8
 </TASK>