------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:288 at __ns_ref_active_get include/linux/ns_common.h:288 [inline], CPU#0: syz.0.1643/12016
WARNING: ./include/linux/ns_common.h:288 at nsproxy_ns_active_get+0x8c7/0xcb0 fs/nsfs.c:691, CPU#0: syz.0.1643/12016
Modules linked in:
CPU: 0 UID: 0 PID: 12016 Comm: syz.0.1643 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ns_ref_active_get include/linux/ns_common.h:288 [inline]
RIP: 0010:nsproxy_ns_active_get+0x8c7/0xcb0 fs/nsfs.c:691
Code: 0f 0b 90 e9 12 f8 ff ff e8 b6 fa 76 ff 90 0f 0b 90 e9 dc f8 ff ff e8 a8 fa 76 ff 90 0f 0b 90 e9 03 f9 ff ff e8 9a fa 76 ff 90 <0f> 0b 90 e9 cd f9 ff ff e8 8c fa 76 ff 90 0f 0b 90 e9 f4 f9 ff ff
RSP: 0018:ffffc90002fe7d60 EFLAGS: 00010287
RAX: ffffffff824ad596 RBX: ffff888079959af8 RCX: 0000000000080000
RDX: ffffc9000b65b000 RSI: 0000000000001bab RDI: 0000000000001bac
RBP: 00000000f0000701 R08: ffff8880779dea23 R09: 1ffff1100ef3bd44
R10: dffffc0000000000 R11: ffffed100ef3bd45 R12: dffffc0000000000
R13: 1ffff11004d6c47a R14: ffff8880779dea20 R15: ffff8880779de000
FS:  00007fd26f0146c0(0000) GS:ffff888125a79000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd26f013f98 CR3: 00000000798b2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 switch_task_namespaces+0x3e/0x110 kernel/nsproxy.c:240
 ksys_unshare+0x630/0x8c0 kernel/fork.c:3154
 __do_sys_unshare kernel/fork.c:3200 [inline]
 __se_sys_unshare kernel/fork.c:3198 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3198
 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: 0033:0x7fd26e18f6c9
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:00007fd26f014038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fd26e3e5fa0 RCX: 00007fd26e18f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000026020480
RBP: 00007fd26e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd26e3e6038 R14: 00007fd26e3e5fa0 R15: 00007fff5796f578
 </TASK>