------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#1: ksoftirqd/1/23
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#1: ksoftirqd/1/23
WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#1: ksoftirqd/1/23
Modules linked in:
CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ns_ref_put include/linux/ns_common.h:255 [inline]
RIP: 0010:put_user_ns include/linux/user_namespace.h:189 [inline]
RIP: 0010:put_cred_rcu+0x2c5/0x340 kernel/cred.c:61
Code: 5c 41 5d 41 5e 41 5f 5d e9 48 19 8e 00 e8 83 a5 32 00 4c 89 e7 be 03 00 00 00 e8 56 b4 01 03 e9 b8 fe ff ff e8 6c a5 32 00 90 <0f> 0b 90 eb 9f e8 61 a5 32 00 4c 89 ff be 03 00 00 00 e8 34 b4 01
RSP: 0018:ffffc900001d7888 EFLAGS: 00010246
RAX: ffffffff818ed934 RBX: ffff8880259d39a0 RCX: ffff88801d2fdb80
RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffff888054ee4193 R09: 1ffff1100a9dc832
R10: dffffc0000000000 R11: ffffed100a9dc833 R12: dffffc0000000000
R13: ffff8880259d3900 R14: ffff888054ee4000 R15: ffff888054ee4190
FS:  0000000000000000(0000) GS:ffff888125fc5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3c6269 CR3: 0000000076d8e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861
 handle_softirqs+0x286/0x870 kernel/softirq.c:626
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1067
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>